P1581

DTC P1581

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 OFF (PWM is OFF) and the voltage level at the ECM is high.

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 OFF.
- 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
- To locate an intermittent problem, use the scan tool to monitor the C/C Move Ckt. -High Volt and C/C Move Ckt.-Open tests with ignition ON, engine OFF The scan tool will display Test Fail when a short to voltage or open exists in the Cruise Control Servo Move Signal circuit.
- Loss of ground for the cruise control module can cause this DTC to set. If this condition exists DTC P01583 and P1587 will also set.

TEST DESCRIPTION

Steps 1-9:

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