P1580

DTC P1580

CIRCUIT DESCRIPTION




By pulse width modulating (PWM) the Cruise Control Servo Move Signal circuit the engine control module (ECM) indicates to the cruise control module how much accelerator pedal movement is necessary. The amount of pedal movement is determined by the duty cycle of the PWM signal, which is sent every 100 ms. DTC 1580 sets when Cruise Control Servo Move Signal circuit is commanded high, PWM is ON, and the voltage level at the ECM is low.

CONDITIONS FOR RUNNING THE DTC
Continuously when the engine is running.

CONDITIONS FOR SETTING THE DTC
- The ECM detects low feedback voltage when the Cruise Control Servo Move Signal circuit is commanded high.
- The condition exists for 500 ms.

ACTION TAKEN WHEN THE DTC SETS
- The ECM stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.

CONDITIONS FOR CLEARING THE DTC
- A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
- A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Use a scan tool in order to clear the DTC.

DIAGNOSTIC AIDS

IMPORTANT: To locate an intermittent problem, use the scan tool to monitor the C/C MOVE CKT. -LOW VOLT test with the ignition ON, and the engine OFF. The scan tool will display Test Fail when a short to ground exists in the Cruise Control Servo Move Signal circuit.

TEST DESCRIPTION

Steps 1-7:

The number below refers to the step number on the diagnostic table.
2. This step determines if the fault is present.