Pinpoint Test E: The Temperature Gauge Is Inoperative

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test E: The Temperature Gauge Is Inoperative

Normal Operation

The PCM uses the Engine Coolant Temperature (ECT) sensor to measure the engine coolant temperature on the 6.7L diesel engine and the Cylinder Head Temperature (CHT) sensor on the 6.2L and 6.8L gasoline engines. The Instrument Panel Cluster (IPC) receives the engine coolant temperature data from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The IPC monitors the engine coolant temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

If the IPC receives invalid engine coolant temperature data from the PCM for 5 seconds or less, the IPC defaults the temperature gauge to the last setting, based upon the last known good temperature status message. If the IPC does not receive the engine coolant temperature status message from the PCM or if the data received is deemed invalid for more than 5 seconds, the IPC sets DTC U0100:00 in continuous memory and defaults the temperature gauge to cold (C). If the engine coolant temperature data is deemed invalid by the IPC, the IPC sets DTC U0401:00 and defaults the temperature gauge to cold (C).

NOTE: If DTC U0100:00 sets in the IPC, other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM
- IPC

PINPOINT TEST E: THE TEMPERATURE GAUGE IS INOPERATIVE

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

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

Yes
REFER to Computers and Control Systems. TEST the system for normal operation.

No
GO to E2.

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E2 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST

- Check for recorded IPC DTCs from the self-test.
- Are any DTCs recorded?

Yes
For DTC U0100:00, GO to Pinpoint Test BA Pinpoint Tests BA: DTC U0100:00. For all other DTCs, REFER to DTC Charts.

No
GO to E3.

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E3 CARRY OUT THE TEMPERATURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC DataLogger.

- NOTE: Make sure the scan tool is set to 0 or full cold before beginning this step.

- Select the IPC temperature gauge (ENGCOOLNT) active command. Command the temperature gauge on and off while monitoring the gauge.
- Does the temperature gauge start at cold (C), move to full hot (H) and return to cold (C)?

Yes
INSTALL a new PCM. REFER to Electronic Engine Controls Powertrain Control Module (PCM). TEST the system for normal operation.

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

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