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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 61 (Engine Controls [Self-Diagnostics 3.0L]) >> Diagnostic Tests >> DTC P0703: Brake Switch No. 1 - Input Malfunction >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
  1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
  2. Verify Related Repair Information Availability -  Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
  3. Inspect Brake Switch Connector For Poor Connection -  Turn ignition off. Disconnect brake switch 4-pin harness connector. Inspect for poor connection (such as damaged, pulled-out terminals or corrosion). If there are no malfunctions, go to next step. If there are any malfunctions, repair or replace suspected terminal. After repair, go to step  9.
  4. Inspect Brake Switch No. 1 Power Circuit For Open Circuit -  Turn ignition on, engine off. Measure voltage between brake switch 4-pin harness connector terminal "B" (Green/White wire) and body ground. See Fig 1. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Green/White wire between positive battery terminal and brake switch 4-pin harness connector terminal "B" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step  9.
    Fig 1: Identifying Brake Switch No. 1 Circuits & Harness Connector Terminals
    G00221556Courtesy of MAZDA MOTORS CORP.
  5. Inspect Brake Switch No. 1 Signal Circuit For Short To Power -  Turn ignition on, engine off. Measure voltage between brake switch 4-pin harness connector terminal "D" (Green/Yellow wire) and body ground. If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Green/Yellow wire between brake switch 4-pin harness connector terminal "D" and PCM 104-pin harness connector terminal No. 32 or replace wire harness. After repair, go to step  9.
  6. Inspect PCM Connector For Poor Connection -  Turn ignition off. Disconnect PCM 104-pin harness connector. Inspect for poor connection (such as damaged, pulled-out terminals or corrosion). If connections are okay, go to next step. If any malfunctions are present, repair or replace faulty terminal. After repair, go to step  9.
  7. Inspect Brake Switch No. 1 Signal Circuit For Open Circuit -  Check for continuity in Green/Yellow wire between brake switch 4-pin harness connector terminal "D" and PCM 104-pin harness connector terminal No. 32. See Fig 1. If continuity is present, go to next step. If continuity is not present, repair open circuit in Green/Yellow wire between brake switch 4-pin harness connector terminal "D" and PCM 104-pin harness connector terminal No. 32 or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step  9.
  8. Inspect Brake Switch No. 1 -  Inspect brake switch No. 1. Refer to BRAKELIGHT SWITCH under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If brake switch is okay, go to next step. If brake switch is faulty, replace brake switch. After repair, go to next step.
  9. Verify Trouble Shooting Of DTC P0703 Is Completed -  Make sure to reconnect all disconnected connectors. Clear DTC from memory using WDS or equivalent. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Drive vehicle at 18.6 MPH or more. Depress and release brake pedal more than 8 times while driving vehicle. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
  10. Verify After Repair Procedure -  Using scan tool, perform After Repair Procedure. See AFTER REPAIR PROCEDURE . If any DTCs are present, go to appropriate DTC inspection. Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are present, trouble shooting is complete.
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