P1571

DTC P1571 Electronic Brake And Traction Control Module (EBTCM) Diagnostic Chart:

Electronic Brake And Traction Control Module (EBTCM) Wiring Schematic:

CIRCUIT DESCRIPTION
The traction control system uses the antilock brake system in conjunction with the Powertrain Control Module (PCM), fuel and ignition controls to limit drive wheel slippage during acceleration. The PCM controlled portion of the traction control system reduces engine torque by any or all of the following methods.

^ Retarding spark timing.
^ Altering air/fuel ratio.
^ Altering boost duty cycle.
^ Shutting "OFF" up to three injectors.

To determine the amount of torque reduction required, the PCM monitors the desired torque Pulse Width Modulated (PWM) signal (CKT 463) from the Electronic Brake and Traction Control Module (EBTCM). The PCM also provides a delivered torque PWM signal (CKT 464) informing the EBTCM how much torque is being produced by the engine.

DIAGNOSTIC TROUBLE CODE (DTC) P1571 WILL SET WHEN
If the desired torque signal PWM duty cycle is below 5% or above 95%, DTC P1571 will set indicating a problem with the desired torque input on CKT 463.

ACTION TAKEN (PCM WILL DEFAULT TO)
With a current DTC P1571 set, the PCM will command the EBTCM via serial data (CKT 800) to set Antilock Brake System/Traction Control System (ABS/TCS) DTC 75, turn "OFF" traction control, and illuminate the "TRACTION OFF" lamp. DTC P1571 does not illuminate the Malfunction Indicator Lamp (MIL).

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks CKT 463 for an open or short to ground.
2. Ensures that the EBTCM is providing a proper PWM signal to the PCM on CKT 463.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.

Check for:
^ Poor connection or damaged harness - Inspect PCM harness for an open or short to ground in CKT 463 improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.
^ Intermittent test - Using a Digital Voltmeter (DVM) to ground observe voltage at PCM terminal "WCl3" while moving related connectors and wiring harness with warm engine running. If the failure is induced, the voltage will change. This may help to isolate the location of the malfunction.