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Home >> Mazda >> 2011 >> 3 Mazdaspeed, 2.3 3 >> Repair and Diagnosis >> Body & Frame >> Door Locks >> On-Board Diagnostic [Advanced Keyless Entry And Push Button Start System] >> DTC C0040:29 [Advanced Keyless Entry And Push Button Start System]
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DTC C0040:29 [Advanced Keyless Entry And Push Button Start System]

DESCRIPTION  Erratic signal of brake switch 
DETECTION CONDITION 
  • A combination of the brake switch 1 and 2 signals is abnormal.
POSSIBLE CAUSE 
  • Brake switch connector or terminals malfunction
  • Open circuit or short to ground in brake switch power supply circuit
    • Short to ground in wiring harness between battery positive terminal and brake switch terminal A
    • STOP 15 A fuse malfunction
    • Open circuit in wiring harness between battery positive terminal and brake switch terminal A
  • Open circuit in wiring harness between the following:
    • Brake switch terminal B-Body ground
  • Keyless control module connector or terminals malfunction
  • Short to ground in wiring harness between the following terminals:
    • Brake switch terminal C-Keyless control module terminal 4W
    • Brake switch terminal D-Keyless control module terminal 3R
  • Short to power supply in wiring harness between the following terminals:
    • Brake switch terminal D-Keyless control module terminal 3R
  • Open circuit in wiring harness between the following terminals:
    • Brake switch terminal C-Keyless control module terminal 4W
    • Brake switch terminal D-Keyless control module terminal 3R
  • Brake switch malfunction
  • Keyless control module malfunction
G07874856
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.
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.
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.
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.
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.
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.
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 ).
No Repair or replace the wiring harness for a possible open circuit, then go to the next step.
8 VERIFY TROUBLESHOOTING COMPLETED 
Yes Replace the keyless control module, then go to the next step.
(See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION ).
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] ).
No DTC troubleshooting completed.