GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

    â€¢ The wait to start indicator illuminates only with the ignition ON and the engine OFF. The wait to start indicator will not illuminate during post-start glow plug operation.
    â€¢ The wait to start indicator will not stay ON for long at higher engine temperatures.

Step

Action

Yes

No

Schematic Reference: Driver Information System Schematics

Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views or Engine Control Module Connector End Views

1

Did you perform the Instrument Cluster Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Turn the ignition ON, with the engine OFF.
  2. Observe the wait to start indicator in the message center.

Does the wait to start indicator illuminate in the message center and then turn OFF?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Does the wait to start indicator illuminate continuously in the message center?

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn the ignition OFF.
  2. Disconnect the ECM.
  3. Turn the ignition ON, with the engine OFF.
  4. Observe the wait to start indicator in the message center.

Does the wait to start indicator illuminate continuously in the message center?

Go to Step 5

Go to Step 7

5

Test the wait to start indicator control circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the message center. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Replace the message center. Refer to Telltale Circuit Board Replacement .

Did you complete the replacement?

Go to Step 10

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9

Important: Program the replacement ECM.

Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data in Engine Controls - 7.8L

Did you complete the replacement?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2