Circuit Description
The cruise control clutch is used to engage and release the cruise control cable drive mechanism from the cruise control motor. To command the clutch ON, engaged, the engine control module (ECM) provides ground to the cruise control module via the Cruise Control Servo Clutch Control circuit. When the cruise control clutch is commanded OFF, disengaged, the feedback voltage at the ECM should be high. If the cruise control clutch is commanded OFF, and the feedback voltage on the Cruise Control Servo Clutch Control circuit is low, DTC P1587 will set indicating a short to ground or open exists.
Conditions for Running the DTC
Continuous when cruise control clutch commanded OFF, disengaged.
Conditions for Setting the DTC
| • | The ECM detects low feedback voltage when the cruise control clutch 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 Clutch-Low Volt and C/C Clutch-Open tests with ignition ON, engine OFF. The scan tool will display Test Fail when a short to ground or open exists in the Cruise Control Servo Clutch Control circuit. |
| • | Loss of ground for the cruise control module can cause this DTC to set. If this condition exists DTC P01581 and P1583 will also set. |
| • | Loss of ignition voltage for the cruise control module can also set this DTC. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Connector End View Reference: Cruise Control Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Cruise Control? | Go to Step 2 | |
Does the Test Fail? | Go to Step 3 | Go to Diagnostic Aids | |
3 |
Does the test light illuminate? | Go to Step 4 | Go to Step 6 |
4 |
Does Test Fail? | Go to Step 5 | Go to Step 7 |
5 | Inspect Cruise Control Servo Clutch Control circuit for short to ground or open circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the problem? | Go to Step 9 | Go to Step 8 |
6 | Inspect the ignition 1 voltage circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the problem? | Go to Step 9 | -- |
7 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Did you complete the repair? | Go to Step 9 | -- |
8 |
Important: The replacement ECM must be programmed. Replace ECM. Refer to Engine Control Module Replacement in Engine Controls. Did you complete the repair? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |
