P1644

CIRCUIT DESCRIPTION

Schematic:

The Electronic Brake And Traction Control Module (EBCM) controls the PWM signal on the Desired Torque circuit while monitoring the wheel speed sensors to detect slippage. The PCM monitors the PWM signal and reduces engine torque as needed. The PCM sends a Delivered Torque PWM signal in response to the Desired Torque PWM signal from EBCM. If the PCM detects an improper circuit condition in the Delivered Torque circuit, DTC P1644 will set. The EBCM will disable traction control when the DTC sets. An ABS/TCS DTC may also be set. For further traction control information, refer to ABS/TCS.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
^ An improper voltage level has been detected on the Delivered Torque Circuit.
^ The conditions exists for at least 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store the conditions present when the DTC set as Fail Records data only.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
If the condition is intermittent, refer to Intermittent Conditions in Symptoms. Intermittent Conditions

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