P1571

Circuit Description
The PCM supplies 5 volts on the desired torque circuit to the Electronic Brake and Traction Control Module (EBTCM). The EBTCM toggles this 5 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 tests for a Desired Torque signal failure. If the PCM does not receive the Desired torque signal, this DTC sets.

Conditions for Running the DTC
^ The traction control has not failed.
^ The engine speed is greater than 500 RPM for 20 seconds.

Conditions for Setting the DTC
The desired torque signal is not received by the PCM for 3 seconds.

Action Taken When the DTC Sets
^ The 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 (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the MIL/DTC.

Diagnostic Aids

Important:
^ Remove any debris from the PCM/TAC module connector surfaces before servicing the PCM/TAC module. Inspect the PCM/TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM/TAC modules.
^ For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A. Using this kit prevents damage to the harness/component terminals.
^ 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:
- Poor connections
- Corrosion
- Mis-routed harness
- Rubbed through wire insulation
- Broken wire inside the insulation
^ For an intermittent condition, refer to Symptoms. Symptom Related Diagnostic Procedures

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the EBTCM is receiving the 5 volts from the PCM. Use the connector test kit adaptor J 356f6-A when probing the EBTCM connector.
3. if no DTCs are set, inspect connections at the EBTCM.