Pinpoint Test C: The Temperature Gauge Is Inoperative

Instrumentation, Message Center and Warning Chimes

Pinpoint Test C: The Temperature Gauge Is Inoperative

Normal Operation

The PCM uses the Cylinder Head Temperature (CHT) sensor to measure the engine temperature. The Instrument Cluster (IC) receives the engine temperature data from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The IC (Instrument Cluster) monitors the engine temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

If the engine temperature data is missing for 5 seconds or less or if the IC (Instrument Cluster) receives invalid engine temperature data for 5 seconds or less, the IC (Instrument Cluster) defaults the temperature gauge to the last setting, based upon the last known good temperature status message. If the IC (Instrument Cluster) does not receive the engine temperature status message from the PCM for more than 5 seconds, the IC (Instrument Cluster)) sets DTC U0100 in continuous memory and defaults the temperature gauge to cold (C). If the engine coolant temperature data is deemed invalid by the IC (Instrument Cluster) for 5 seconds or more, the IC (Instrument Cluster) sets DTC U2023 and defaults the temperature gauge to cold (C).

NOTE: If DTC U0100 is set in the IC (Instrument Cluster), other observable symptoms may be an inoperative tachometer, speedometer or odometer.

This pinpoint test is intended to diagnose the following:

- PCM

- IC (Instrument Cluster)

PINPOINT TEST C : THE TEMPERATURE GAUGE IS INOPERATIVE

C1 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO (Key ON Engine OFF) SELF-TEST

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

Are any PCM DTCs recorded?

Yes
DIAGNOSE all PCM DTCs first. REFER to the Computers and Control Systems Information.

No
GO to C2.

C2 CARRY OUT THE TEMPERATURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: IC (Instrument Cluster) DataLogger.

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

Select the instrument temperature gauge (ENGCOOLNT) active command. Command the temperature gauge according to the following table:

Temperature Command Gauge Position Below 50°C (122°F) Cold (C) Approximately 87°C (189°F) Just left of center (mid-range) Above 121°C (250°F) Full hot (H)

Does the temperature gauge operate according to the above specifications?

Yes
GO to C3.

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

C3 RETRIEVE THE RECORDED DTCs FROM THE IC (Instrument Cluster) SELF-TEST

- Check for recorded IC (Instrument Cluster) DTCs from the self-test.

Are any DTCs recorded?

Yes
For DTC U0100, GO to Pinpoint Test AO. Pinpoint Test AO: DTC U0100

For DTC U2023, RETRIEVE and REPAIR all non-network DTCs in the PCM and other modules on the network. REFER to the Computers and Control Systems Information and Body Control Systems for a list of all DTCs.

For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes

No
INSTALL a new PCM. TEST the system for normal operation.