NO.1 HEATED STEERING WHEEL SYSTEM DOES NOT OPERATE [HEATED STEERING WHEEL]

id0603a3951100

Description
Heated steering wheel does not warm steering wheel even though heated steering wheel switch is on
Possible Causes
The power supply is not supplied to filament of heated steering wheel
•  Open circuit in heated steering wheel control unit power supply circuit:
?  Heated steering wheel control unit terminal D and battery positive terminal
•  ST.HEATER 15 A fuse malfunction (Blown fuse):
?  Short to ground in wiring harness between ST.HEATER 15 A fuse and heated steering wheel control unit terminal D
•  C/U IG1 15 A fuse malfunction (Blown fuse):
?  Short to ground in wiring harness between C/U IG1 15 A fuse and heated steering wheel relay
•  IG1 relay and Heated steering wheel relay malfunction:
?  Short to ground in wiring harness between IG1 relay and heated steering wheel relay
?  Short to ground in wiring harness between heated steering wheel relay and heated steering wheel control unit terminal D
•  Clock spring malfunction:
?  Open circuit in wiring harness between clock spring connector 6A and 7A
•  Poor connect the connector:
?  Clock spring connector and heated steering wheel control unit connector
Heated steering wheel control unit not operation
•  Open circuit in wiring harness between the following terminal:
?  Heated steering wheel control unit terminal A and body ground
•  Clock spring malfunction:
?  Open circuit in wiring harness between clock spring connector 6B and 7B
Heated steering wheel unit cannot control filament on
•  Heated steering wheel unit malfunction
Heated steering wheel filament does not generate heat
•  Heated steering wheel unit malfunction
Heated steering wheel control unit cannot receive operation signal
•  Heated steering wheel control unit malfunction
•  Open circuit or short to ground in wiring harness between the following terminal:
?  Heated steering wheel control unit terminal C and indicator unit terminal I
•  Clock spring malfunction:
?  Open circuit in wiring harness between clock spring connector 6D and 7D
•  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
DETERMINE IF MALFUNCTION CAUSE IS HEATED STEERING WHEEL SWITCH
•  Operate the heated steering wheel switch to turn on the heated steering wheel system.
•  Does the heated steering wheel switch LED illuminate?
Yes
Go to the next step.
No
Inspect the indicator unit, then go to step 14.
(See INDICATOR UNIT INSPECTION.)
2
INSPECT IG1 RELAY
•  Inspect the IG1 relay.
•  Is the relay normal?
Yes
Go to the next step.
No
Inspect the IG1 relay, then go to step 14.
(See RELAY INSPECTION.)
3
INSPECT HEATED STEERING WHEEL CONTROL UNIT POWER SUPPLY FUSE
•  Inspect the C/U IG1 15 A fuse.
•  Is the fuse normal?
Yes
Go to the next step.
No
•  If the fuse is deterioration:
?  Replace the malfunctioning fuse.
•  If the fuse is blown:
Repair the short to ground in wiring harness between the following terminals:
?  C/U IG1 15 A fuse and heated steering wheel relay terminal A
•  Go to step 14.
4
INSPECT HEATED STEERING WHEEL CONTROL UNIT POWER SUPPLY FUSE
•  Inspect the ST.HEATER 15 A fuse.
•  Is the fuse normal?
Yes
Go to the next step.
No
•  If the fuse is deterioration:
?  Replace the malfunctioning fuse.
•  If the fuse is blown:
Repair the short to ground in wiring harness between the following terminals:
?  ST.HEATER 15 A fuse and heated steering wheel relay terminal D
•  Go to step 14.
5
INSPECT HEATED STEERING WHEEL RELAY
•  Inspect the heated steering wheel relay.
•  Is the relay normal?
Yes
Go to the next step.
No
Inspect the heated steering wheel relay, then go to step 14.
(See RELAY INSPECTION.)
6*
VERIFY IF MALFUNCTION CAUSE IS HEATED STEERING WHEEL CONTROL UNIT POWER SUPPLY 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 off (LOCK).
•  Disconnect the negative battery terminal and wait for 1 min or more. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.)
•  Remove the driver-side air bag module connector.
•  Remove the steering wheel.
•  Remove the column cover.
•  Remove the clock spring.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following terminals (vehicle wiring harness side).
?  Clock spring connector 3 terminal 6A
•  Is the voltage B+?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminal.
?  Heated steering wheel relay terminal C and clock spring connector 3 terminal 6A
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which is shorted to ground.
•  Replace the fuse.
Go to Step 14.
7*
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN CLOCK SPRING CONNECTOR AND BODY GROUND
•  Switch the ignition OFF (LOCK).
•  Verify that the clock spring connector 3 is disconnected.
•  Inspect for continuity between the following terminals (vehicle wiring harness side) and body ground.
?  Clock spring connector 3 terminal 6D
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between the following terminals and body ground.
?  Clock spring connector 3 terminal 6D
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 14.
8*
VERIFY IF MALFUNCTION CAUSE IS SHORT CIRCUIT TO GROUND IN WIRING HARNESS BETWEEN CLOCK SPRING CONNECTOR AND INDICATOR UNIT
•  Verify that the clock spring connector 3 is disconnected.
•  Disconnect the indicator unit connector.
•  Inspect for continuity between clock spring connector 3 terminal 6B (vehicle wiring harness side) and body ground.
•  Is there continuity?
Yes
•  Refer to the wiring diagram and verify if there is a common connector between clock spring connector 3 terminal 6B and indicator unit terminal I.
If there is a common connector:
?  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
?  Repair or replace the malfunctioning location.
If there is no common connector:
?  Repair or replace the wiring harness which is shorted to ground.
•  Go to Step 14.
No
Go to the next step.
9*
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN CLOCK SPRING CONNECTOR AND INDICATOR UNIT
•  Verify that the clock spring connector 3 and the indicator unit connector are disconnected.
•  Inspect the wiring harness for continuity between clock spring connector 3 terminal 6B and indicator unit terminal I (vehicle wiring harness side).
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between clock spring connector 3 terminal 6B and indicator unit terminal I.
If there is a common connector:
?  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
?  Repair or replace the malfunctioning location.
If there is no common connector:
?  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 14.
10*
DETERMINE IF CAUSE OF MALFUNCTION IS CLOCK SPRING
•  Inspect for continuity between the following terminals:
?  Clock spring connector 3 terminal 6A and 7A
?  Clock spring connector 3 terminal 6B and 7B
?  Clock spring connector 3 terminal 6D and 7D
•  Is there continuity?
Yes
Go to the next step.
No
•  Inspect the clock spring, then go to step 14.
11*
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN CLOCK SPRING AND HEATED STEERING WHEEL CONTROL UNIT
•  Verify that the heated steering wheel control unit connector (clock spring side) is disconnected.
•  Disconnect the is heated steering wheel control unit connector (unit side).
•  Inspect for continuity between the following terminals.
?  Heated steering wheel control unit harness connector terminal 7A and D
?  Heated steering wheel control unit harness connector terminal 7B and C
?  Heated steering wheel control unit harness connector terminal 7D and A
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness which has an open circuit, then go to step 14.
12*
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF HEATED STEERING WHEEL UNIT CIRCUIT
•  Inspect for continuity between the following terminals (wiring harness-side);
?  Heated steering wheel unit terminal A and B
?  Heated steering wheel unit terminal C and D
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness which has an open circuit, then go to the next step.
(See STEERING WHEEL AND COLUMN REMOVAL/INSTALLATION.)
13
DETERMINE IF MALFUNCTION CAUSE IS HEATED STEERING WHEEL CONTROL UNIT
•  Reconnect all the disconnected connectors.
•  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 seat warmer system operate normally?
Yes
Go to the next step.
No
Replace the heated steering wheel control unit, then go to the next step.
(See HEATED STEERING WHEEL CONTROL UNIT REMOVAL/INSTALLATION.)
14
VERIFY IF MALFUNCTION CAUSE IS CORRECTED
•  Operate the heated steering wheel switch to turn on the heated steering wheel system.
•  Does the seat warmer 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].)