I just recently took my '95 vette to sears to get an oil change and to get the serpentine belt replaced. The guy ended up breaking my coolant temp sensor but he replaced it and i was off on my way. I polished her up and it back in the garage without a problem. Two days later i took it out for a short drive and all hell broke loose. The engine started idling erratically, i freaked out and try to get it home as fast as possible. I cleaned the plugs and changed the fuel filter but the problem keeps getting worse. I tried tinkering with it today and the check engine light came on. I tried taking it to AutoZone only for them to tell me that they can't scan my car. Does anyone have i clue as to what i should do next? How do i figure out what the code is if i can't scan it?

 

My first thought is to check to make sure the belt was put on properly. It wouldn't be too hard to get it wrong. One pulley going the wrong way would give everything fits. If this is good, my second thought is the opti. Is there any way it got wet? Or perhaps when the tech was in there he knocked one of the wires loose?

 

On a 94/95 you can check the codes with a paper clip as follows:

You short pin "12" to pin "4" and turn the ignition switch to "On" without starting the engine.

The speedometer will display any codes using the same protocol as the 1990-1993 model but there are some changes in the designation for the modules plus additional modules are added:

Module "1" is still the CCM module.

Module "4" is now called the PCM module (Powertrain Control Module) because automatic transmission computer control was added to Engine Control Module in 1994.

Module 7 (on the 1996 model only) is the RTD module. (This is the Real Time Dampening module which replaced the Selective Ride Control module in 1996).

Module 9 is the ABS/ASR module number from 1994 through 1996.
Finally, Module "A", the DERM (Dynamic Energy Control Module --- (the air bag control module) will be requested to show any codes.

Just like the 1990-1993 display, you read the codes on the speedometer (big) and read the module number on the trip odometer (small).

A series of dashed lines for instance “ - - -“ indicates no more stored codes for that module.

A code showing as “C12” for the CCM module (module #1) means no codes are stored. So C12 is a good thing to see.

Again, you can cause the codes to repeat by turning the ignition off for five seconds and then back on.

Turn the ignition off and remove the short to restore normal operation.

To clear the codes,

1. With ignition "off" ground terminal #12 of the DLC (use bent paper clip to connect pin 4 to pin 12)

2. Turn ignition "on".

3. Press trip/odo button on the DIC until 1.7 appears in the trip
monitor area of the instrument cluster.

4. Press eng/met button on the DIC & hold until "---" appears in the
speedometer area of the cluster, this will clear CCM DTC'S.


To clear PCM/ECM codes do the following:


1. Press the trip reset button on the DIC until the desired system is displayed. In this case it will be 4.0.

2. Press trip/odo button on the DIC until the desired diagnostic mode(4.7) is displayed on the trip monitor area of the cluster.

3. Press & hold the eng/met button on the DIC until "---" is
displayed in the speedometer area of the cluster, this will clear PCM codes.


To clear ABS/ASR codes do the following:

Same as above but you’re looking for “9.7” on the trip odo

And here are the codes

1994-1995: Diagnostic Trouble Codes
DTC #11: Malfunction Indicator Lamp Circuit.
DTC #13: Bank #1 Heated Oxygen Sensor #1 Circuit:
DTC #14: Engine Coolant Temperature Sensor Circuit Voltage Low.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High.
DTC #16: Distributor Ignition System Low Pulse.
DTC #18: Injector Circuit.
DTC #21: Throttle Position Sensor Circuit Voltage High.
DTC #22: Throttle Position Sensor Circuit Voltage Low.
DTC #23: Intake Temperature Sensor Circuit Voltage High.
DTC #24: Vehicle Speed Sensor Circuit.
DTC #25: Intake Air Temperature Sensor Circuit Voltage Low.
DTC #26: Evaporative Emission Canister Purge Solenoid Valve Circuit.
DTC #27: EGR Vacuum Control Signal Solenoid Valve Circuit.
DTC #28: Transmission Range Pressure Switch Assembly Fault.
DTC #29: Secondary Air Injection Pump Circuit.
DTC #32: Exhaust Gas Recalculation.
DTC #33: Manifold Absolute Pressure Sensor Circuit High.
DTC #34: Manifold Absolute Pressure Sensor Circuit Low.
DTC #36: Distributor Ignition System High Pulse.
DTC #37: Brake Switch Stuck On.
DTC #38: Brake Switch Stuck Off.
DTC #41: Ignition Control Circuit Open.
DTC #42: Ignition Control Circuit Shorted.
DTC #43: Knock Sensor Circuit.
DTC #44: Bank 1 LF Heated Oxygen Sensor #1 Circuit Lean.
DTC #45: Bank 1 LF Heated Oxygen Sensor #1 Circuit Rich.
DTC #47: Knock Sensor Circuit Or Module Missing.
DTC #48: Mass Air Flow Sensor Circuit.
DTC #50: System Voltage Low.
DTC #51: EPROM Programming Error.
DTC #52: Engine Oil Temperature Sensor Circuit Voltage Low.
DTC #53: System Voltage Low.
DTC #55: Fuel Lean Monitor.
DTC #58: Transmission Fluid Temperature Sensor Circuit Low.
DTC #59: Transmission Fluid Temperature Sensor Circuit High.
DTC #62: Engine Oil Temperature Sensor Circuit Voltage Low.
DTC #63: Bank 2 RF Heated Oxygen Sensor #1 Circuit Open.
DTC #64: Bank 2 RF Heated Oxygen Sensor #1 Circuit Lean.
DTC #65: Bank 2 RF Heated Oxygen Sensor #1 Circuit Rich.
DTC #66: A/C Refrigerant Pressure Sensor Circuit Open.
DTC #67: A/C Pressure Sensor Circuit Sensor or A/C Clutch.
DTC #68: A/C Relay Circuit.
DTC #69: A /C Clutch Circuit.
DTC #70: A/C Clutch Relay Driver Circuit.
DTC #72: Vehicle Speed Sensor Loss.
DTC #73: Pressure Control Solenoid Circuit Current Error.
DTC #74: Traction Control System Circuit Low.
DTC #75: Transmission System Voltage Low
DTC #77: Primary Cooling Fan Relay Control Circuit.
DTC #78: Secondary Cooling Fan Relay Control Circuit.
DTC #79: Transmission Fluid Overtemp.
DTC #80: Transmission Component Slipping.
DTC #81: Transmission 2-3 Shift Solenoid Circuit.
DTC #82: Transmission 1-2 Shift Solenoid Circuit.
DTC #83: Torque Converter Solenoid Voltage High.
DTC #84: 3-2 Control Solenoid Circuit.(Auto Only).
DTC #84: 2nd And 3rd Gear Blockout Relay Control Circuit.
DTC #85: Transmission TCC Stock On.
DTC #90: Transmission TCC Solenoid Circuit.
DTC #91: One To Four Upshift Lamp(Manual Only).
DTC #97: VSS Output Circuit.
DTC #98: Tachometer Output Signal Voltage Wrong.

 

Tell us what codes you get and module. I followed these codes on forum and cost me $40 in parts I didn't need.

 

It is possible the Sears monkey got the Opti wet when changing the coolant sensor. Check for codes as suggested, hopefully it will give you a starting point, but remember that DTC's only indicate the circuit affected, they do not indicate a part is bad. You will need the FSM to troubleshoot the code correctly.

 

Okay, I get a readout as follows.
1. C12 ---
4. H15 ---
9. ---
A. ---
1.0

 

What's my next step?

 

Check the plug on the coolant sensor clean it with electrical contact cleaner.The code indicates a problem with that sensor mabey the plug is not on all the way or the Sears guy broke it. By the way don't take your car to SWears to change the oil takes about 20 min do DIY the belt about 10 min.If you find the retainer clip is broken take it back to them and tell them to replace the plug.

 

first mistake: SEARS
but you knew that already
Even Chevroley is handicapped when it comes to these cars

 

Since it is a 95, it has the 'vented' OPTI, so less chance it was damaged by coolant.

What brand coolant sensor did the Sears guy install? If not an ACDelco it could be the sensor is just of poor quality.

What is the digital dash coolant temperature? Is it erratic or steady and consistent with your memory of how it was before being broken?

Also, how is the analog coolant temperature gauge? Is is reading about the same as the digital?

 

Where is this plug located?

 

My bet is they put the wrong sensor in, common problem w/shops who do not know vettes. You have 2 sensors and the plugs are the same or they might have broken the wire or knocked off some insulation(been there and done that) from the wire.

 

Just below the driver's side knee bolster, just above your right knee.

 

Is it easily visible? I feel like ive looked there before and havent found it.

 

While sitting in the drivers seat, reach under the dash and in front of your right knee. Easy to feel, harder to see.

 

When i unplug the coolant temp sensor, the vette purrs like a kitten. When i plug it back in, i get all of the problems that i spoke of before ( rough idling, problems accelerating, ect.) I would take it to sears to make him fix it but that didn't work out so well the last time so i think i'll do it myself.

 

Take it back to the shop that broke it and tell the manager you want it fixed.

 

I did take it back the last time the guy broke the sensor, he replaced it free of charge and i was on my way. The problems started soon after. I'd rather just do it myself this time to make sure it's done properly.

 

Go to your favorite auto parts place. Make sure they get you the CTS (coolant temperature sensor) that is on the waterpump - it is different than the one in the passenger head!

Look at the threads on the new sensor and see if it has sealent already on it.
If not get a small tube of the permatex (its white), use a good dose.

Drain the coolant, remove the old sensor, put the new sensor in, replace coolant, start up and check for leaks. It may take a couple tries to get the sensor seated so it doesn't leak.

You are done.