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Tachometer Gauge Inoperative Or Inaccurate

  1. If other gauges operate normally, go to next step. If problems exist with other gauges, go to ALL GAUGES & INDICATORS (EXCEPT TURN SIGNALS, HIGH BEAM & SEAT BELT INDICATOR) INOPERATIVE  .
  2. Disconnect PCM connector C2. Turn ignition on. Check voltage between harness connector C2 terminal No. 8 (White wire) and ground. If 9-10 volts exists, go to next step. If 9-10 volts does not exist, go to step  4 .
  3. Turn ignition off. Reconnect PCM connector C2. Install scan tool. Using DVOM capable of reading Hertz, backprobe harness connector C2 terminal No. 8 (White wire) and connect other lead to ground. Start engine. Raise engine speed to 1000 RPM as observed on scan tool. If meter reading is 32-34 Hz, go to step  12 . If meter reading is not 32-34 Hz, go to step  13 .
  4. Check voltage (backprobe) between ground and underhood accessory wiring junction block connector C1 terminal F6 (White wire). If 9-10 volts exists, go to next step. If 9-10 volts does not exist, go to step  6 .
  5. Repair open on White wire between underhood accessory wiring junction block connector C1 terminal F6 and PCM connector C2 terminal No. 8. Recheck system.
  6. Check voltage (backprobe) between ground and underhood accessory wiring junction block connector C2 terminal A6 (White wire). If 9-10 volts exists, go to next step. If 9-10 volts does not exist, go to step  8 .
  7. Replace underhood accessory wiring junction block. Recheck system.
  8. Check voltage (backprobe) between ground and instrument cluster connector C2 terminal "H" (White wire). If 9-10 volts exists, go to next step. If 9-10 volts does not exist, go to step  10 .
  9. Repair open in White wire between instrument cluster connector C2 terminal "H" and underhood accessory wiring junction block connector C2 terminal A6. Recheck system.
  10. Turn ignition off. Disconnect instrument cluster connector C2. Using test light connected to battery voltage, probe instrument cluster harness connector C2 terminal "H" (White wire). If test light illuminates, go to next step. If test light does not illuminate, go to step  12 .
  11. Repair open in White wire between instrument cluster connector C2 terminal "H" and PCM connector C2 terminal No. 8. Recheck system.
  12. Replace instrument cluster. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Recheck system operation.
  13. Replace PCM. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. Recheck system.
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