Pinpoint Test D: Incorrect Temperature Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test D: Incorrect Temperature Gauge Indication
Normal Operation
The PCM uses the Cylinder Head Temperature (CHT) sensor to measure the engine coolant temperature. 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 engine coolant temperature data is missing or invalid for 5 seconds or less or if the IPC receives invalid engine coolant temperature data for 5 seconds or less, the IPC defaults the temperature gauge to the last setting, based upon the last known good temperature status message received.
If the IPC does not receive the engine coolant temperature status message from the PCM 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 for 5 seconds or more, the IPC sets DTC U0401:86 and defaults the temperature gauge to cold (C).
NOTE: If DTC U0100:00 is set in the IPC, other observable symptoms may be an inoperative tachometer, speedometer or odometer.
This pinpoint test is intended to diagnose the following:
- PCM concern
- IPC
PINPOINT TEST D: INCORRECT TEMPERATURE GAUGE INDICATION
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D1 CHECK FOR CORRECT OPERATION OF THE COOLING SYSTEM
- Verify that the engine cooling system and thermostat are functioning correctly.
- Does the engine cooling system and thermostat operate correctly?
Yes
GO to D2.
No
REFER to Engine Cooling Component Tests and General Diagnostics.
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D2 RETRIEVE THE RECORDED DTCs FROM THE KOEO PCM SELF-TEST
- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any DTCs recorded?
Yes
DIAGNOSE all PCM DTCs first. REFER to Computers and Control Systems.
No
GO to D3.
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D3 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST
- Check for recorded DTCs from the IPC self-test.
- Are any DTCs recorded?
Yes
For DTC U0100:00, GO to Pinpoint Test AU. Pinpoint Tests AU: DTC U0100:00
For all other DTCs, REFER to DTC Charts.
No
GO to D4.
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D4 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: 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 123°C (253°F) with the gauge in the hot (H) range.
- 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 D5.
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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D5 CHECK THE COOLANT TEMPERATURE INPUT USING THE DEALER TEST MODE
- Ignition ON.
- Enter the IPC dealer test mode.
- NOTE: The display below uses xxx's to represent a numeric or alpha-numeric value. The value may display the same amount of characters represented by the xxx's or there may be more/less depending on the type of display and that the minus symbol in parenthesis will only appear if the temperature is below 0°C. For example: COOLANT TEMP xxx C may display COOLANT TEMP 20 C. Note that there were 3 x's in the display description but only 2 digits in the actual display.
- Scroll through the displays to ECt xxx °C (base IPC) or COOLANT TEMP xxx C (message center IPC).
- Start the engine and run the engine through a variety of engine temperatures.
- NOTE: 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 123°C (253°F) with the gauge in the hot (H) range.
- Monitor the engine coolant temperature input to the IPC and the coolant temperature gauge indication.
- Does the engine coolant input agree with the position of the temperature gauge indication?
Yes
The temperature gauge is operating correctly at this time.
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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