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 P0581 Cruise Control Multifunction Switch High Voltage
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The cruise control on/off switch is ON. |
Conditions for Setting the DTC
This DTC sets when the ECM detects that the voltage on the cruise control set/coast and resume/accelerate switch signal circuit is greater than 3.5 volts for greater than 1.5 seconds.
The ECM runs this diagnostic every 0.05 seconds.
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. |
| • | The cruise control is disabled. |
Conditions for Clearing the MIL/DTC
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL/DTC. |
Diagnostic Aids
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views , Engine Control Module Connector End Views for the 2.8L engine, or Engine Control Module Connector End Views for the 3.6L (LY7) engine | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Does the voltage measure at or greater than the specified value? | 3.5 V | Go to Step 3 | Go to Step 4 |
3 | Test the cruise control set/coast and resume/accelerate switch signal circuit for a short to voltage between C4 and the ECM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6 |
4 | Test the cruise control set/coast and resume/accelerate switch signal circuit for a short to voltage between C4 and the cruise control switch. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 5 |
5 | Inspect for poor connections at C4 of the multifunction switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
7 | Replace the cruise control switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
