Pinpoint Test F: The Tachometer Is Inoperative

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test F: The Tachometer Is Inoperative

Normal Operation

The Instrument Cluster (IC) receives the tachometer data from the PCM over the communication network and commands the tachometer pointer between 0 and 7,000 rpm (4.0L and 5.4L engines), or between 0 and 8,000 rpm (4.6L engine) according to the data.

This pinpoint test is intended to diagnose the following:

- PCM
- IC



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 DTCs recorded?

Yes
REFER to Computers and Control Systems Information.

No
GO to F2.

-------------------------------------------------
F2 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_IND) active command and scroll in increments of 10% while monitoring the tachometer. The tachometer should increase in increments of approximately 700 rpm (4.0L engine), or 800 rpm (4.6L engine) for each 10% change.
- Does the tachometer gauge increase within specifications?

Yes
INSTALL a new PCM. TEST the system for normal operation.

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

-------------------------------------------------