Pinpoint Test F: Incorrect Temperature Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Test F: Incorrect Temperature Gauge Indication
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 (Instrument Panel Cluster) 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 (Instrument Panel Cluster) receives invalid engine coolant temperature data from the PCM for 5 seconds or less, the IPC (Instrument Panel Cluster) defaults the temperature gauge to the last setting, based upon the last known good temperature status message. If the IPC (Instrument Panel Cluster) 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 (Instrument Panel Cluster) 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 (Instrument Panel Cluster), the IPC (Instrument Panel Cluster) sets DTC U0401:00 and defaults the temperature gauge to cold (C).
NOTE: If DTC U0100:00 sets in the IPC (Instrument Panel Cluster), other observable symptoms may be an inoperative speedometer, tachometer or odometer.
This pinpoint test is intended to diagnose the following:
- PCM concern
- IPC (Instrument Panel Cluster)
PINPOINT TEST F : INCORRECT TEMPERATURE GAUGE INDICATION
F1 CHECK FOR CORRECT OPERATION OF THE COOLING SYSTEM
- Verify the engine cooling system and thermostat are functioning correctly.
Do the engine cooling system and thermostat operate correctly?
Yes
GO to F2.
No
REFER to Cooling System &/or Engine Block Heater (gasoline engine) or Cooling System (diesel engine).
F2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO (Key ON Engine OFF) SELF-TEST
- Check the recorded PCM DTCs from the KOEO (Key ON Engine OFF) self-test.
Are any DTCs recorded?
Yes
REFER to Computers and Control Systems Information. TEST the system for normal operation.
No
GO to F3.
F3 RETRIEVE THE RECORDED DTCs FROM THE IPC (Instrument Panel Cluster) SELF-TEST
- Check for recorded IPC (Instrument Panel Cluster) DTCs from the self-test.
Are any DTCs recorded?
Yes
For DTC U0100:00, GO to Pinpoint Test BA. Pinpoint Test BA: DTC U0100:00
For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes
No
GO to F4.
F4 CARRY OUT THE TEMPERATURE GAUGE ACTIVE COMMAND USING THE SCAN TOOL
NOTE: On gasoline engines, the coolant temperature should range between 0-59°C (32-138°F) with the gauge in the cold (C) range, between 60-120°C (140-248°F) with the gauge in the normal or mid-range and above 121°C (250°F) with the gauge in the hot (H) range.
NOTE: On diesel engines, the coolant temperature should range between 0-59°C (32-138°F) with the gauge in the cold (C) range, between 60-115°C (140-239°F) with the gauge in the normal or mid-range and above 116°C (241°F) with the gauge in the hot (H) range.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC (Instrument Panel Cluster) DataLogger.
- NOTE: Make sure the scan tool is set to 0 or full cold before beginning this step.
Select the IPC (Instrument Panel Cluster) temperature gauge (ENGCOOLNT) active command. Command the temperature gauge according to the following table:
Temperature Command Gauge Position 20% Beginning of the normal band 50% Center of the gauge (mid-range) 90% End of the normal band
Does the temperature gauge operate according to the above specifications?
Yes
GO to F5.
No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.
F5 CHECK THE PCM TEMPERATURE PID
NOTE: On gasoline engines, the coolant temperature should range between 0-59°C (32-138°F) with the gauge in the cold (C) range, between 60-120°C (140-248°F) with the gauge in the normal or mid-range and above 121°C (250°F) with the gauge in the hot (H) range.
NOTE: On diesel engines, the coolant temperature should range between 0-59°C (32-138°F) with the gauge in the cold (C) range, between 60-115°C (140-239°F) with the gauge in the normal or mid-range and above 116°C (241°F) with the gauge in the hot (H) range.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Ignition ON.
- Select the PCM temperature PID (CHT) (gasoline) or (ECT1) (diesel). With the engine running, monitor the PCM temperature PID.
Does the PCM PID agree with the position of the temperature gauge indication?
Yes
The temperature gauge is operating correctly at this time.
No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.