NO.3 TEMPERATURE FOR HEATED STEERING WHEEL SYSTEM CANNOT BE STABLE [HEATED STEERING WHEEL]

id0603a3951300

Description
•  Heated steering wheel temperature is low
•  Heated steering wheel temperature continues to rise
Possible Causes
Heated steering wheel control unit cannot control heated steering wheel unit
•  Heated steering wheel control unit malfunction
•  Thermostat (built into heated steering wheel unit) malfunction
•  Thermistor (built into heated steering wheel unit) malfunction
•  When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while performing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions.
If there is a problem, check to make sure connectors, terminals and wiring harnesses are connected correctly and undamaged.

Diagnostic Procedure

STEP

INSPECTION

ACTION
1*
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF HEATED STEERING WHEEL UNIT CIRCUIT
Warning
•  Handling the component parts improperly can accidentally operate (deploy) the air bag module, which may seriously injure you. Read the service warnings/cautions and the workshop manual before handling the air bag system components.
•  Switch the ignition to off (LOCK).
•  Disconnect the negative battery terminal and wait for 1 min or more.
•  Remove the driver-side air bag module connector.
•  Disconnect the heated steering wheel unit connector.
•  Inspect for continuity between the following terminals (wiring harness-side):
?  Heated steering wheel unit terminal A—B
?  Heated steering wheel unit terminal C—D
•  Is there continuity?
Yes
Replace the heated steering wheel control unit, then go to the next step.
(See HEATED STEERING WHEEL CONTROL UNIT REMOVAL/INSTALLATION.)
No
Replace the steering wheel, then go to the next step.
(See STEERING WHEEL AND COLUMN REMOVAL/INSTALLATION.)
2
VERIFY IF MALFUNCTION CAUSE IS CORRECTED
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Operate the heated steering wheel switch to turn on the heated steering wheel system.
•  Does the heated steering wheel system operate normally?
Yes
Troubleshooting completed. (Explain the contents of the servicing to the customer.)
No
Verify the malfunction symptom in the symptom troubleshooting chart and perform the other applicable malfunction diagnosis.
(See SYMPTOM TROUBLESHOOTING [HEATED STEERING WHEEL].)