P1571

Diagnostic Chart:

Engine Controls Schematics: Cruise Control Module, EBCM and VSS:

CIRCUIT DESCRIPTION
This diagnostic test checks for a traction control system Desired Torque signal failure to the PCM. The PCM sends 5 volts on the Desired Torque circuit to the Electronic Brake And Traction Control Module (EBTCM). The EBTCM then rapidly switches this CKT to ground creating a Pulse Width Modulated (PWM) frequency signal to request a specific amount of torque reduction during a traction control event. If this PWM signal is not received by the PCM for 3 seconds, DTC P1571 is set.

CONDITIONS FOR RUNNING THE DTC
^ DTC P1602 is not set
^ The traction control has not failed
^ The engine speed is more than 500 RPM for 20 seconds.

CONDITIONS FOR SETTING THE DTC
A PWM frequency signal is not received on the Desired Torque circuit 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.
^ PCM disables first gear starts.
^ Transaxle shift adapts are maintained at current levels.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
^ The current DTC will clear when the diagnostic runs and does not fail.
^ Use a scan tool in order to clear the MIL diagnostic trouble code.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer Powertrain Control Module (PCM) Description clearing Diagnostic Trouble Codes.

DIAGNOSTIC AIDS

NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.

This DTC may set along with several others if the key is held in the Crank position while the engine is running. The starter lockout function of the PCM is enabled several seconds after the engine is running and will prevent the starter from engaging while the engine is running. This will cause a partial loss of power to some components and systems.

If no fault is present refer to A Diagnostic Starting Point in Antilock Brake System to aid in isolating an intermittent fault.

If the problem is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION
The number below refers to the step number on the diagnostic table.
3. Any frequency present indicates that the PCM is capable of modulating the circuit. The typical measured frequency is approximately 128 Hz at idle.