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Old 02-16-2008, 05:35 PM   #1
Dhalgren
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Member Since: Jan 2008
Location: Philly, PA.
Default P-1870 trans code - what to do?

I have a bone stock 1997 C5 with A4. The last couple drives on the highway I got the P-1870 code with all the symptoms like hard shifting, tcc cutout, engine light, etc. Trans temp is about 180 when warm. No idea if the fluid level is correct. Cleared the codes and it's fine around town until I hit the highway again. So now what? It's my daily driver. Can I drive it? Is there any one thing that is causing this? I seem to remember a GM tech bulletin about the valve body. I dread taking it to a trans shop without being armed with enough info to do battle when they tell me it needs a complete rebuild.
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Old 02-16-2008, 06:25 PM   #2
Bill Dearborn
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Here is a list of P1870 related bulletins and the diagnostic from the 97 Service Manual.

Bill

4L60E ( M30 ), 4L65E ( M32 ), Stationary TCC or P1870 Diagnostic Test - kw P0894 DTC clutch converter solenoid transmission valve slip shudder shift automatic #PIP3060 - (Jul 12, 2004)
4L60E (M30) 4L65E (M32) Stationary TCC or P1870 Diagnostic Test.
The following diagnosis might be helpful if the vehicle exhibits the described symptoms in the PI.

Condition/Concern:
This applies to vehicles equipped with 4L60E or 4L65E transmissions. The engine does not stall when performing a "P1870 Diagnostic Test" with the Tech 2 scan tool or when commanding the torque converter clutch enable solenoid on applications that do not have the "P1870 Diagnostic Test" listed.

Recommendation/Instructions:
When diagnosing a DTC P1870 or P0894 Transmission Component Slipping on any vehicle equipped with a 4L60E or 4L65E, be cautious when using the "P1870 Diagnostic Test". There are a wide variety of models over several years that use these transmissions and it seems that the scan tool reacts differently from one application to another. Best practice would be to verify any torque converter clutch slip concern with an actual road test rather then relying on the service bay stall test. This also applies to later models that do not have the "P1870 Diagnostic Test" on the scan tool but rely on commanding the torque converter clutch enable solenoid on in gear and checking for a stall. Technical service bulletin 99-07-30-023 has additional information on diagnostics related to this concern.
.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

4L60E P1870 After Ring and Pinion Replacement #PI00807 - (Feb 12, 2003)4L60E P1870 After Ring and Pinion Replacement.
When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:
The 4L60E automatic transmission may experience a condition of DTC P1870 after the installation of an incorrect ring and pinion gear ratio.
The P1870 DTC will set on a Corvette after installing the incorrect ring and pinion because the Output Speed Sensor (OSS) is calculated off the ring gear in the axle and not the output shaft of the transmission typical of other applications.

Recommendation/Instructions:
Install the correct gear ratio ring and pinion.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.


Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body) #01-07-30-023B - (Mar 22, 2002)
Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)
1996 Buick Roadmaster
1996 Cadillac Fleetwood
1999-2000 Cadillac Escalade
1996-2000 Chevrolet Camaro, Corvette
1996-2000 Pontiac Firebird
1996-2000 Chevrolet and GMC Light Duty Truck Models
1996-2000 Oldsmobile Bravada
with 4L60-E Automatic Transmission (RPO M30)
Built Prior to January 15, 2000 (Julian Date 0015)
This bulletin is being revised to update VIN Breakpoint Date information and revise the Parts Information table. Please discard Corporate Bulletin Number 01-07-30-023A (Section 07 -- Transmission/Transaxle).

Condition
Some customers may comment on a harsh 1-2 upshift and the Check Engine Light or Service Engine Soon indicator is illuminated.
Diagnosis

Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.
The scan tool may show a DTC P1870 set as a history code.
A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93C (200F).

Cause
The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results in poor, or no, TCC apply.
Important
• DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
• When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
• This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).
• When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
• When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL).

Correction
Install a control valve body with the revised TCC regulator and isolator valves. Refer to the Parts Information table below. These valves are used in all transmissions produced after January 15, 2000 (Julian Date 0015), and all of the service parts currently available through GMSPO contain revised TCC regulator and isolator valves.
Important
If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.
• Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).
• The torque converter is not blue or overheated.
• The transmission fluid is not burned or has no burned odor.
• The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments).
Parts Information
Year---Platform--Engine---Trans. (RPO)---Trans. Broadcast Code--P/N
1997---Y Car----5.7L(LS1)--4L60-E(M30)--FFD, YDD--------24217870

Info - Component Slipping/DTC P1870 - Diagnosis #99-07-30-005 - (Mar 18, 1999)
Table 1: TCC System Symptom Table

Table 2: Internal Transmission Symptom Table

Component Slipping/DTC P1870 - Diagnosis
1996 Buick Roadmaster
1996 Cadillac Fleetwood
1999 Cadillac Escalade
1996-99 Chevrolet Camaro, Corvette
1996-99 Pontiac Firebird
1996-99 Chevrolet and GMC C/K, M/L, S/T, G Models
1996-99 Oldsmobile Bravada
1996-99 Holden Commodore
with Hydra-matic 4L60-E (RPO M30)

Description
Many technicians experience difficulty when diagnosing 1996-1999 4L60-E transmissions with a DTC P1870 (Transmission Component Slipping).
The purpose of this bulletin is to provide assistance for technicians that have already completed the DTC P1870 diagnostic table in the Service Manual. This bulletin will provide a diagnostic strategy for solving DTC P1870 concerns as well as give some of the most common causes for a DTC P1870.

General Information
Important
• Chevrolet Camaro, Pontiac Firebird with 3.8L V6 Engine experiencing a slip condition at 70-90 km/h (45-55 mph) when the TCC applies should refer to Corporate Service Bulletin 77-71-70A for calibration re-flash.
• 1996 Chevrolet and GMC C/K, M/L, S/T, G Models, and 1996 Oldsmobile Bravada with VCM and 4L60-E (RPO M30) with a slip or flare on the 1-2 and/or 2-3 upshift, or no 3rd or 4th gear, or launch shudder should refer to Corporate Service Bulletin 66-71-03A to ensure that a poor internal ground in the VCM does not exist.
• A DTC P1870 indicates that a mechanical malfunction exists. If any other DTC's set along with a DTC P1870, then diagnose those first. A DTC P1860 (TCC PWM Solenoid Circuit Electrical) will set if a TCC PWM solenoid circuit failure exists. A DTC P0740 (TCC Enable Solenoid Circuit Electrical) will set if a TCC enable solenoid circuit failure exists.
• When attempting to duplicate DTC P1870, it is critical that a normal operating temperature of 82C (180F) to 93C (200F) be reached. It may be difficult to attain the transmission temperature required to adequately cause the DTC to duplicate. Allow the vehicle to idle to assist in warming the powertrain.
• Optimum speed to duplicate the DTC P1870 is between 89 km/h (55 mph) and 107 km/h (63 mph).
• Commanding the TCC ON and OFF several times with the Tech II is critical to monitoring slip when sticky valves in the valve body are suspect.
• If the customer brought in the vehicle for a temporary harsh 1-2 shift and no driveability concerns are seen during a test drive, then remember that a harsh 1-2 is a result of the PCM commanding maximum line pressure from recognizing a DTC P1870.
• The PCM must recognize that a DTC P1870 has set in two consecutive key cycles to illuminate the MIL. If a DTC P1870 is not recognized on a second key cycle, then normal line pressure returns.
• Vehicles should be inspected for correct tire size, axle ratio, or calibration.

Diagnostic Approach (This is a table with 3 columns; action, yes and no)
Action----Yes-----No
(Attempt to duplicate DTC P1870.
Did you duplicate DTC P1870?)---Go to Slip Check Procedure---Go to TCC System Symptom Table

Slip Check Procedure
This procedure will assist in isolating what area of the transmission is causing your slip, either the TCC system or internal transmission components. After you have isolated the origin of the slip, then utilize the TCC System Symptom Table or the Internal Transmission Symptom Table of this bulletin for most common concerns.
To check for a TCC system concern
TCC slip can occur either hot or cold or in both conditions. First, perform the following test at cold transmission temperatures, then perform the same test at normal operating temperature. Ideal slip from the transmission with the TCC applied is 50 RPM or less under light to normal throttle, no heavy engine load or hard accelerating conditions.
1. Use the Tech II scan tool to monitor TCC slip while driving the vehicle in 4th gear at steady speed with the TCC commanded ON.
2. When the TCC is applied or released (release the TCC with brake pedal, not the scan tool - release the TCC by lightly applying the brake pedal while simultaneously maintaining a steady throttle position), the slip speed should drop or rise 150-300 RPM. If the slip speed does not drop, then the DTC P1870 is being caused by the torque converter system.

(This is a table with 3 columns; action, yes and no)
Action----Yes-----No
Did TCC slip speed drop (150-300)?---Continue Slip Check Procedure for an internal trans concern-----Go to TCC System Symptom Table
To check for an internal transmission concern
Slip should be checked in every gear to isolate in which gear the slip may be occurring. Drive the vehicle in each forward gear range D1, D2, D3 and D4. Command the TCC ON with the Tech II in each gear and monitor slip speed.
Important
Vehicle speed must be over 11 km/h (7 mph). Some TCC slip is normal when the TCC applies directly after 11 km/h (7 mph) is reached.
If the slip speed remains constant from gear to gear, then the condition is most likely TCC related. Example: Slip speed is higher in second and fourth gear than in third gear. This would lead a technician to a possible slipping band.

(This is a table with 3 columns; action, yes and no)
Action----Yes-----No
Is slip speed equal in all gears?-----Go to TCC System Symptom Table------Go to Internal Transmission Symptom Table
Important

These symptom tables are to be used when the following symptoms are associated with a DTC P1870.

TCC System Symptom Table
Symptom
Causes
TCC SLIP (100 RPM SLIP)
• Check for bronze bushing material in the pan and filter. If bronze material is present, then the stator bushings (234) and turbine shaft (241) should be replaced (Bronze bushing may turn black with an acrid odor).
• The turbine shaft and housing (621) should be replaced if damaged.
• In rare instances, it may be necessary to check for an overheated torque converter (24) (Blue and/or distorted converter).
• TCC solenoid (66) - Perform leak check.
• Converter clutch valve (224) in pump should be checked for 13 mm (0.500 in) of bore travel without binding.
• Turbine shaft O-ring seal (618) cut.
• Turbine shaft hole not drilled to full depth. This concern can be checked by squirting trans fluid through the turbine shaft hole to check for full flow. This is a low mileage failure.

NO TCC APPLY (300 RPM SLIP)
• Converter clutch valve (224) stuck closed (Check for debris in valve bore).
• TCC PWM solenoid (396) broken/cracked. Visually inspect solenoid.
• TCC solenoid (66). Perform leak test.
• Turbine shaft O-ring seal (618) omitted.

TCC SLIP WITH STALL STUMBLE
• Converter clutch valve (224) stuck open (TCC is applying).

INTERMITTENT TCC, OK COLD, SLIPS HOT
• TCC PWM solenoid (396). Leak test solenoid.
• The TCC regulator apply valve (380) and/or converter clutch shift valve (224) may be sticking/side-loading. It is possible there will not be any damage to the valve upon inspection. Transmissions produced after 2/1/98 will have a groove cut into the spring end of the regulator apply valve. This design is to help float the valve in its bore (replace valve body assembly).

Internal Transmission Symptom Table
Symptom
Causes
3RD OR 4TH GEAR SLIP
• 3-2 downshift solenoid (394) ball seat retention failed. Leak test solenoid. Usually associated with a 3-4 clutch/band worn.
• 3rd accumulator retainer and ball assembly (40) leaks. Test for proper check ball operation. Usually associated with burned 3-4 clutch.

NO 4TH OR SLIPPING 4TH
• Check ball in the wrong location or extra check ball that has dropped behind the spacer plate during trans assembly. The extra check ball can block the 4th apply servo feed.
• Clutch orifice cup plug (238) not fully pressed in.

SLIP/FLARE IN ANY GEAR
• Pump slide inner spring (207) or outer spring (206) omitted causing a slow slide response.

NO 3RD
• Clutch orifice cup plug (238) blown out.

HARSH 1-2 UPSHIFT
• 4-3 sequence valve (383) stuck in bore by sediment.

NO 2-3 UPSHIFT
• 2-3 shift valve (368) or 2-3 shuttle valve (369) stuck in bore by sediment.

NO 3-4 UPSHIFT
• 3-4 shift valve (385) stuck in bore by sediment.

DTC P1870 Transmission Component Slipping

Range
Gear Shift Solenoid TCC Solenoid TCC PWM Solenoid 2-4 Band Forward Clutch 3-4 Clutch Torque Converter Clutch
1-2 2-3
Overdrive 4th ON OFF ON 90% (ON) Applied Applied Applied Applied

Circuit Description
The Powertrain Control Module (PCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the TCC engaged, the TCC slip speed should be -20 to +30 RPM. The table above indicates solenoid states and transmission components that apply, during 4th gear, with the TCC commanded ON.
When the PCM detects excessive TCC slip when the TCC should be engaged, then DTC P1870 sets. DTC P1870 is a type B DTC.

Conditions for Setting the DTC
DTC P1870 sets if the following conditions are met for three TCC cycles with reported excessive TCC slip conditions, two consecutive times.
• No TP Sensor DTCs P0122 or P0123.
• No VSS Assy. DTCs P0502 or P0503.
• No TCC Sol. Valve DTC P0740.
• No 1-2 SS Valve DTC P0753.
• No 2-3 SS Valve DTC P0758.
• No 3-2 SS Valve Assy. DTC P0785.
• No TCC PWM Sol. Valve DTC P1860.
• The engine speed is greater than 450 RPM for 8 seconds.
• Not in fuel cutoff.
• The vehicle speed is 56-105 km/h (35-65 mph).
• The speed ratio is 0.67-0.9 (the speed ratio is the engine speed divided by the output speed).
• The engine speed is 1200-3500 RPM.
• The engine torque is 40-400 lbs ft.
• The gear range is D4.
• Not in 1st gear
• The TP angle is 10-50%.
• The TFT is between 20-130C (68-266F).
• TCC is commanded On for 5 seconds.
• The TCC is at maximum apply for 5 seconds.
• The shift solenoid performance diagnostic counters are zero.
• The TCC slip speed is 150-800 RPM.
• All conditions met for 7 seconds.

Action Taken When the DTC Sets
• The PCM illuminates the Malfunction Indicator Lamp (MIL).
• The PCM inhibits TCC engagement.
• The PCM commands maximum line pressure.
• The PCM inhibits 4th gear if the transmission is in hot mode.
• The PCM freezes shift adapts from being updated.
• DTC P1870 stores in PCM history.

Conditions for Clearing the MIL/DTC
• The PCM turns OFF the MIL after three consecutive trips without a failure reported.
• A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.
• The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

Diagnostic Aids
• Internal transmission failures could set a DTC P1870.
• A TFP Valve Position Switch malfunction could set a DTC P1870.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

Step 3. This step tests the torque converter for slippage while in a commanded lock-up state.

DTC P1870 Transmission Slipping Component (This is a table with 5 columns for Step #, Action taken, value read, yes and no.)
Step #----Action-------- Value(s)--------- Yes----- No

Step 1
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? -- Go to Step 2
Go to Powertrain OBD System Check

Step 2
Perform the transmission fluid checking procedure.
Refer to Transmission Fluid Checking Procedure .
Was the transmission fluid checking procedure performed? -- Go to Step 3
Go to Transmission Fluid Checking Procedure

Step 3
1. Install the scan tool (tech 1) .
2. Turn ON the ignition, with the engine OFF.
Important
Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.
3. Record the Freeze Frame and Failure Records.
4. Clear the DTCs.
5. With the engine idling and at normal operating temperature, apply the brake pedal.
6. Select each transmission range: D1, D2, D3, D4, N, R and P. Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic.
Does each selected transmission range match the scan tool TFP switch A/B/C display? -- Go to Step 4
Go to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Resistance Check

Step 4
1. Install the Scan Tool .
2. With the engine OFF, turn the ignition switch to the RUN position.
Important
Before clearing the DTC(s), use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.
3.
Record the DTC Freeze Frame and Failure Records, then clear the DTC(s).
4.
Drive the vehicle in 4th gear with the TCC commanded ON.
Is the TCC Slip Speed between the specified values for 7 seconds? 150-800 RPM Go to Step 5
Go to Diagnostic Aids

Step 5
1. Inspect the Torque Converter Clutch Solenoid Valve (TCC Sol. Valve) for the following conditions:
o Internal malfunction (such as sediment or damage)
o Damaged seals
2. Inspect the Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) for the following conditions:
o Internal malfunction (such as sediment or damage)
o Damaged seals
Did you find a condition? -- Go to Step 14
Go to Step 6

Step 6
1. Inspect the 1-2 Shift Solenoid Valve (1-2 SS Valve) for the following conditions:
o Internal malfunction (such as sediment or damage)
o Damaged seals
2. Inspect the 2-3 Shift Solenoid Valve (2-3 SS Valve) for the following conditions:
o Internal malfunction (such as sediment or damage)
o Damaged seals
Did you find a condition? -- Go to Step 14
Go to Step 7

Step 7
Inspect the valve body assembly for a stuck TCC signal valve. Refer to Unit Repair.
Did you find a condition? -- Go to Step 14
Go to Step 8

Step 8
Inspect the torque converter assembly for the following conditions:
• Stator roller clutch not holding
• Internal damage
Did you find a condition? -- Go to Step 14
Go to Step 9

Step 9
Inspect the oil pump assembly for the following conditions:
• Stuck converter clutch valve
• Converter clutch valve assembled backwards
• Mispositioned converter clutch valve retaining ring
• Mispositioned pump to case gasket
• Restricted orifice cup plugs
• Damaged orifice cup plugs
• Over-tightened, or unevenly tightened pump body to cover bolts
Refer to Unit Repair.
Did you find a condition? -- Go to Step 14
Go to Step 10

Step 10
Inspect the input housing and shaft assembly for the following conditions:
• Cut turbine shaft o-ring seal
• Damaged turbine shaft o-ring seal
• Restricted turbine shaft retainer and ball assembly
• Damaged turbine shaft retainer and ball assembly
Refer to Unit Repair.
Did you find a condition? -- Go to Step 14
Go to Step 11

Step 11
Inspect the 2-4 band assembly for the following conditions:
• Worn 2-4 band
• Damaged 2-4 band
• Mispositioned 2-4 band
• Misassembled 2-4 band
• The band anchor pin is not engaged.
• Restricted apply passages in the 2-4 servo assembly
• Blocked apply passages in the 2-4 servo assembly
• Nicks or burrs on the servo pin
• Nicks or burrs on the pin bore in the case
• Damaged fourth servo piston
• Misassembled fourth servo piston
• Damaged band apply pin
• Incorrect band apply pin
• Damaged servo bore in the case
• Missing piston seals
• Cut piston seals
• Damaged piston seals
• Porosity in the pistons
• Porosity in the cover
• Porosity in the case
• Damaged piston seal grooves
• Plugged orifice cup plug
• Missing orifice cup plug
Refer to Unit Repair.
Did you find a condition? -- Go to Step 14
Go to Step 12

Step 12
Inspect the forward clutch assembly for the following conditions:
• Worn clutch plates
• Porosity in the forward clutch piston
• Damaged forward clutch piston
• Missing forward clutch piston inner and outer seals
• Cut forward clutch piston inner and outer seals
• Damaged forward clutch piston inner and outer seals
• Missing input housing to forward clutch housing o-ring seal
• Cut input housing to forward clutch housing o-ring seal
• Damaged input housing to forward clutch housing o-ring seal
• Damaged forward clutch housing
• Damaged forward clutch housing retainer and ball assembly
• Forward clutch housing retainer and ball assembly is not sealing.
Refer to Unit Repair.
Did you find a condition? -- Go to Step 14
Go to Step 13

Step 13
Inspect the 3-4 clutch assembly for the following conditions:
• Worn clutch plates
• Porosity in the 3-4 clutch piston
• Damaged 3-4 clutch piston
• Missing 3-4 clutch inner and outer seals
• Cut 3-4 clutch inner and outer seals
• Damaged 3-4 clutch inner and outer seals
• Damaged 3-4 clutch spring assembly
• Damaged 3-4 clutch apply ring
• Damaged piston seal grooves
• Plugged orifice cup plug
• Missing orifice cup plug
Refer to Unit Repair.
Did you find a condition? -- Go to Step 14
Go to Diagnostic Aids

Step 14
In order to verify your repair, perform the following procedure:
1. Select DTC.
2. Select Clear Info.
3. Operate the vehicle under the following conditions:
o Drive the vehicle in D4, with the TCC ON, and a throttle position of 10-50%.
o Ensure that the TCC Slip Speed is -20 to +30 RPM for at least 7 seconds.
4. Select Specific DTC. Enter DTC P1870.
Has the test run and passed? -- System OK Begin the diagnosis again. Go to Step 1
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Old 02-16-2008, 07:55 PM   #3
angel71rs
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Quote:
Originally Posted by Dhalgren View Post
Can I drive it? Is there any one thing that is causing this? I seem to remember a GM tech bulletin about the valve body.
You risk burning up the clutch in the converter if you keep driving it. Root cause is usually the TCC valve wearing out the bore it slides in. You could have valve body replaced, alternatives discussed here:

http://www.ls1tech.com/forums/showthread.php?t=815771
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Old 02-17-2008, 12:22 AM   #4
coldwater-echelon
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Been there done that, I had the same problem. Get the valve body repaired/replaced and the problem will go away. I wanna say it cost me around $325.
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Old 02-17-2008, 01:58 AM   #5
tblu92
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The hard shifting and strange TCC operation is Not the cause of the P1870 but rather a by-product of the code (trans components slipping)
When you get a P1870 the trans goes into a sort of "limp " mode " to get you home--It sets the line pressure at MAXIMUM in hopes you will have enough pressure to drive a few miles--With full line presure the shifts especially at slow speeds bang violently and the TCC will kick in & out with a mind of its own--Being the car in totally stock you probably have the valve body going down as mentioned---This code is very common with stall converters--although with a stall converter it is usually a false code or a tuning issue---
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Old 02-17-2008, 11:02 AM   #6
Dhalgren
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Thanks all for the great info so far. Been doing some poking around with the info provided. I'm thinking of going with the Transgo kit for starters.
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Old 02-17-2008, 11:31 AM   #7
Chevy Guy
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These codes almost always result in a tear down. I just had this on my Grand Prix (although at 126k miles) and what it turns out to be more often than not is an issue with the valve body or TC electronics in the trans. If the TC was bad, there would be other more obvious indicators.
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Old 02-17-2008, 01:34 PM   #8
angel71rs
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Quote:
Originally Posted by Dhalgren View Post
I'm thinking of going with the Transgo kit for starters.
As long as you're going in there, recommend you replace crappy factory seperator plate with the beefier TransGo plate, it's ~ 20 bucks, local trans supply shop had it in stock. Review of my TransGo install has plate PN:

http://www.ls1tech.com/forums/showthread.php?t=658369
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Old 02-29-2008, 03:05 PM   #9
Dhalgren
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O.K. update, have a good trans shop that put in the new separator plate I gave them and instead of the Transgo kit used the reamer kit process. Still getting the code as current so they are saying rebuild time. He was surprised that didn't work as it usually fixes 98% of them, lucky me. One thing he did mention was a GM bulletin on flashing the PCM first. I asked the stealership about that and just got blank stares back. I did see a mention of that above but there is little info on if that applies to a '97 'vette and if it's worthwhile. Hate to have them do a rebuild and still have the issue because of the PCM.
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Old 04-16-2009, 09:23 AM   #10
JRS_C5
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I know this thread is old, but I have the same code P1870 and the car will not shift to 4th gear at WOT. It simply remains in third and hits the rev limiter at about 90mph. 1-2 shifts fine, 2-3 is also fine, 3-4 is fine at normal throttle (less than 1/2). When driving in 4th it seems like it comes in and out of lock up sometimes.(the engine tone changes but the rpms not so much) While driving over 45mph with lockup on, I touch the brakes and I can feel lockup turn off then back on. The trans. temperature averages from 180-205 when hot.

Could this be a bad 3-4 clutch band or should I just put in a new valve body first and see what happens?

The service manual shows this---- NO 4TH OR SLIPPING 4TH
Check ball in the wrong location or extra check ball that has dropped behind the spacer plate during trans assembly. The extra check ball can block the 4th apply servo feed.
Clutch orifice cup plug (238) not fully pressed in.
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Old 04-18-2009, 11:37 PM   #11
trae1997
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i have the same problem on my 97 what was the total for getting the problem fixed
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Old 04-18-2009, 11:43 PM   #12
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i had that same code in my 97 but i had the erased and it has not come back on yet and at wot all gears shift fine but i am kinda worried if it is the valve body any thoughts
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Old 04-19-2009, 12:48 PM   #13
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I haven't had mine fixed yet, but I just ordered a rebuilt valve body for $100 from ebay. The guy give like a 30 day money back or exchange warranty. As soon as that gets here I will put it on and see if it fixes my problem. If it does fix my problem then a lil later on I can buy a whole new one from GM. I didnt want to spend 350 for a new one without knowing exactly if that was the problem. I'll post the results on here as soon as I get it on.
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Old 04-19-2009, 01:24 PM   #14
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Is your cel light still on if not is your trans still having a problem at wot. I had my code erased and it has not come back on and even at wot all gear are shifting fine so i am confused as to what happen.are you driving your vette or have you parked it until you get it fixed
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Old 04-20-2009, 08:42 AM   #15
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No my CEL is no longer on. I erased the code but it still won't whift at WOT. I'm still driving it like that, I just keep an eye on my trans fluid temperature. The CEL doesn't come back on unless I drive like at 45-55 at a constant steady speed, at that point the transmission starts going in and out of lock-up, causing it to detect slip and cause the P1870 code. Maybe that's why your code hasn't come back on, you have to meet certain requirements for the code to come on. Whatever is causing your code has to occur at least once in two consecutive driving cycles for the CEL to come on.



*DTC P1870 sets if the following conditions are met for three TCC cycles with reported excessive TCC slip conditions, two consecutive times.

-No TP Sensor DTCs P0122 or P0123.
-No VSS Assy. DTCs P0502 or P0503.
-No TCC Sol. Valve DTC P0740.
-No 1-2 SS Valve DTC P0753.
-No 2-3 SS Valve DTC P0758.
-No 3-2 SS Valve Assy. DTC P0785.
-No TCC PWM Sol. Valve DTC P1860.
-The engine speed is greater than 450 RPM for 5 seconds.
-Not in fuel cutoff.
-The vehicle speed is 56-105 km/h (35-65 mph).
-The speed ratio is 0.67-0.90 (the speed ratio is the engine speed divided by the output speed).
-The engine speed is 1200-3500 RPM.
-The engine torque is 40-400 lbs ft.
-The gear range is D4.
-Not in 1st gear.
-The TP angle is 10-50%.
-The TFT is between 20-130C (68-266F).
-TCC is commanded On for 5 seconds.
-The TCC is at maximum apply for 1 second.
-The shift solenoid performance diagnostic counters are zero.
-The TCC slip speed is 80-800 RPM.
-All conditions met for 7 seconds.

*Important
The following actions may occur before the DTC sets.


*If the TCC is commanded ON and at maximum apply for 5 seconds, the TP angle is 10-40%, and the transmission slip counter has incremented to either 1 or 2 (out of 3 to increment the fail counter for the current ignition cycle), then the following slip conditions and actions may increment the fail counter for the current ignition cycle: *These conditions must occur sequentially.
-Condition A: If the TCC slip speed is 80-800 RPM for 7 seconds, then the PCM will command maximum line pressure and freeze shift adapts from being updated.
-Condition B: If Condition A is met and the TCC slip speed is 80-800 RPM for 7 seconds, then the PCM will command the TCC OFF for 1.5 seconds.
-Condition C: If Condition B is met and the TCC slip speed is 80-800 RPM for 7 seconds, then the fail counter on the current ignition cycle is incremented. Two consecutive fail counts are required to set DTC P1870 (type B).
*The above slip conditions and actions may be disregarded if the TCC is commanded OFF at any time as a result of a driving maneuver (sudden acceleration or deceleration).

Last edited by JRS_C5; 04-20-2009 at 08:45 AM.
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Old 01-31-2010, 03:30 PM   #16
Unleashed
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sorry to bring this back to life , but im just searching as any member should do on this forum

where should the transmission fluid be in tempreture whats the idealistic number ?
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Old 02-04-2010, 04:29 PM   #17
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anyone ?
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Old 02-05-2010, 12:34 PM   #18
Mike Mercury
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Quote:
Originally Posted by Unleashed View Post
sorry to bring this back to life , but im just searching as any member should do on this forum

where should the transmission fluid be in tempreture whats the idealistic number ?

the warning alarm doesn't go-off until 260 degrees. Mine runs about 180-190 during normal street driving.
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Old 02-05-2010, 12:34 PM
 
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