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Home › Mazda › 2003 › B4000 Base, Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0703 Or DTC P1703 › Diagnostic Procedures

Diagnostic Procedures

  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed:
    • If brake pedal was applied during KOEO Self-Test, perform KOEO again and avoid applying brake pedal during test.
    • If brake pedal was not applied and released during KOER Self-Test, perform KOER again and make sure to apply and release brake pedal.
    • For KOEO DTC P0703 or P1703, go to next step.
    • For KOER DTC P0703 or P1703, go to step  3 .
  2. DTCs P0703 & P01703: Check Operation Of Stoplights -  While observing stoplights, apply and release brake pedal several times. If stoplights operate normally, go to next step. If stoplights do not operate properly:
    • For stoplights inoperable, go to step  4 .
    • For stoplights always on, go to step  6 .
  3. Check For PCM BPP/BOO PID Cycling -  With KOEO, access BPP/BOO PID with scan tool. While observing BPP/BOO PID, apply and release brake pedal several times. If BPP/BOO PID cycles ON/OFF, go to INTERMITTENT  testing under SYSTEM TESTS. If BPP/BOO PID does not cycle ON/OFF, go to step  9 .
    4. NOTE: Before performing next test step, verify stoplight bulbs are okay.
    Fig 1: Identifying BPP Switch Circuits
    G00155550Courtesy of MAZDA MOTORS CORP.
  4. Check For Power To BPP Switch -  Disconnect BPP switch 5-pin harness connector. Measure B+ input voltage between No. 9 fuse (7.5-amp) at BPP switch and chassis ground. See Fig 1 . If voltage reading is more than 10 volts, go to step  5 . If voltage reading is 10 volts or less, verify integrity of No. 9 fuse (7.5-amp) for B+ circuit to BPP switch. If No. 9 fuse (7.5-amp) is okay, repair open B+ circuit. If No. 9 fuse (7.5-amp) is open, check B+ circuit, BPP circuit, stoplight PWR circuit and any other associated circuits for short to ground. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. Repair as necessary. After repair, go to step  10 .
  5. Verify Integrity Of BPP Switch -  Connect DVOM leads to No. 9 fuse (7.5-amp) and GND circuits of BPP switch. See Fig 1 . While observing DVOM, apply brake pedal. If resistance reading is less than 5 ohms, repair open circuit between BPP switch and stoplight switch ground. After repair, go to step  10 . If resistance reading is 5 ohms or more, replace faulty BPP switch. After repair, go to step  10 .
  6. Verify BPP Switch Is Not Always Closed -  Turn ignition off. Disconnect BPP switch 5-pin harness connector. Turn ignition on. Observe stoplights. If stoplights are still on, go to next step. If stoplights are now off, verify proper installation of BPP switch. If installation is okay, replace faulty BPP switch. After repair, go to step  10 .
  7. Check For Short To Power In PCM -  Turn ignition off. Disconnect PCM 104-pin harness connector. Turn ignition on. Observe stoplights. If stoplights are still on, go to next step. If stoplights are now off, replace faulty PCM. After repair, go to step  10 .
  8. Check Stoplight Circuit For Short To Power In Harness -  Disconnect all modules (one at a time) that are associated with stoplight circuit (PCM, cruise control, GEM, 4WABS). After disconnecting each module, turn ignition on and observe stoplights. Turn ignition off. Repeat ignition cycling until each module has been disconnected or stoplights are off. If stoplights turn off when any of the modules are disconnected, go to appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT. If stoplights do not turn off when modules are disconnected, repair short to power in stoplight circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  10 .
  9. Check For BPP Circuit Cycling -  Turn ignition off. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector only. See Figure . Measure voltage between breakout box terminals No. 92 (BPP circuit) and No. 77 (PWR GND circuit) while applying and releasing brake pedal. If voltage reading cycles, replace faulty PCM. After repair, go to next step. If voltage reading does not cycle, repair open BPP circuit (Red/Light Green wire) to PCM 104-pin harness connector terminal No. 92. After repair, go to next step.
  10. Verify Trouble Shooting Of DTCs Completed -  Reconnect all electrical connectors. Clear DTC from PCM memory. Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If same DTC is present, replace faulty PCM. Repeat QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTC is present, trouble shooting is complete.
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