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Home >> Mazda >> 2007 >> B4000 SE, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 70 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0230, DTC P0231 Or DTC P0232 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Mazda B4000, 2003 Mazda B3000, and 2003 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:
    • For DTC P0230, go to step  2 .
    • For DTC P0231, go to step  18 .
    • For KOEO DTC P0232, go to step  9 .
    • For Continuous Memory DTC P0230, go to step  21 .
    • For Continuous Memory DTC P0231, go to step  22 .
    • For Continuous Memory DTC P0232, go to step  23 .
  2. Check For VPWR To Fuel Pump Relay -  Disconnect Fuel Pump (FP) relay. With KOEO, measure voltage of VPWR circuit (Red wire, terminal No. 2) at fuel pump relay 5-pin harness connector. See Fig 1 . Turn ignition off. If voltage reading is more than 10.5 volts, go to next step. If voltage reading is 10.5 volts or less, repair open in VPWR circuit (Red wire) between PCM power relay and fuel pump relay. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24 .
    Fig 1: Fuel Pump Relay Connector Circuit Identification
    G00155534Courtesy of MAZDA MOTORS CORP.
    3. NOTE: Refer to molded numbers on fuel pump relay during next step.
  3. Check Fuel Pump Relay -  Measure resistance between FP relay terminals No. 1 and 2. Resistance should be 40-120 ohms. Check continuity between terminals No. 3 and 4. Continuity should be present. Check continuity between terminals No. 3 and 5. Continuity should not be present. If all measurements are okay, go to next step. If any measurement is not okay, replace faulty fuel pump relay. Go to step  24 .
  4. Check FP Circuit For Short To Power In Harness -  Disconnect PCM 104-pin harness connector. Connect breakout box to PCM harness connector only. See Figure . With KOEO, measure voltage between breakout box terminal No. 80 and chassis ground. Turn ignition off. If voltage reading is less than one volt, go to next step. If voltage reading is one volt or more, repair short circuit to power in Light Blue/Orange wire between PCM 104-pin harness connector terminal No. 80 and fuel pump relay 5-pin harness connector terminal No. 1. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24 .
  5. Check FP Circuit For Short To Ground In Harness -  Disconnect scan tool. Measure resistance between breakout box terminal No. 80 and ground. If resistance reading is more than 10,000 ohms, go to next step. If resistance reading is 10,000 ohms or less, repair short circuit in Light Blue/Orange wire between PCM 104-pin harness connector terminal No. 80 and fuel pump 5-pin harness connector terminal No. 1. After repair, go to step  24 .
  6. Check FP For Open Circuit -  Measure resistance of FP circuit (Light Blue/Orange wire) between breakout box terminal No. 80 and FP relay 5-pin harness connector terminal No. 1. If resistance reading is 5 ohms or more, repair open circuit in Light Blue/Orange wire between PCM 104-pin harness connector terminal No. 80 and fuel pump relay 5-pin harness connector terminal No. 1. After repair, go to step  24 . If resistance reading is less than 5 ohms:
    • If KOEO DTC P0231 or P0232 is also set with P0230, go to step  7 .
    • For all others, replace faulty PCM. After repair, go to step  24 .
  7. Check Fuel Pump Primary Circuit Inside PCM -  Remove breakout box. Reconnect PCM 104-pin harness connector and FP relay. Reconnect scan tool to DLC. With KOEO, access FPF PID. If FPF PID status is YES, turn ignition off. Replace faulty PCM. After repair, go to step  24 . If FPF PID status is not YES, go to next step.
  8. Check Fuel Pump Primary Circuit Inside PCM While Cranking Engine -  Scan tool must be connected to a power source (i.e. vehicle battery) that will allow scan tool to be powered when ignition is in START position. Ensure battery is fully charged. Using scan tool, observe FPF PID while cranking engine. If FPF PID status is YES during engine cranking, turn ignition off. Replace faulty PCM. After repair, go to step  24 . If FPF PID status is not YES during engine cranking, turn ignition off. The fuel pump primary circuit is okay in the wiring harness and PCM. If KOEO DTC P0231 is set, go to step  18 . IF KOEO DTC P0232 is set, go to next step.
  9. Check For Engine Start -  Attempt to start engine. If engine starts, go to next step. If engine does not start, go to step  14 .
  10. Verify Fuel Pump Is Off -  Turn ignition on, engine off. Wait 5 seconds. Listen for fuel pump motor noise (it may be necessary to listen near fuel tank). Turn ignition off. If fuel pump ran, go to next step. If fuel pump did not run, go to step  12 .
  11. Check For Fuel Pump Relay Always Closed -  Disconnect FP relay. Put ignition into KOEO position. Listen for fuel pump motor noise (it may be necessary to listen near fuel tank). If fuel pump runs, turn ignition off. Repair short to power in FP PWR circuit (Dark Green/Yellow wire) between FP relay 5-pin harness connector and fuel pump. See Fig 1 . See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24 . If fuel pump does not run, turn ignition off. Replace faulty FP relay. After repair, go to step  24 .
  12. Check For Open Fuel Pump Monitor Circuit -  Turn ignition off. Disconnect PCM 104-pin harness connector. Connect breakout box to PCM harness connector only. See Figure . Disconnect FP relay. Measure resistance of FP PWR circuit (Dark Green/Yellow wire) between breakout box terminal No. 40 and FP relay 5-pin harness connector. See Fig 1 . If resistance reading is less than 5 ohms, go to next step. If resistance reading is 5 ohms or more, repair open circuit in Dark Green/Yellow wire between PCM 104-pin harness connector terminal No. 40 and fuel pump relay 5-pin harness connector terminal No. 5. After repair, go to step  24 .
  13. Check Fuel Pump Monitor (FPM) Circuit In PCM -  Remove breakout box. Reconnect PCM 104-pin harness connector and FP relay. With KOEO access FP M PID and observe. If FP M PID is OFF, no fault was detected. The FPM circuit is okay in the wiring harness and PCM. Disregard DTC P0232 at this time. Go to step  24 . If FP M PID is not OFF, replace faulty PCM. After repair, go to step  24 .
  14. Check Inertia Fuel Shutoff Switch -  Locate and disconnect IFS switch after verifying switch is reset. IFS switch is mounted on lower firewall, above carpet, behind right side of instrument panel. Measure resistance between IFS switch terminals "C" and "NC". See Fig 2 . If resistance reading is less than 5 ohms, go to next step. If resistance reading is 5 ohms or more, replace faulty IFS switch or reset switch. After repair, go to step  24 .
    Fig 2: Identifying Inertia Fuel Shutoff Switch 3-Pin Harness Connector Terminals
    G00159003Courtesy of MAZDA MOTORS CORP.
  15. Check For Open FP PWR Circuit Between IFS Switch & Fuel Pump Relay -  Turn ignition off. Disconnect fuel pump relay. Measure resistance of FP PWR circuit (Dark Green/Yellow wire) between fuel pump relay 5-pin harness connector terminal No. 5 and IFS switch 3-pin harness connector. If resistance reading is less than 5 ohms, reconnect fuel pump relay. Go to next step. If resistance reading is 5 ohms or more, repair open FP PWR circuit (Dark Green/Yellow wire) between fuel pump relay 5-pin harness connector terminal No. 5 and IFS switch 3-pin harness connector. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24 .
  16. Check For Open FP GND Circuit & FP PWR Circuit (Between IFS Switch & Fuel Pump) -  Disconnect Fuel Pump (FP) connector. Measure resistance of FP GND circuit (Black wire) between FP 4-pin harness connector and chassis ground. Record reading. Measure resistance of FP PWR circuit (Dark Green/Yellow wire) between IFS switch 3-pin harness connector and FP 4-pin harness connector. Record reading. If each resistance reading is less than 5 ohms, go to next step. If resistance reading is 5 ohms or more for either reading, repair open circuit. After repair, go to step  24 .
  17. Check Internal Resistance of Fuel Pump -  Measure internal resistance of fuel pump between FP PWR circuit (Pink/Black wire) and ground circuit (Black wire) at FP 4-pin connector. If resistance reading is less than 10 ohms, all fuel pump circuits are okay. Reconnect all components. Disregard DTC P0232 at this time. Go to step  24 . If resistance reading is 10 ohms or more, replace faulty fuel pump. After repair, go to step  24 .
  18. Check Engine Start -  If DTC P0230 is also set and has not been diagnosed, go to step  21 to check primary fuel pump circuits first. If DTC P0230 is not set, attempt to start engine. If engine starts, go to step  12 . If engine does not start, go to next step.
  19. Check B+ Voltage To Fuel Pump Relay -  Disconnect FP relay. Measure B+ circuit (Light Blue/Orange wire) voltage at FP relay 5-pin harness connector. If voltage reading is more than 10.5 volts, go to next step. If voltage reading is 10.5 volts or less, verify integrity of No. 23 fuse (20-amp) in engine compartment fuse box. If fuse is okay, repair open circuit in Light Blue/Orange wire between No. 23 fuse (20-amp) and fuel pump relay 5-pin harness connector. After repair, go to step  24 . If fuse is open, check B+ (Light Blue/Orange wire) and FP PWR (Dark Green/Yellow wire) circuits for short to ground before replacing fuse. After repair, go to step  24 .
  20. Check For Open FP PWR Circuit Between Fuel Pump Relay & Ground Point 2 -  Turn ignition off. Measure resistance of FP PWR circuit (Dark Green/Yellow wire) between FP relay 5-pin harness connector and negative battery terminal. If resistance reading is less than 10 ohms, replace faulty FP relay. After repair, go to step  24 . If resistance reading is 10 ohms or more, repair open circuit in Dark Green/Yellow wire between PCM 104-pin harness connector terminal No. 40, fuel pump relay 5-pin harness connector terminal No. 5 and IFS switch harness connector. Go to step  24 .
  21. Continuous Memory DTC P0230: Check Fuel Pump Primary Circuits -  Connect scan tool to DLC. Turn ignition on engine off. Wait 5 seconds. Access FPF PID. FPF PID will be NO, indicating PCM detects VPWR voltage through FP relay coil and FP circuit to PCM. Observe FPF PID for indication of a fault while shaking, wiggling and bending FP circuit between PCM and fuel pump relay. Also shake, wiggle and bend VPWR circuit between Electronic Control Power relay and FP relay. Lightly tap FP relay. Turn ignition off. If an open circuit is present anywhere in wiring, FPF PID will change to YES because PCM will not detect VPWR voltage on PCM terminal No. 80. Check PCM and FP relay connectors for corrosion or damaged terminals. If a fault is indicated, isolate and repair as necessary. After repair, go to step  24 . If a fault is not indicated, fault cannot be duplicated at this time. See INTERMITTENT  testing under SYSTEM TESTS with FPM PID data and list of possible causes. When testing FP circuit with engine running, also observe FPM PID. Not all FP circuit failures may be detected using only FPF PID.
  22. Continuous Memory DTC P0231: Check Harness Circuits -  Connect breakout box between PCM and PCM 104-pin harness connector. See Figure . Install a fused jumper wire between breakout box terminals No. 80 and 51. Turn ignition on. Measure voltage between breakout box terminals No. 40 and 51. Fuel pump will run and voltage will be more than 10 volts. Observe voltage for indication of a fault while shaking, wiggling and bending B+ circuit to fuel pump relay. Also shake, wiggle and bend wiring for FP PWR circuit between FP relay and FPM splice. Lightly tap FP relay. If an open circuit is present anywhere in wiring, turn ignition off. If a fault is located, isolate and repair as necessary. Go to step  24 . If a fault is not located, fault cannot be duplicated at this time. See INTERMITTENT  testing under SYSTEM TESTS with FPM PID data and list of possible causes.
  23. Continuous Memory DTC P0232: Check Fuel Pump Secondary Circuits -  Turn ignition on, engine off. Access FPM PID. FPM PID will change to ON, indicating PCM detects an open or short circuit to power. Observe FPM PID for indication of a fault while shaking, wiggling and bending following:
    • FP PWR circuit between FP relay and fuel pump.
    • FP ground circuit between fuel pump and ground.
    • FPM circuit between PCM and splice to FP PWR circuit.
    Lightly tap on fuel pump, FP relay and IFS switch. Turn ignition off. If a fault is located, isolate and repair as necessary. After repair, go to next step. If a fault is not located, fault cannot be duplicated at this time. See INTERMITTENT  testing under SYSTEM TESTS.
  24. Verify Trouble Shooting Of DTCs Completed -  Make sure all electrical connectors are reconnected. Clear DTCs from PCM memory using scan tool. Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If the same DTC is present, replace faulty PCM. Repeat QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTCs are present, test is complete.
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