Pinpoint Test E: The Tachometer Is Inoperative

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test E: The Tachometer Is Inoperative

Normal Operation

The PCM uses the Crankshaft Position (CKP) sensor to measure the engine rpm. The PCM sends the Instrument Cluster (IC) the engine rpm data over the communication network to command the tachometer according to the data.

This pinpoint test is intended to diagnose the following:

- PCM concern
- IC



PINPOINT TEST E: THE TACHOMETER IS INOPERATIVE

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E1 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST


- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any DTCs recorded?

Yes
REFER to Computers and Control Systems Information to continue diagnosis of the DTCs.

No
GO to E2.

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E2 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


- Check for recorded continuous memory IC DTCs.
- Is DTC U1900 recorded?

Yes
REFER to Information Bus to diagnose communication with the PCM.

No
GO to E3.

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E3 CARRY OUT THE IC TACHOMETER ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC tachometer (TACH) active command. Command the tachometer on. Observe the tachometer.
- Does the tachometer begin at 0 rpm and move to 7000 rpm when commanded on?

Yes
GO to E4.

No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.

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E4 CHECK THE PCM RPM PID


- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Select the PCM engine rpm PID (RPM) and monitor the PID while the engine is running.
- Start the engine.
- Does the PID agree with the position of the tachometer gauge?

Yes
The system is operating correctly at this time.

No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.

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