For 1990-2009 cars

### Circuit Description

The cruise control switch is an input to the powertrain control module (PCM). The PCM 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 PCM 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 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 PCM detects an invalid voltage signal on the cruise control set/coast and resume/accelerate switch signal circuit for greater than 1.5 seconds.

The PCM runs this diagnostic every 0.05 seconds.

### Action Taken When the DTC Sets

• | The PCM stores the DTC information into memory when the diagnostic runs and fails.

• | The malfunction indicator lamp (MIL) will not illuminate.

• | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

• | The Cruise Control System is disabled.

### Conditions for Clearing the 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 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: Master Electrical Component List
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn ON the ignition, with the engine OFF.
2. With a DMM, measure the voltage of the ignition 1 voltage circuit at the back of C204.

Does the voltage measure at the specified value?

B+

Go to Step 3

Go to Step 7

3 | Important: The cruise control on/off switch must be turned ON in order to correctly view the set/coast switch resistance value with the DMM.

1. Turn OFF the ignition.
2. Disconnect C204.
3. With a DMM, measure the resistance of the cruise control switch between the ignition 1 voltage circuit and the cruise control set/coast and resume/accelerate switch signal circuit.
4. Individually activate and hold the cruise control function switches while measuring the resistance of the cruise control function switches.

Does the cruise control function switch resistance values measure within the specified values?

Off = O.L.

On = 7.8 K ohms - 8.6 K ohms

Resume = 2.7 K ohms - 3.0 K ohms

Set = 1.2 K ohms - 1.3 K ohms

Go to Step 4

Go to Step 5

4 | Test the cruise control set/coast and resume/accelerate switch signal circuit between the cruise control switch and the powertrain control module (PCM) for the following:

• | A high resistance

• | A short to voltage

• | A short to ground

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 6

5 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | -- | Go to Step 10 | --
8 | Replace the cruise control switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the replacement? | -- | Go to Step 10 | --
9 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 10 | --
10 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

--

Go to Step 2

System OK