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.

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 system 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 in Wiring Systems.

Step

Action

Values

Yes

No

Schematic Reference : Cruise Control Schematics

Connector End View Reference: Cruise Control Connector End Views or to Engine Control Module Connector End Views in Engine Controls - 3.6L (LY7)

1

Did you perform the Cruise Control Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Cruise Control

2

  1. Turn OFF the ignition.
  2. Disconnect C4 of the cruise control switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a DMM, measure the voltage of the cruise control set/coast and resume/accelerate switch signal circuit between C4 and the engine control module (ECM).

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 in Wiring Systems.

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 5

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 in Wiring Systems.

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 in Wiring Systems.

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 in Steering Wheel and Column.

Did you complete the replacement?

--

Go to Step 9

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8

Important: Program the replacement ECM.

Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 3.6L (LY7).

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 Running the DTC.

Does the DTC reset?

--

Go to Step 2

System OK