GM Service Manual Online
For 1990-2009 cars only

Object Number: 668172  Size: SF
Handling ESD Sensitive Parts Notice
Engine Controls Components
Cruise Control
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The engine control module (ECM) turns the CRUISE lamp ON whenever actual cruise operation is present. The ECM controls the lamp by grounding the control circuit with an internal solid state device called a driver.

Conditions for Running the DTC

    • The battery voltage is between 7.5-15 volts.
    • The engine speed is more than 40 RPM.
    • The cruise control is engaged.

Conditions for Setting the DTC

An open, a short to voltage, or a short to ground is monitored by the ECM.

Action Taken When the DTC Sets

The ECM will not illuminate the malfunction indicator lamp (MIL).

Conditions for Clearing the MIL/DTC

    • The diagnostic trouble code (DTC) clears after 40 consecutive warm up cycles in which no failures are reported by this diagnostic or any other non-emission related diagnostic.
    • The scan tool clears the MIL/DTC.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. The CRUISE lamp should remain OFF when the ignition is turned ON and the engine is OFF.

  2. If the other indicator lamps in the instrument cluster are functioning, the feed circuit is OK.

  3. If the CRUISE lamp is ON with the ECM connected and OFF with the ECM disconnected there is a problem in the ECM.

    If the CRUISE lamp is OFF with the ECM disconnected and a short to ground is NOT present on the control circuit the fault is within the instrument panel.

  4. After cruise is engaged, the CRUISE indicator lamp should illuminate.

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Turn ON the ignition, leaving the engine OFF.

Is the CRUISE indicator OFF?

--

Go to Step 3

Go to Step 6

3

Check the fuse for the instrument cluster ignition feed circuit.

Is the fuse OK?

--

Go to Step 4

Go to Step 9

4

  1. Turn OFF the ignition.
  2. Disconnect the ECM.
  3. Turn ON the ignition.
  4. Use a fused jumper in order to jumper the CRUISE indicator control circuit in the ECM harness connector to ground.

Is the CRUISE indicator ON?

--

Go to Step 10

Go to Step 5

5

Check for the following conditions:

    • A damaged bulb--Refer to Instrument Cluster Indicator Lamp Replacement in Instrument Panel, Gauges and Console.
    •  An open ignition feed to the bulb--Refer to Wiring Repairs in Wiring Systems.
    • A control circuit open or shorted to B+--Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 12

--

6

Command the CRUISE indicator OFF using the scan tool.

Does the CRUISE indicator turn OFF?

--

Go to Step 11

Go to Step 7

7

  1. Turn OFF the ignition.
  2. Disconnect the ECM.
  3. Turn ON the ignition with the engine OFF.

Is the CRUISE indicator ON?

--

Go to Step 8

Go to Step 10

8

Repair the short to ground in the CRUISE control circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 12

--

9

Repair the short to ground in the feed circuit to the instrument panel indicator lamps. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 12

--

10

Check for a poor connections or poor terminal tension at the ECM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct a problem?

--

Go to Step 12

Go to Step 11

11

Important: 

   • Perform the Idle Learn Procedure when replacing the ECM or the throttle body.
   • This vehicle is equipped with a theft deterrent system that interfaces with the ECM. Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle.

Replace the ECM. Refer to Engine Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 12

--

12

  1. Using the scan tool, clear the DTCs.
  2. Operate the vehicle within the Conditions for Running this DTC.
  3. Operate the vehicle with cruise engaged.

Does the scan tool indicate that the diagnostic Passed?

--

System OK

Go to Step 2