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DTC P0703

DTC P0703 Brake switch input circuit problem
DETECTION CONDITION 
  • The PCM monitors the input signal from the brake switch when the following conditions are met. If the input signal does not change white alternately accelerating and decelerating 8 times, the PCM determines that there is a brake switch input circuit malfunction.

MONITORING CONDITIONS 
  • Vehicle speed: decelerating more than 30 km/h {19 mph} to 0 km/h {0 mph} 
  • Deceleration: more than 4 km/h {2 mph} pers 

Diagnostic support note 
  • This is a continuous monitor (CCM).
  • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle white the DTC for the same malfunction has been stored in the PCM.
  • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
  • FREEZE FRAME DATA (Mode 2/Mode 12) is available.
  • The DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • Brake switch connector or terminals malfunction
  • Open circuit in wiring harness between brake switch terminal C and body ground
  • Short to ground in wiring harness between brake switch terminal A and PCM terminal 1AB
  • Brake switch malfunction
  • PCM connector or terminals malfunction
  • Open circuit in wiring harness between brake switch terminal A and PCM terminal 1 AB
  • PCM malfunction
G07878133
DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA (MODE 12) HAS BEEN RECORDED 
  • Has the FREEZE FRAME DATA (Mode 12) been recorded?
 Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 12) on the repair order, then go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY 
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
 Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT BRAKE SWITCH CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Disconnect the brake switch connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the connector and/or terminals, then go to Step 9.
No Go to the next step.
4 INSPECT BRAKE SWITCH GROUND CIRCUIT FOR OPEN CIRCUIT 
  • Brake switch connector is disconnected.
  • Turn the ignition switch off.
  • Inspect for continuity between brake switch terminal C (wiring harness-side) and body ground.
  • 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 9.
5 INSPECT BRAKE SWITCH SIGNAL CIRCUIT FOR SHORT TO GROUND 
  • Brake switch connector is disconnected.
  • Turn the ignition switch off.
  • Inspect for continuity between brake switch terminal A (wiring harness-side) and body ground.
  • Is there continuity?
 Yes If the short to ground circuit could be detected:
  • Repair or replace the wiring harness for a possible short to ground.

If the short to ground circuit could not be detected:
Go to Step 9.
No Go to the next step.
6 INSPECT BRAKE SWITCH 
CAUTION:
  • If the brake switch is removed from the brake pedal or the interlock unit, its proper functioning cannot be guaranteed when reinstalled. Therefore, inspect the brake switch with it still installed, or replace the brake switch if it is removed.
 Yes Replace the brake switch, then go to Step 9.
(See BRAKE PEDAL REMOVAL/INSTALLATION ).
No Go to the next step.
7 INSPECT PCM CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the connector and/or terminals, then go to Step 9.
No Go to the next step.
8 INSPECT BRAKE SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT 
  • Brake switch and PCM connectors are disconnected.
  • Turn the ignition switch off.
  • Inspect for continuity between brake switch terminal A (wiring harness-side) and PCM terminal 1AB (wiring harness-side).
  • Is there continuity?
 Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9 VERIFY TROUBLESHOOTING OF DTC P0703 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS.

    (See AFTER REPAIR PROCEDURE ).

  • Perform the following procedures 8 times alternately.
    • Drive the vehicle more than 30 km/h {19 mph}  .
    • Decelerate to 0 km/h {0 mph} within 7 s  .
  • Perform the Pending Trouble Code Access Procedure.

    (See ON-BOARD DIAGNOSTIC TEST ).

  • Is the PENDING CODE same as DTC present?
 Yes Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION ).
No Go to the next step.
10 VERIFY AFTER REPAIR PROCEDURE 
 Yes Go to the applicable DTC inspection.
(See DTC TABLE ).
No DTC troubleshooting completed.
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