Circuit Description
The traction control system (TCS) uses the anti-lock brakes, and the PCM to control the amount of torque to the drive wheels. The PCM reduces the engine torque by any or all of the following means:
| • | Retarding spark timing. |
| • | Altering air/fuel ratio. |
| • | Turning OFF fuel injectors. |
The PCM applies approximately 5 volts to the EBCM via the Requested Torque circuit. The EBCM provides the PCM with a PWM signal by grounding the circuit. The PCM uses the PWM signal to determine the amount of torque reduction needed. With traction control not active, the requested torque should vary between 95 percent and 100 percent. If the PCM detects a PWM signal outside the normal operating range, DTC P1571 will set.
Conditions for Running the DTC
| • | DTC P1602 not set. |
| • | Traction control not failed. |
| • | Engine speed more than 500 RPM for 20 seconds. |
Conditions for Setting the DTC
The PCM does not detect a signal on the desired torque circuit 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. |
| • | 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. |
| • | A last test failed (Current DTC) will clear when the diagnostic runs and does not fail. |
| • | Use a scan tool in order to clear the MIL/DTC. |
| • | Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Powertrain Control Module (PCM) , Clearing Diagnostic Trouble Codes. |
Diagnostic Aids
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 the condition is intermittent, refer to Intermittent Conditions in Symptoms.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||||||||
2 |
Does the scan tool indicate that DTC P1571 failed last test? | -- | Go to Diagnostic Aids | |||||||
3 |
Does the DMM indicate a voltage within the specified value? | 3.8V-4.3V | ||||||||
4 |
Did you find and correct the condition? | -- | Go to Electronic Brake Control Module Replacement in Antilock Brake System | |||||||
5 | Does the DMM display a voltage? | -- | ||||||||
6 |
Did you find and correct the condition? | -- | ||||||||
7 |
Did you find and correct the condition? | -- | ||||||||
8 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |||||||
9 |
Does the scan tool indicate that DTC P1571 passed? | -- | System OK |
