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Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Mazda B4000, 2002 Mazda B3000, and 2002 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed, go to next step.

  2. DTC P1432: Check VPWR At THTRC Harness Connector

    Disconnect thermostat harness connector. With KOEO, measure voltage of VPWR circuit (Light Blue/Orange wire) between thermostat harness connector and battery ground. See Fig 1 . If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair VPWR circuit. See WIRING DIAGRAMS article. Go to step  6 .
    Fig 1: Identifying THTRC Connector Circuits
    G00155553Courtesy of MAZDA MOTORS CORP.

  3. Check Thermostat Resistance

    Turn ignition off. Measure resistance of thermostat at thermostat connector (component side). If resistance is 14-16 ohms, go to next step. If resistance is not 14-16 ohms, replace faulty thermostat. Go to step  6 .

  4. Check THTRC Circuit For Open In Harness

    Disconnect PCM connector. Install breakout box, leaving PCM disconnected. Measure resistance of THTRC circuit (Dark Blue wire) between breakout box terminal No. 46 and thermostat harness connector. See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit. See WIRING DIAGRAMS article. Go to step  6 .

  5. Check THTRC Circuit For Short To Ground Or VPWR In Harness

    Measure resistance between breakout box terminals No. 46 and 71 and 97 (VPWR circuit). Record reading. Measure resistance between breakout box terminals No. 46 and 76, 77 and 103 (PWR GND circuit). If resistance is more than 10,000 ohms:
    • For Continuous DTC P1432, problem is intermittent. See INTERMITTENT  under SYSTEM TESTS.
    • For KOEO or KOER DTC P1432, replace faulty PCM. Go to next step.
    If resistance is 10,000 ohms or less, repair short to VPWR or PWR GND. See WIRING DIAGRAMS article. Go to next step.

  6. Verify Trouble Shooting Of DTCs Completed

    Reconnect all electrical connectors. 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 DTCs are set, trouble shooting is complete.
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