GM Service Manual Online
For 1990-2009 cars only

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

    •  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.
    • DTC(s) 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

Schematic Reference: Cruise Control Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn the ignition OFF.
  2. Disconnect the cruise control switch connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a DMM, measure the voltage of the ignition 1 voltage circuit.

Does the voltage measure at the specified value?

B+

Go to Step 3

Go to Step 7

3

  1. Turn OFF the ignition.
  2. With a DMM, measure the resistance of the cruise control switch between the connector terminal 1 and the terminal 4 respectively, while pressing the cruise control switch ON and OFF.

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 9

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 and Connector Repairs.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 6

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

Repair the high resistance in the ignition 1 voltage circuit.

Did you complete the repair?

--

Go to Step 9

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8

Replace the ECM. Refer to Control Module References.

Did you complete the replacement?

--

Go to Step 9

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9

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

Does the DTC reset?

--

Go to Step 2

System OK