DTC U0028 [INSTRUMENT CLUSTER]

id0902e8496500

DTC U0028

Invalid data received from climate control unit (ambient temperature signal)
DETECTION CONDITION
Climate control unit malfunction or circuit malfunction
POSSIBLE CAUSE
•  Open circuit in wiring harness between instrument cluster terminal 1I and climate control unit terminal J
•  Short to power supply in wiring harness between instrument cluster terminal 1I and climate control unit terminal J
•  Short to GND in wiring harness between instrument cluster terminal 1I and climate control unit terminal J
•  Climate control unit malfunction
•  Instrument cluster malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
INSPECT CLIMATE CONTROL UNIT CONNECTOR
•  Turn the ignition switch to the LOCK position.
•  Disconnect the climate control unit connector.
•  Inspect the climate control unit connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 6.
No
Go to the next step.
2
INSPECT INSTRUMENT CLUSTER CONNECTOR
•  Disconnect the instrument cluster connector.
•  Inspect the instrument cluster connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 6.
No
Go to the next step.
3
INSPECT CLIMATE CONTROL UNIT SIGNAL CIRCUIT FOR OPEN CIRCUIT
•  Inspect for continuity between instrument cluster terminal 1I (wiring harness-side) and climate control unit terminal J (wiring harness-side)
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open circuit, then go to Step 6.
4
INSPECT CLIMATE CONTROL UNIT SIGNAL CIRCUIT FOR SHORT TO GND
•  Inspect for continuity between instrument cluster terminal 1I (wiring harness-side) and body GND.
•  Is there continuity?
Yes
Repair or replace the wiring harness for a possible short to GND, then go to Step 6.
No
Go to the next step.
5
INSPECT CLIMATE CONTROL UNIT SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
•  Turn the ignition switch to the ON position (Engine off).
•  Measure the voltage between instrument cluster terminal 1I (wiring harness-side) and body GND.
•  Is the voltage B+?
Yes
Repair or replace the wiring harness for a possible short to power supply, then go to the next step.
No
Replace the climate control unit, then go to the next step.
(See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
6
VERIFY TROUBLESHOOTING COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the instrument cluster memory using the M-MDS.
•  Turn the ignition switch to the LOCK position then the ON position.
•  Is the same DTC present?
Yes
Replace the instrument cluster.
(See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
No
Troubleshooting completed.