Circuit Description
The cruise control switch is an input to the engine control module (ECM). The ECM monitors the cruise control set/coast and resume/accelerate switch signal circuit in order to detect when a cruise control function has been requested. The ECM detects a specific voltage signal on the cruise control set/coast and resume/accelerate switch signal circuit when a cruise control function switch is activated, with each switch having a different predetermined voltage value.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0564 Cruise Control Multi-function Switch Circuit
Conditions for Setting the DTC
| • | The engine is running. |
| • | Ignition voltage is greater than 7.9956 volts. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
Diagnostic Aids
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Does the voltage measure at the specified value? | B+ | Go to Step 3 | Go to Step 7 |
3 |
Does the cruise control function switch resistance values measure between the specified values? | Switch On = ∞ Ω Switch Off = 0 Ω | Go to Step 4 | Go to Step 5 |
4 | Test the cruise control set/coast and resume/accelerate switch signal circuit for a high resistance, a short to voltage, or a short to ground between the cruise control switch and the engine control module (ECM). Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 |
5 | Inspect for poor connections at the connector of the multifunction switch. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
6 | Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
7 | Repair the high resistance in the ignition 1 voltage circuit. Did you complete the repair? | -- | Go to Step 10 | -- |
8 | Once the replacement is complete verify the repair. Did you complete the repair? | -- | Go to Step 10 | -- |
9 | Replace the ECM. Refer to Control Module References for ECM replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 2 | -- |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
