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DTC P0703: Brake Switch Malfunction: Testing

NOTE: Ensure freeze frame data has been recorded. Check for service bulletins and on-line information.
  1. Using scan tool, access PID/DATA MONITOR. Record PID data for BRK SW. Depress and release brake pedal several times. If PID does not switch, go to next step. If PID switches each time, problem is not present. Check for intermittent problem. See TROUBLE SHOOTING - NO CODES article.
  2. Release brake pedal. If BRK SW PID is on, go to next step. If BRK SW PID is off, go to step  5 .
  3. Disconnect brake switch connector. If BRK SW PID stays on, go to next step. If BRK SW PID turns off, replace brake switch. After repair, go to step  11 .
  4. Check voltage between brake switch harness connector terminal "B" (Green/Yellow wire) and ground. If battery voltage is not present, go to next step. If battery voltage is present, repair short to power on Green/Yellow wire between PCM and brake switch. After repair, go to step  11 .
  5. If BRK SW PID stays off at all times, go to next step. If BRK SW PID does not stay off at all times, go to step  11 .
  6. Turn ignition off. Disconnect brake switch connector. Check connector and terminals. If no problem is found, go to next step. If any problem is found, repair as necessary. After repair, go to step  11 .
  7. Disconnect brake switch connector. Connect a jumper wire between harness connector terminals. If BRK SW PID stays off, go to next step. If BRK SW PID turns on, replace switch. After repair, go to step  11 .
  8. Check voltage between brake switch harness connector terminal "A" (Green wire) and ground. If battery voltage is present, go to next step. If battery voltage is not present, repair open on circuit between battery and brake switch. After repair, go to step  11 .
  9. Turn ignition off. Disconnect PCM connector. PCM is mounted to passenger floor, behind glove box. Check connector and terminals. If no problem is found, go to next step. If any problem is found, repair as necessary. After repair, go to step  11 .
  10. Connect breakout box to harness connector. Leave PCM disconnected. Connect brake switch connector. Turn ignition on. Check voltage between breakout box terminal No. 92 and ground. If battery voltage is present, go to next step. If battery voltage is not present, repair open on circuit between PCM and brake switch. After repair, go to step  11 .
  11. Reconnect all components. Using scan tool, clear DTC. Drive vehicle at more than 37 MPH for one minute. Depress and release brake pedal more than 10 times during drive. Recheck DTCs. If DTC P0703 is present, replace PCM and go to next step. If DTC P0703 is not present, go to next step.
  12. Perform after repair procedure. See AFTER REPAIR PROCEDURE  . If no DTC is present, testing is complete. If any DTC is present, go to appropriate test for diagnosis and repair.
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