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, go to next step.
- DTC P1451: Check VPWR Voltage To Canister Vent Solenoid
Turn ignition off. Disconnect EVAP CV solenoid. Connect a non-powered test light between CV circuit (Violet/White wire) and VPWR circuit (Light Blue/Orange wire) at EVAP CV solenoid harness connector. See Fig 1 . With KOEO, using scan tool, select Diagnostic Data Link. Select PCM. Select PID/Data Monitor and Record. Attempt to close and open EVAP CV solenoid driver in PCM by accessing Output Test Mode. Select ALL OFF mode. Cycle START button on and off, and observe test light. If test light cycles on and off, turn ignition off. Go to next step. If test light does not cycle on and off: - Check CV Solenoid Resistance
Measure EVAP CV solenoid resistance. If resistance is 45-65 ohms, unable to identify fault at this time. See INTERMITTENT under SYSTEM TESTS. If resistance is not 45-65 ohms, replace faulty EVAP CV solenoid. Go to step 10 . - Check For Open VPWR Circuit Between EVAP CV Solenoid & Power Relay
Measure voltage of VPWR circuit between EVAP CV solenoid harness connector and battery negative terminal. See Fig 1 . If voltage is more than 10.5 volts, turn ignition off. Go to next step. If voltage is 10.5 volts or less, turn ignition off. Repair open circuit. See WIRING DIAGRAMS article. Go to step 10 . - Check VPWR Circuit For Opening In Harness
Disconnect PCM connector. Install breakout box, leaving PCM disconnected. Measure resistance of VPWR circuit (Light Blue/Orange wire) between breakout box terminal No. 71 and EVAP CV solenoid 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 10 . - Check EVAP CV Circuit For Open In Harness
Measure resistance of EVAP CV circuit (Violet/White wire) between breakout box terminal No. 67 and EVAP CV solenoid harness connector. If resistance is less than 5 ohms, replace faulty PCM. Go to next step. If resistance is 5 ohms or more, repair open circuit. See WIRING DIAGRAMS article. Go to step 10 . - Check EVAP CV Circuit For Short To VPWR
With KOEO, measure voltage of EVAP CV circuit between EVAP CV solenoid harness connector and chassis ground. If voltage is less than one volt, replace faulty PCM. Go to step 10 . If voltage is one volt or more, repair short to VPWR. See WIRING DIAGRAMS article. Go to step 10 . - Check Circuit For Short To PWR GND In Harness
Disconnect PCM connector. Disconnect scan tool. Measure resistance of EVAP CV circuit between EVAP CV solenoid harness connector and battery negative terminal. 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 10 . - Check Circuit For Short To Power
Reconnect scan tool. With KOEO, measure voltage between EVAP CV circuit between EVAP CV solenoid harness connector and battery ground. Turn ignition off. If voltage is less than one volt, replace faulty PCM. Go to next step. If voltage is one volt or more, repair short circuit to VPWR, VREF or chassis ground. See WIRING DIAGRAMS article. Go to next step. - 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.