1. Measure the voltage at the door lock timer unit terminals (other than terminal 1E and 2W) as indicated below.
2. Disconnect the negative battery cable.
3. Disconnect the door lock timer unit connector and inspect for continuity between terminal 1E or 2W and the bracket.
4. Inspect for continuity at terminal 1E and 2W as indicated below.
5. If the parts and wiring harnesses are okay but the system still does not work properly, perform the troubleshooting.
Terminal voltage list (Reference)



*1 : Vehicles with double locking system
*2 : Vehicles with theft-deterrent system
Door lock timer unit removal/installation
Door lock timer unit id code changeMazda 6 Service Manual: Front buckle removal/installation
1. Perform the following procedure for vehicles with seat belt warning.
(1) Disconnect the negative battery cable.
(2) Remove the front seat.
(3) Disconnect the buckle switch connector.
2. Perform the following procedure for vehicles without seat belt warning.
(1) Remove the console.
...
Mazda 6 Service Manual: Instrument cluster repair
Note
The needle of speedometer or tachometer may continue to rotate
clockwise until it indicates over maximum graduation. If a customer
complains of this concern, repair the needle position according to the
following steps.
1. Verify the concern.
2. Turn the ignition switch to LOC ...