Pinpoint Test C: The Temperature Gauge Is Inoperative
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
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 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 receives invalid engine temperature data for 5 seconds or less, the IC defaults the temperature gauge to the last setting, based upon the last known good temperature status message. If the IC does not receive the engine temperature status message from the PCM for more than 5 seconds, the IC) 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 for 5 seconds or more, the IC sets DTC U2023 and defaults the temperature gauge to cold (C).
NOTE: If DTC U0100 is set in the IC, other observable symptoms may be an inoperative tachometer, speedometer or odometer.
This pinpoint test is intended to diagnose the following:
- PCM
- IC
PINPOINT TEST C: THE TEMPERATURE GAUGE IS INOPERATIVE
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C1 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 PCM DTCs recorded?
Yes
DIAGNOSE all PCM DTCs first. REFER to Computers and Control Systems.
No
GO to C2.
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C2 CARRY OUT THE TEMPERATURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC 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:
- Does the temperature gauge operate according to the above specifications?
Yes
GO to C3.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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C3 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Check for recorded IC 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 Computers and Control Systems and Multifunction Electronic Modules Testing and Inspection 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. REFER to Electronic Engine Controls Service and Repair. TEST the system for normal operation.
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