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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1570 (Instrument Panel, Gauges & Console) >> Diagnostic Information and Procedures >> Tachometer Inaccurate or Inoperative

Tachometer Inaccurate or Inoperative

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Tachometer Inaccurate or Inoperative

Step Action Yes No
Schematic Reference:  Instrument Cluster Schematics  
Connector End View Reference:  Instrument Panel, Gages, and Console Connector End Views  
1 Did you perform the Instrument Cluster Diagnostic System Check? Go to Step 2  Go toDiagnostic System Check - Instrument Cluster 
2
  1. Install a scan tool.
  2. Start the engine.
  3. With the scan tool, observe the Engine Speed parameter in the IPC Data 1 data list.
Does the Engine Speed parameter match the tachometer display?
Go to TESTING FOR INTERMITTENT CONDITIONS AND POOR CONNECTIONS in Wiring Systems Go to Step 3 
3 Test the engine speed signal circuit for a high resistance between the IPC and PCM. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems.
Did you find and correct the condition?
Go to Step 6  Go to Step 4 
4 Inspect for poor connections at the harness connector of the instrument cluster. 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 6  Go to Step 5 
5
IMPORTANT: Program the replacement IPC.
Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement .Did you complete the replacement?
Go to Step 6  -
6 Operate the system in order to verify the repair.
Did you correct the condition?
System OK Go to Step 2