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.
- If QUICK TEST was not performed, go to QUICK TEST
under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed:
- For Continuous Memory DTC P1474, go to step 7 .
- For all others, go to next step.
- Check VPWR Voltage To Fan Relay
Disconnect fan control relay. With KOEO, measure VPWR circuit (Red wire) voltage at fan relay control harness connector. See Fig 1 . If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open VPWR circuit to fan control relay. See WIRING DIAGRAMS article. Go to step 9 . - Check For FC Circuit Cycling
Connect a non-powered test light between VPWR circuit (Red wire) and FC circuit (Orange/White wire) at fan control relay harness connector. See Fig 1 . While observing test light, turn climate control selector switch from OFF to DEFROST several times. If test light turns on and off, replace faulty fan control relay. Go to step 9 . If test light does not turn on and off, repeat test step to verify results. If results are still the same, remove test light. Turn ignition off. Go to next step. - Check Fan Control (FC) Circuit For Short To Power In Harness
Disconnect PCM connector. With KOEO, measure voltage between fan relay harness connector FC circuit (Orange/White wire) and ground. See Fig 1 . If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short circuit. See WIRING DIAGRAMS article. Go to step 9 . - Check FC Circuit For Short To Ground In Harness
Turn ignition off. Disconnect scan tool. Measure resistance between fan relay harness connector FC circuit (Orange/White wire) and ground. If resistance is more than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair short circuit. See WIRING DIAGRAMS article. Go to step 9 . - Check For Open FC Circuit
Install breakout box, leaving PCM disconnected. Measure resistance of FC circuit (Orange/White wire) between breakout box terminal No. 45 and fan control relay harness connector. See Fig 1 . If resistance is less than 5 ohms, replace faulty PCM. Go to step 9 . If resistance is 5 ohms or more, repair open circuit. See WIRING DIAGRAMS article. Go to step 9 . - Check Fan Control (FC) Circuit For Open Or Short To Power
Verify A/C and defrost are turned off. Disconnect cooling fan connector. Connect a non-powered test light between VPWR circuit (Red wire) and ground at cooling fan harness connector. See Fig 1 . With KOEO, turn climate control selector switch from OFF to DEFROST. Observe test light for an indication of a fault while completing the following (test light will turn off indicating a fault):- Shake, wiggle, and bend FC circuit between PCM and FC relay.
- Shake, wiggle and bend VPWR circuit (Red wire) to FC relay.
- Lightly tap on FC relay to simulate road shock.
- Check FC Circuit For Short To Ground
Turn climate control selector switch from DEFROST to OFF. Observe test light for an indication of a fault while shaking, wiggling, and bending FC circuit between PCM and FC relay. Lightly tap on FC relay to simulate road shock. If a fault is indicated, isolate and repair wiring harness as necessary. See WIRING DIAGRAMS article. Go to next step. If a fault is not indicated, problem is intermittent. See INTERMITTENT under SYSTEM TESTS. - Verify Trouble Shooting Of DTCs Completed
Reconnect all electrical connectors. Using scan tool, clear DTC memory. Using scan tool, retrieve DTCs. See QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If same DTC is present, replace faulty PCM and 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.