GM Service Manual Online
For 1990-2009 cars only

Test Description

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

  1. This step ensures that the CRUISE indicator circuit is operational.

  2. Lack of communication may be due to a malfunction of the serial data circuit. The specified procedure will determine if the wire between the DLC and the cruise control module is intact.

Step

Action

Yes

No

1

  1. Locate the data link connector which is under the hood and mounted on the left strut tower.
  2. Connect a fused jumper wire between terminal Tc and terminal E1 of the underhood DLC.
  3. Turn ON the ignition, with the engine OFF.

Does the CRUISE indicator flash?

Go to Step 8

Go to Step 2

2

  1. Turn ON the ignition, with the engine OFF.
  2. Depress the cruise control On - Off switch to the On position.

Does the CRUISE indicator Illuminate?

Go to Step 3

Go to Cruise Control Indicator Inoperative

3

  1. Disconnect the cruise control module connector. Refer to Cruise Control Module Replacement for access.
  2. Measure for a high resistance or an open between cavity Tc of the DLC and cavity 5 of the cruise control module.

Did you test a high resistance or an open in the serial data line?

Go to Step 5

Go to Step 4

4

Inspect for poor connections at the harness connector of the cruise control module. 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 7

Go to Step 6

5

Repair the open in the serial data circuit between cavity Tc of the DLC and cavity 5 of the cruise control module. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 7

--

6

Replace the cruise control module. Refer to Cruise Control Module Replacement .

Did you complete the replacement?

Go to Step 7

--

7

  1. Connect a fused jumper wire between terminal Tc and terminal E1 of the underhood DLC.
  2. Turn ON the ignition, with the engine OFF.
  3. Note the flash code pattern.

Does the CRUISE indicator lamp flash rapidly?

Go to Symptoms - Cruise Control

Go to Diagnostic Trouble Code (DTC) List

8

Note the flash code pattern.

Does the CRUISE indicator lamp flash rapidly?

Go to Symptoms - Cruise Control

Go to Diagnostic Trouble Code (DTC) List