Pinpoint Test F: The Tachometer Is Inoperative

F1 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND PCM SELF-TESTS
- Check for recorded PCM DTCs from the continuous and on-demand self-tests.
- Are any PCM DTCs recorded?
1. YES : REFER to the Introduction - Gasoline Engines article to continue diagnosis of the DTCs.
2. NO : Go to F2.
F2 CARRY OUT THE INSTRUMENT CLUSTER TACHOMETER GAUGE ACTIVE COMMAND USING THE SCAN TOOL
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster Active Command
- Select the instrument cluster tachometer TACH active command. Scroll the tachometer in 3 segments: 0%, 50% and 100%. Observe the tachometer.
- Does the tachometer start at 0 rpm, move to about 3,000 rpm and move to 6,000 rpm?
1. YES : Go to F3.
2. NO : Go to F4.
F3 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS article. TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
F4 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
- Disconnect the instrument cluster connector.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect the instrument cluster connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new instrument cluster. REFER to Instrument Cluster . TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.