ABS warning in REVERSE ONLY EVERY TIME
once I back out the driveway, I shut off the car, clear the message and restart it and all is fine until I need to back up again.
anyone have this issue, any ideas or directions to look for the problem. I have done all the wiring to ground checks/cleaning etc.
car is a 97 coupe, 6 speed. thanks in advance. tom





READING YOUR Engine Diagnostic Codes (DTCs)
The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open etc…)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.
Initially, on-board diagnostics go into an Automatic Mode which shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each. ( i.e. PCM = 4 codes)
If none are present in a given module, you will see No More Codes on the display.
There are two kinds of diagnostic codes, Current and History designated with a letter suffix, C or ;H. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes.
More likely it's an indication of an intermittent malfunction.
Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.
Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present;
press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET
To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles.
Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.
Here is very good site of DTC definitions:
http://www.gearchatter.com
Make sure to include the H or C suffix!!
10PCM 1571 H C traction control torque request circuit
28TCS C1225 H LF Excessive wheel speed variation
60 IPC U1160 H
B) RFA C2110 H C could not find description
C2115 H C could not find description
any short check listings to troubleshoot this issue
any assistance will be GREATLY appreciated.








The wheel speed sensors dont care what direction the car goes. They still output an AC voltage.
Looks like the sensors worked fine. What tripped the alarm was:
- 10PCM 1571 H C traction control torque request circuit
DTC P1571 Traction Control Torque Request Circuit
Circuit Description
The PCM supplies 5.0 volts on the Desired Torque circuit to the Electronic Brake and Traction Control Module (EBTCM). The EBTCM toggles this 5.0 volt signal to a ground in order to produce a duty cycle signal. The signal is proportional to the amount of engine output torque reduction requested by the EBTCM. The EBTCM supplies this signal when it detects a wheel slip. In order to reduce engine output torque, the PCM reduces the amount of spark advance and in some cases the PCM disables a number of fuel injectors. This diagnostic test checks for a Desired Torque signal failure. If the PCM does not receive the Desired torque signal this DTC sets.
Conditions for Setting the DTC
The traction control has not failed.
The engine speed is greater than 500 RPM for 20 seconds.
The desired torque signal is not received by the PCM for 3 seconds.
Action Taken When the DTC Sets
The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.
The malfunction indicator lamp (MIL) will not illuminate.
The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
Conditions for Clearing the MIL/DTC
A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the MIL/DTC.
Diagnostic Aids
Important
Do not perform this diagnostic procedure if the customer's concern is not related to the ABS and/or the Traction Control system(s).
The following may cause an intermittent:
Mis-routed harness
Rubbed through wire insulation
Broken wire inside the insulation
Test Description
The numbers below refer to the step numbers on the diagnostic table.
This step determines if the EBTCM is receiving the 5.0 volts from the PCM. Use the connector test kit adaptor J 35616-A when probing the EBTCM connector.
If no DTCs are set, inspect connections at the EBTCM.
This DTC will not report a pass. The scan tool status for this DTC will never report a pass. The scan tool will only display when the diagnostic fails. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.
DTC P1571 Desired Torque Circuit Step
Action
Value(s)
Yes
No
1
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check
2
Important
Perform this diagnostic procedure only if the customer's concern is related to the ABS and/or the Traction Control system(s). Refer to ABS Diagnostic System Check for further diagnosis.
Install the scan tool.
Turn OFF the ignition.
Disconnect the EBTCM electrical connector.
Turn ON the ignition leaving the engine OFF.
Probe the Desired Torque circuit at the EBTCM electrical connector using the DMM J 39200 connected to ground.
Does the DMM display near the specified value?
5.0 V
Go to Step 3
Go to Step 4
3
Important
Verify communication between the scan tool and the EBTCM before you continue with this diagnostic. Refer to ABS Diagnostic System Check if you can not establish communications.
Are DTCs C1255 or C1277 (ABS/TCS DTCs) or B0844 (BCM DTC) set?
--
Go to Brakes or Body and Accessories for further diagnosis
Condition intermittent, Go to Diagnostic Aids
4
Probe the Desired Torque circuit at the EBTCM electrical connector using the DMM J 39200 connected to ground.
Does the DMM display near the specified value?
B+
Go to Step 7
Go to Step 5
5
Probe the Desired Torque circuit at the EBTCM electrical connector using a test lamp connected to B+.
Is the test lamp illuminated?
--
Go to Step 8
Go to Step 6
6
Check for an open in the Desired Torque circuit.
If you find a problem, repair it as necessary. Refer to Body and Accessories/Wiring Systems.
Did you find and correct the condition?
--
Go to Step 11
Go to Step 9
7
Repair the short to B+ on the Desired Torque circuit. Refer to Body and Accessories/Wiring Systems.
Is the action complete?
--
Go to Step 11
--
8
Repair the short to ground on the Desired Torque circuit. Refer to Body and Accessories/Wiring Systems.
Is the action complete?
--
Go to Step 11
--
9
Check the terminal connections at the PCM.
If you find a problem, repair it as necessary. Refer to Body and Accessories/Wiring Systems.
Did you find and correct the condition?
--
Go to Step 11
Go to Step 10
10
Important:
Program the replacement PCM. Refer to PCM/TAC Module Replacement .
Replace the PCM.
Is the action complete?
--
Go to Step 11
--
11
Select the Diagnostic Trouble Code (DTC) option and the Clear DTC option using the scan tool.
Idle the engine at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
Operate vehicle within the conditions for setting this DTC as specified in the supporting text, if applicable.
Does the scan tool indicate that this test failed?
--
Go to Step 12
Go to Step 2
12
Select the Capture Info option and the Review Info option using the scan tool.
Does the scan tool display any DTCs that you have not diagnosed?
--
Go to applicable DTC
System OK
--------------------------------------------------------------------------------
Document ID# 101551
1997 Chevrolet/Geo Corvette
Your missing DTC would not trip this issue and it is:
DTC C2115 Left Rear TPM Sensor Malfunction
Circuit Description
When the TPM sensors detect a vehicle speed of 16-24 km/h (10-15 mph), the TPM sensors will enter a powered up stage and begin to transmit a unique identification code and tire pressure information from 0-437 kPa (0-62 psi) to the receiver. The receiver waits for the first sensor to transmit information. When the first sensor transmits its information 15 times, the receiver checks whether all sensors have sent their information. If one or more sensors do not transmit information, the receiver will set the appropriate DTCs for the TPM sensor that did not transmit. When the vehicle has been stationary for more than 1 minute, the sensor will enter a power down or sleep mode and will stop transmitting tire pressure information.
Conditions for Setting the DTC
The vehicle completes a diagnostic cycle (driving for about 20 minutes at speeds over 24 km/h [15 mph]) and the left rear TPM sensor has not transmitted tire pressure information.
The receiver has received at least one TPM sensor transmit tire pressure information 15 times and no tire pressure information was received from the left rear TPM sensor.
Action Taken When the DTC Sets
Stores a DTC C2115 in the receiver memory
Sends a message to the IPC to display the SERVICE TIRE WARN SYS message
The IPC will default to display the left rear tire pressure as XXX kPa (XX psi).
Conditions for Clearing the DTC
The left rear TPM sensor transmits tire pressure information to the receiver before a diagnostic cycle is completed.
A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
Use the IPC clearing DTCs feature.
Use a scan tool.
Diagnostic Aids
The IPC will default to display the left rear tire pressure as XXX kPa (XX psi) if the receiver is unable to receive or send tire pressure data.
If there is an open in the serial data line to the receiver, the IPC will display XXX kPa (XX psi) for all tire pressure values and the SERVICE TIRE WARN SYS message.
Clear the receiver diagnostic memory before road testing the vehicle whenever a TPM sensor is replaced in order to avoid reading the original DTC stored in the memory.
Take tire pressure measurements when the tires are cold in order to obtain the lowest readings.
Test Description
The numbers below refer to the Step numbers on the diagnostic table:
This test checks if the IPC can enter the TIRE TRAINING mode. If the display is blank, or if the DIC buttons do not respond when pressed, the IPC must be diagnosed first.
This test determines if the TPM sensors can properly transmit their identification codes. (If the horn did not sound during the test, the receiver was unable to receive a TPM sensor identification code.)
This test determines if the TPM sensor replacement corrected the malfunction.
This test determines if programming the TPM sensors corrected the malfunction.
DTC C2110 -- Right Rear TPM Sensor Malfunction Step
Action
Value(s)
Yes
No
1
Were you sent here from the TPM Diagnostic System Check?
--
Go to Step 2
Go to Diagnostic System Check - Tire Pressure Monitoring
2
Using the buttons on the DIC, enter the TIRE TRAINING mode. Refer to Tire Pressure Monitoring Sensor Programming .
Can the programming be successfully accessed through the IPC?
--
Go to Step 3
Go to IPC Diagnostic System Check
3
Program all TPM sensors. Refer to Tire Pressure Monitoring Sensor Programming .
Was the right rear TPM sensor programming successful?
--
Go to Step 6
Go to Step 4
4
Replace the right rear TPM sensor. Refer to Tire Pressure Monitoring Sensor Programming .
Program all the TPM sensors. Refer to Tire Pressure Monitoring Sensor Programming .
Is the replacement complete?
--
Go to Step 5
--
5
Clear the DTCs. Refer to Clearing DTCs .
Road test the vehicle above 24 km/h (15 mph) for 20 minutes.
Does DTC C2110 reset?
--
Go to Step 7
System OK
6
Clear the DTCs. Refer to Clearing DTCs .
Road test the vehicle above 24 km/h (15 mph) for 20 minutes.
Does DTC C2110 reset?
--
Go to Step 4
System OK
7
Replace the remote control door lock receiver. Refer to Tire Pressure Monitoring Receiver .
Program all TPM sensors. Refer to Tire Pressure Monitoring Sensor Programming .
Program the RFA transmitters. Refer to Transmitter Programming/Synchronization in Keyless Entry.
Is the replacement complete?
--
Go to Step 8
--
8
Turn the ignition to OFF.
Install any components or connectors that were removed.
Clear all DTCs. Refer to Clearing DTCs .
Are the repairs complete?
--
Go to Diagnostic System Check - Tire Pressure Monitoring
--
--------------------------------------------------------------------------------
Document ID# 189881
1997 Chevrolet/Geo Corvette
Thanks for the reply...unfortunately rides are hard to obtain today as the requested units are out of production and pretty much obsolete. Some still exist but are very very expensive to enjoy.
I have the FSM and will try to tackle some trouble shooting this holiday weekend.
I have sent you an email in case your schematic would be different than the FSM.
Thanks tom.






