DTC C1126:13 [BCM]

id0902f5940200

DESCRIPTION

Light switch (TNS) circuit malfunction
DETECTION CONDITION
•  Open circuit in the light switch (TNS) circuit with the light switch at TNS position.
POSSIBLE CAUSE
•  Light switch connector or terminals malfunction
•  Open circuit in wiring harness between the following:
―  Light switch left side:
•  Light switch terminal E—Body ground
―  Light switch right side:
•  Light switch terminal G—Body ground
•  Light switch malfunction
•  BCM connector or terminals malfunction
•  Open circuit in wiring harness between the following terminals:
―  Light switch left side:
•  Light switch terminal A—BCM terminal 2V
―  Light switch right side:
•  Light switch terminal K—BCM terminal 2V
•  BCM malfunction

Diagnostic Procedure

STEP

INSPECTION

ACTION
1
CONFIRM BCM DTC
•  Clear the DTC using the M-MDS.
•  Perform the BCM DTC inspection using the M-MDS with the light switch at TNS position.
•  Is the same DTC present?
Yes
Go to the next step.
No
Go to Step 9.
2
INSPECT LIGHT SWITCH CONNECTOR AND TERMINALS
•  Switch the ignition to off.
•  Disconnect the negative battery cable.
•  Disconnect the light switch connector.
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 8.
No
Go to the next step.
3
VERIFY MALFUNCTIONING LOCATION
•  Verify that the light switch connector is disconnected.
•  Reconnect the negative battery cable.
•  Switch the ignition to ON.
•  Measure the voltage at the following terminal (wiring harness-side):
―  Light switch left side:
•  Light switch terminal A
―  Light switch right side:
•  Light switch terminal K
•  Is there any voltage?
Yes
Go to the next step.
No
Go to Step 6.
4
INSPECT LIGHT SWITCH (TNS) GROUND CIRCUIT FOR OPEN CIRCUIT
•  Verify that the light switch connector is disconnected.
•  Switch the ignition to off.
•  Disconnect the negative battery cable.
•  Inspect for continuity between the following terminal (wiring harness-side) and body ground:
―  Light switch left side:
•  Light switch terminal E
―  Light switch right side:
•  Light switch terminal G
•  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 8.
5
INSPECT LIGHT SWITCH
•  Inspect the light switch.
•  Is there any malfunction?
Yes
Replace the light switch, then go to Step 8.
(See LIGHT SWITCH REMOVAL/INSTALLATION.)
No
Go to Step 8.
6
INSPECT BCM CONNECTOR AND TERMINALS
•  Switch the ignition to off.
•  Disconnect the negative battery cable.
•  Disconnect the BCM connector.
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 8.
No
Go to the next step.
7
INSPECT LIGHT SWITCH (TNS) CIRCUIT FOR OPEN CIRCUIT
•  Verify that the light switch and BCM connectors are disconnected.
•  Reconnect the BCM connector.
•  Reconnect the negative battery cable.
•  Measure the voltage at the BCM terminal 2V (wiring harness-side).
•  Is there any voltage?
Yes
Repair or replace the wiring harness for a possible open circuit, then go to the next step.
No
BCM internal malfunction can be considered the cause.
•  Go to the next step.
8
VERIFY TROUBLESHOOTING COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Reconnect the negative battery cable.
•  Clear the DTC using the M-MDS.
•  Perform the BCM DTC inspection using the M-MDS with the light switch at TNS position.
•  Is the same DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the BCM.
Go to the next step.
No
Go to the next step.
9
VERIFY THAT NO OTHER DTCs ARE PRESENT
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [BCM].)
No
DTC troubleshooting completed.