GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Component Connector End Views

1

Did you review the Instrument Cluster Diagnostic Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Instrument Cluster Description and Operation

2

  1. Install a scan tool.
  2. Start the engine.
  3. With the scan tool, observe the Engine Speed parameter in the Engine Data list.

Does the Engine Speed parameter match the tachometer display?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Using a multimeter, inspect the instrument panel cluster (IPC) engine speed output circuit cavity 27 for 6.5-7V. Refer to Testing for Intermittent Conditions and Poor Connections .

Is voltage within specified value?

Go to Step 6

Go to Step 4

4

Using a multimeter, inspect the powertrain control module (PCM) engine speed output circuit connector 4 cavity 5 (C3 cavity 3 LNK) for 6.5-7V. Refer to Testing for Intermittent Conditions and Poor Connections .

Is voltage within specified value?

Go to Step 5

Go to Step 7

5

Repair the open or high resistance in the engine speed output circuit between the PCM and the instrument cluster . Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 8

--

6

Replace the instrument cluster. Refer to Instrument Cluster Replacement .

Did you complete the replacement?

Go to Step 8

--

7

Replace the PCM. Refer to Control Module References .

Did you complete the replacement?

Go to Step 8

--

8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2