LEMON Manuals: Even more car manuals for everyone
Home >> Cadillac >> 2006 >> XLR Base >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel System Displays, Gauges And Console >> Diagnostic Information and Procedures >> Tachometer Inaccurate or Inoperative

Tachometer Inaccurate or Inoperative

Tachometer Inaccurate or Inoperative

Step Action Values Yes No
Schematic Reference: Instrument Cluster Schematics 
Connector End View Reference: Engine Control Module Connector End Views for the 4.4L engine or Engine Control Module Connector End Views for the 4.6L engine
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  1. Install a scan tool.
  2. Start the engine.
  3. With the scan tool, observe the Engine Speed parameter in the engine control module (ECM) Engine Data 1 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
  1. Turn OFF the ignition.
  2. Disconnect the ECM connector C1.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the engine speed signal circuit to a good ground.
Does the voltage measure greater than the specified value?
9 V Go to Step 5  Go to Step 4 
4 Test the engine speed signal circuit for the following:
  • An open
  • High resistance
  • A short to ground

Refer to Circuit Testing and to Wiring Repairs .
Did you find and correct the condition?
- Go to Step 10  Go to Step 6 
5 Test the engine speed signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs .
Did you find and correct the condition?
- Go to Step 10  Go to Step 7 
6 Inspect for poor connections at the harness connector of the instrument panel cluster (IPC). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .
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 .
Did you find and correct the condition?
- Go to Step 10  Go to Step 9 
8 Replace the IPC. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?
- Go to Step 10  -
9 Replace the ECM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?
- Go to Step 10  -
10 Operate the system in order to verify the repair.
Did you correct the condition?
- System OK Go to Step 2