Diagnostic Procedure

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.

STEP	INSPECTION	ACTION
1	PERFORM DTC INSPECTION Perform meter and climate control unit DTC inspection. Verify the meter DTC inspection and indicator unit output check mode. Are DTCs and error codes output?	Yes	Perform the diagnosis according to the inspection procedure for each code.
1		No	Go to the next step.
2	DETERMINE IF THE MALFUNCTION CAUSE IS THE SEAT WARMER SWITCH Select either Low, Mid, or High on the seat warmer switch. Does the seat warmer switch LED illuminate?	Yes	Go to the next step.
2		No	Inspect the climate control unit or indicator unit. (See CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER] .) (See INDICATOR UNIT INSPECTION .)
3	DETERMINE MALFUNCTIONING SYSTEM Are the seat warmers on both sides not operating?	Yes	Go to step 9.
3		No	Go to the next step.
4	INSPECT THE SEAT WARMER CONTROL UNIT POWER SUPPLY FUSE Inspect the SEAT WARM 20 A fuse. Is the fuse normal?	Yes	Go to the next step.
4		No	If the fuse is deterioration: Replace the malfunctioning fuse. If the fuse is melt Repair the short to ground in wiring harness between the following terminals: SEAT WARM 20 A fuse- Seat warmer control unit O SEAT WARM 20 A fuse- Seat warmer control unit M
5*	DETERMINE IF CAUSE OF MALFUNCTION IS CONTROLLER POWER SUPPLY WIRING HARNESS FOR SEAT WARMER OR OTHER CAUSE Switch the ignition off (LOCK). Disconnect the seat warmer control unit connector. Measure the voltage at the following terminal (wiring harness-side): Seat warmer control unit terminal M Seat warmer control unit terminal O Is the voltage B+ ?	Yes	Go to the next step.
5*		No	Repair or replace the open circuit at the following wiring harness. SEAT WARMER 20 A fuse-Seat warmer control unit
6*	VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN SEAT WARMER CONTROL UNIT POWER SUPPLY WIRING HARNESS Seat warmer control unit connector are disconnected. Switch the ignition off (LOCK). Measure the voltage at the following terminal (wiring harness-side): Seat warmer control unit terminal K Is the voltage B+ ?	Yes	Go to the next step.
6*		No	Inspect the front body control module (FBCM) 1C terminal. (See FRONT BODY CONTROL MODULE (FBCM) INSPECTION .) Repair or replace the open circuit at the following wiring harness. Front body control module (FBCM) terminal 1C-Seat warmer control unit terminal K
7*	VERIFY IF MALFUNCTION CAUSE IS SHORT TO GROUND IN SEAT WARMER CONTROL UNIT Seat warmer control unit connector on the side that is not operating is disconnected. Inspect for continuity between the following terminals (wiring harness-side): Seat warmer control unit terminal on the side that is not operating H-Ground Seat warmer control unit terminal on the side that is not operating G-Ground Is there continuity?	Yes	Go to the next step.
7*		No	Inspect the open circuit following. Seat warmer unit terminal H-GND Seat warmer unit terminal G-GND Inspect the GND connector terminals for poor connection. Repair or replace the malfunction.
8*	VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF SEAT WARMER SWITCH SIGNAL Seat warmer control unit connector is disconnected. Inspect for continuity between the following terminals (wiring harness-side): With full-auto air conditioner Seat warmer control unit terminal I-Climate control terminal 1E With manual air conditioner Seat warmer control unit terminal I-Indicator unit terminal D Is there continuity?	Yes	Go to the next step.
8*		No	Inspect the open circuit following. Seat warmer control unit terminal I-Climate control terminal 1E Seat warmer control unit terminal I-Indicator unit terminal D
9*	INSPECT SEAT WARMER CONTROL UNIT AND SEAT WARMER UNIT CONNECTOR Disconnect the seat warmer control unit and seat warmer unit connector on the side not operating. Inspect the seat warmer control unit and seat warmer unit connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion). Is there any malfunction?	Yes	Repair or replace the malfunctions.
9*		No	Go to the next step.
10*	VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF SEAT WARMER UNIT CIRCUIT Switch the ignition off (LOCK). Disconnect the seat warmer control unit connector. Inspect for continuity between the following terminals (wiring harness-side): Driver-side seat warmer unit terminal P-A Passenger-side seat warmer unit terminal N-B Is there continuity?	Yes	Go to the next step.
10*		No	Replace the seat warmer unit.
11	DETERMINE IF THE MALFUNCTION CAUSE IS SEAT WARMER CONTROL UNIT With full-auto air conditioner Replace the climate control unit. With manual air conditioner Replace the indicator unit. Does the seat warmer system operate?	Yes	Troubleshooting completed.
11		No	Replace the seat warmer control unit.