Diagnostic Procedure

WARNING: This page is about a different car, the 2010 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

DTC C0040:29 (ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM) DIAGNOSTIC PROCEDURE

Step	Inspection		Action
1	INSPECT BRAKE SWITCH CONNECTOR AND TERMINALS Switch the ignition to off. Disconnect the negative battery cable. Disconnect the brake 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.
1		No	Go to the next step.
2	INSPECT BRAKE SWITCH CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND Brake switch connector is disconnected. Reconnect the negative battery cable. Switch the ignition to ON. Measure the voltage at the following terminal (wiring harness-side): Brake switch terminal A Is the voltage B+ ?	Yes	Go to the next step.
2		No	Inspect the STOP 15 A fuse. If the fuse is melt: Repair or replace the wiring harness for a possible short to ground. Replace the fuse. If the fuse is deterioration: Replace the fuse. If the fuse is normal: Repair or replace the wiring harness for a possible open circuit. Go to Step 8.
3	INSPECT BRAKE SWITCH GROUND CIRCUIT FOR OPEN CIRCUIT Brake 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: Brake switch terminal B Is there continuity?	Yes	Go to the next step.
3		No	Repair or replace the wiring harness for a possible open circuit, then go to Step 8.
4	INSPECT KEYLESS CONTROL MODULE CONNECTOR AND TERMINALS Disconnect the keyless control module 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.
4		No	Go to the next step.
5	INSPECT BRAKE SWITCH CIRCUIT FOR SHORT TO GROUND Brake switch and keyless control module connectors are disconnected. Inspect for continuity between the following terminals (wiring harness-side) and body ground: Brake switch terminal C Brake switch terminal D Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to ground, then go to Step 8.
5		No	Go to the next step.
6	INSPECT BRAKE SWITCH CIRCUIT FOR SHORT TO POWER SUPPLY Brake switch and keyless control module connectors are disconnected. Reconnect the negative battery cable. Switch the ignition to ON. Measure the voltage at the following terminal (wiring harness-side): Brake switch terminal D Is there any voltage?	Yes	Repair or replace the wiring harness for a possible short to power supply, then go to Step 8.
6		No	Go to the next step.
7	INSPECT BRAKE SWITCH CIRCUIT FOR OPEN CIRCUIT Brake switch and keyless control module connectors are disconnected. Switch the ignition to off. Disconnect the negative battery cable. Inspect for continuity between the following terminals (wiring harness-side): Brake switch terminal C-Keyless control module terminal 4W Brake switch terminal D-Keyless control module terminal 3R Is there continuity?	Yes	Replace the brake switch, then go to the next step. (See BRAKE PEDAL REMOVAL/INSTALLATION .)
7		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
8	VERIFY TROUBLESHOOTING COMPLETED Make sure to reconnect the disconnected connectors. Reconnect the negative battery cable. Operate the advanced key to activate the keyless control module. Clear the DTC from the keyless control module using the M-MDS. (See CLEARING DTC [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] .) Operate the advanced key to activate the keyless control module. Perform the advanced keyless entry and push button start system DTC inspection using the M-MDS. (See DTC INSPECTION [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] .) Is the same DTC present?	Yes	Replace the keyless control module, then go to the next step. (See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION .)
8		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 [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] .)
9		No	DTC troubleshooting completed.