GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

An open or short to ground in the instrumtne panel (I/P) lamps dimmer switch signal can disable the PRNDL display. Check for DTC B2627 in Lighting Systems.

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Step

Action

Yes

No

Schematic Reference: Body Control System Schematics and Automatic Transmission Controls Schematics

Connector End View Reference: Computer/Integrating Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Is the shift indicator display inaccurate?

Go to Range Selector Displays Incorrect Range in Automatic Transaxle - AF3-5

Go to Step 3

3

  1. Turn the park lamps ON.
  2. Test the park lamp supply voltage circuit of the shift indicator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 4

4

Test the PRNDL/powertrain fuse supply voltage circuit of the shift indicator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 5

5

Test the ground circuit of the shift indicator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 6

6

Inspect for poor connections at the harness connector of the shift indicator. 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 8

Go to Step 7

7

Replace the shift indicator. Refer to Automatic Transmission Control Indicator Replacement in Automatic Transaxle - AF33-5.

Did you complete the replacement?

Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2