DTC Troubleshooting: C1C21-12

DTC C1C21-12: Back-Up Light Switch Stuck ON

NOTE:

	Before you troubleshoot, review the general troubleshooting information.
	If DTC U0029-00 is indicated at the same time, do the DTC U0029-00 troubleshooting first.

DTC Description	DTC	Freeze Frame
C1C21-12 Back-Up Light Switch Stuck ON

Back-up lights check:

Back-up lights check

?1.	Turn the vehicle to the ON mode.

?2.	Check the back-up lights when the shift lever is in neutral.

Are the back-up lights off?


	YES

Go to step 5.


	NO

Go to step 2.

Back-up light switch check 1:

Back-up light switch check 1

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.

Disconnect the following connector.

Back-up light switch 2P connector

?3.	Turn the vehicle to the ON mode.

?4.	Shift the shift lever into neutral.

Are the back-up lights off?


	YES

Go to step 4.


	NO

Go to step 3.

MICU check:

MICU check

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.

Disconnect the following connector.

Under-dash fuse/relay box connector Q (40P)

?3.	Turn the vehicle to the ON mode.

?4.	Shift the shift lever into neutral.

Are the back-up lights off?


	YES

Repair a short to power in the wire between the back-up light switch and the under-dash fuse/relay box.?


	NO

Replace the MICU.?

Back-up light switch check 2:

Back-up light switch check 2

?1.	Check the back-up light switch.

Is the back-up light switch OK?


	YES

Check the reverse shift mechanism in the transmission.?


	NO

Replace the back-up light switch.?

Back-up light switch performance check:

Back-up light switch performance check

?1.

Check the parameter(s) below with the HDS.

Signal	Current conditions
Signal	Values	Unit
BACK-UP LIGHT SWITCH

Does it indicate ON when the shift lever is in reverse, and OFF when the shift lever is in neutral?


	YES

Go to step 7.


	NO

Go to step 6.

Body electrical system DTC check:

Body electrical system DTC check

?1.

Check for gauge control module DTCs with the HDS.

DTC Description	DTC

Are any DTCs indicated?


	YES

Go to indicated DTC's troubleshooting.?


	NO

Replace the MICU.?

VSA modulator-control unit check:

VSA modulator-control unit check

?1.	Clear the DTC with the HDS.

?2.	Turn the vehicle to the OFF (LOCK) mode.

?3.	Test-drive the vehicle. NOTE: Drive the vehicle on the road, not on a lift.

?4.

Check for DTCs with the HDS.

DTC Description	DTC	Freeze Frame
C1C21-12 Back-Up Light Switch Stuck ON

Is DTC C1C21-12 indicated?


	YES

Go to step 8.


	NO

Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the Freeze data/on-board snapshot.?

VSA modulator-control unit check (update):

VSA modulator-control unit check (update)

?1.	Update the VSA modulator-control unit if it does not have the latest software.

?2.	Turn the vehicle to the OFF (LOCK) mode.

?3.	Test-drive the vehicle. NOTE: Drive the vehicle on the road, not on a lift.

?4.

Check for DTCs with the HDS.

DTC Description	DTC	Freeze Frame

Is DTC C1C21-12 indicated?


	YES

Check for loose terminals and poor connections in the VSA modulator-control unit 38P connector. If the VSA modulator-control unit was updated and the symptom/indication is still present, replace the VSA modulator-control unit.?


	NO

Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTCs troubleshooting.?