P1860 & 1870?
Thread Starter
Melting Slicks
Joined: Oct 2002
Posts: 2,151
Likes: 1
From: N.CHARLESTON SC
P1860 & 1870?
My car is a 98 with 70k miles. Its an auto with a Vortec,stock gears and tranny. Couple of times the car would not shift from 1st to 2nd. Finally took it to the shop and after pulling all the codes....these were two.
He was telling me that my tranny was on it's last leg. Need new transmission,torque converter and would also need a new differential with higher gears(3:42's)
. I have searched and have read where some have done the TCC rebuild kit to avoid spending 7 grand(as quoted)!! What can I do other than roll this car off a cliff!! Love this car but....DAYUM
He was telling me that my tranny was on it's last leg. Need new transmission,torque converter and would also need a new differential with higher gears(3:42's)
. I have searched and have read where some have done the TCC rebuild kit to avoid spending 7 grand(as quoted)!! What can I do other than roll this car off a cliff!! Love this car but....DAYUM
Racer
Joined: Jul 2010
Posts: 262
Likes: 2
From: Shawnee Kansas
P1860
Circuit Description
The Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) controls the fluid acting on the converter clutch valve. The converter clutch valve controls the TCC application and release. The solenoid attaches to the control valve body within the transmission. The solenoid receives ignition voltage through circuit 339. The Powertrain Control Module (PCM) controls the solenoid by providing a ground path on circuit 418. Current flows through the solenoid coil according to the duty cycle (percentage of ON and OFF time). The TCC PWM Sol. Valve provides a smooth engagement of the torque converter clutch by operating during a duty cycle percent of ON time. When the PCM detects a continuous open or short to ground in the TCC PWM Sol. Valve circuit or the TCC PWM Sol. Valve, then DTC P1860 sets. DTC P1860 is a type A DTC.
Conditions for Setting the DTC
The system voltage is 8-16 volts.
The engine speed is greater than 450 RPM for 5 seconds.
Not in fuel cutoff.
The PCM commands first gear.
The TCC duty cycle is less than 10% or greater than 90%.
All of the above conditions are met for 5 seconds and either of the following fail conditions occurs for 5 seconds:
The PCM commands the solenoid ON (90%) and the voltage input remains high (B+).
The PCM commands the solenoid OFF (0%) and the voltage input remains low (0.0 volt).
Action Taken When the DTC Sets
The PCM illuminates the Malfunction Indicator Lamp (MIL).
The PCM inhibits TCC engagement.
The PCM inhibits 4th gear if the transmission is in hot mode.
The PCM freezes shift adapts from being updated.
DTC P1860 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
Inspect the wiring at the PCM, the transmission connector and all other circuit connecting points for the following conditions:
A bent terminal
A backed out terminal
A damaged terminal
Poor terminal tension
A chafed wire
A broken wire inside the insulation
Moisture intrusion
Corrosion
When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
This step tests for voltage to the solenoid.
This step tests the ability of the PCM and wiring to control the ground circuit.
This step tests the resistance of the TCC PWM Sol. Valve and the Automatic Transmission Wiring Harness Assembly.
P1870
Circuit Description
The Powertrain Control Module (PCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the Torque Converter Clutch (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 +40 RPM. The table above indicates shift 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 Throttle Position Sensor (TPS) DTCs P0122 or P0123.
No Vehicle Speed Sensor (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 Torque Converter Clutch Pulse Width Modulation Solenoid Valve (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 Transmission Fluid Temperature (TFT) is between 20-130°C (68-266°F).
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 tail 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).
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 DTC P1870.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
This step tests the torque converter for slippage while in a commanded lock-up state.
© 2011 ALLDATA LLC. All rights reserved.
Terms of Use
Circuit Description
The Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) controls the fluid acting on the converter clutch valve. The converter clutch valve controls the TCC application and release. The solenoid attaches to the control valve body within the transmission. The solenoid receives ignition voltage through circuit 339. The Powertrain Control Module (PCM) controls the solenoid by providing a ground path on circuit 418. Current flows through the solenoid coil according to the duty cycle (percentage of ON and OFF time). The TCC PWM Sol. Valve provides a smooth engagement of the torque converter clutch by operating during a duty cycle percent of ON time. When the PCM detects a continuous open or short to ground in the TCC PWM Sol. Valve circuit or the TCC PWM Sol. Valve, then DTC P1860 sets. DTC P1860 is a type A DTC.
Conditions for Setting the DTC
The system voltage is 8-16 volts.
The engine speed is greater than 450 RPM for 5 seconds.
Not in fuel cutoff.
The PCM commands first gear.
The TCC duty cycle is less than 10% or greater than 90%.
All of the above conditions are met for 5 seconds and either of the following fail conditions occurs for 5 seconds:
The PCM commands the solenoid ON (90%) and the voltage input remains high (B+).
The PCM commands the solenoid OFF (0%) and the voltage input remains low (0.0 volt).
Action Taken When the DTC Sets
The PCM illuminates the Malfunction Indicator Lamp (MIL).
The PCM inhibits TCC engagement.
The PCM inhibits 4th gear if the transmission is in hot mode.
The PCM freezes shift adapts from being updated.
DTC P1860 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
Inspect the wiring at the PCM, the transmission connector and all other circuit connecting points for the following conditions:
A bent terminal
A backed out terminal
A damaged terminal
Poor terminal tension
A chafed wire
A broken wire inside the insulation
Moisture intrusion
Corrosion
When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
This step tests for voltage to the solenoid.
This step tests the ability of the PCM and wiring to control the ground circuit.
This step tests the resistance of the TCC PWM Sol. Valve and the Automatic Transmission Wiring Harness Assembly.
P1870
Circuit Description
The Powertrain Control Module (PCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the Torque Converter Clutch (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 +40 RPM. The table above indicates shift 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 Throttle Position Sensor (TPS) DTCs P0122 or P0123.
No Vehicle Speed Sensor (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 Torque Converter Clutch Pulse Width Modulation Solenoid Valve (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 Transmission Fluid Temperature (TFT) is between 20-130°C (68-266°F).
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 tail 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).
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 DTC P1870.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
This step tests the torque converter for slippage while in a commanded lock-up state.
© 2011 ALLDATA LLC. All rights reserved.
Terms of Use
Racer
Joined: Jul 2010
Posts: 262
Likes: 2
From: Shawnee Kansas
It is possible that you may have a valve body and Solenoid / Elec. Problem.
I would have the pan pulled if it is clean then look into the controls being your problem. If there is any sign of damage pull the Transmission and repair as needed.
I would have the pan pulled if it is clean then look into the controls being your problem. If there is any sign of damage pull the Transmission and repair as needed.
