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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 69 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0230, DTC P0231, DTC P0232 Or DTC P1641 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Mazda Tribute. 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 next step.
    • 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 relay. Turn ignition on, engine off. Measure VPWR circuit voltage at fuel pump relay 5-pin connector in battery junction box. See Fig 1. Turn ignition off. If voltage reading was more than 10.5 volts, go to next step. If voltage reading was not as specified, repair open in VPWR circuit (Red wire) between PCM power relay and fuel pump relay 5-pin connector terminal No. 2 in battery junction box. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24.
    Fig 1: Identifying Fuel Pump Relay 5-Pin Connector Terminals & Fuel System Circuits
    G99A02631Courtesy of FORD MOTOR CO.
  3. Check Fuel Pump Relay -  Measure resistance between fuel pump relay terminals No. 1 and 2. Resistance reading should be 40-120 ohms. Measure resistance between fuel pump relay terminals No. 3 and 5. Resistance reading should be more than 10,000 ohms. Check for continuity between fuel pump relay terminals No. 3 and 4. There should be continuity. If all resistance checks are as specified, go to next step. If any resistance checks are not as specified, replace fuel pump relay. After repair, go to step  24.
  4. Check FP Circuit For Short To Power In Harness -  Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector only. See Figure. Turn ignition on, engine off. Measure voltage between ground and breakout box terminal No. 54 (2.0L) or terminal No. 80 (3.0L). Turn ignition off. If voltage reading was less than 1.0 volt, go to next step. If voltage reading was not as specified, repair short circuit to power in Blue/Orange wire between PCM 104-pin harness connector terminal No. 54 (2.0L) or terminal No. 80 (3.0L) and fuel pump relay 5-pin connector terminal No. 1 in battery junction box. See Fig 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 from DLC. Measure resistance between ground and breakout box terminal No. 54 (2.0L) or terminal No. 80 (3.0L). If all resistance readings are more than 10,000 ohms, go to next step. If all resistance readings are not as specified, repair short circuit in Blue/Orange wire between PCM 104-pin harness connector terminal No. 54 (2.0L) or terminal No. 80 (3.0L) and fuel pump relay 5-pin connector terminal No. 1 in battery junction box. See Fig 1. After repair, go to step  24.
  6. Check FP For Open Circuit -  Measure resistance of FP circuit between breakout box terminal No. 54 (2.0L) or terminal No. 80 (3.0L) and fuel pump relay 5-pin connector terminal No. 1 in battery junction box. If resistance reading is less than 5 ohms and DTC P0231 or P0232 is present with P0230, go to next step. If resistance reading is less than 5 ohms and DTC P0231 or P0232 is not present with P0230, replace PCM. After repair, go to step 24. If resistance reading is not as specified, repair open circuit in Blue/Orange wire between PCM 104-pin harness connector terminal No. 54 (2.0L) or terminal No. 80 (3.0L) and fuel pump relay 5-pin connector terminal No. 1 in battery junction box. After repair, go to step  24.
  7. Check Fuel Pump Primary Circuit Inside The PCM -  Remove breakout box. Reconnect PCM. Reconnect fuel pump relay. Reconnect scan tool to DLC. Turn ignition on, engine off. Access FPF PID on scan tool. If FPF PID is not YES, go to next step. If FPF PID is YES, turn ignition off. Replace PCM. After repair, go to step  24.
    8. NOTE: During next step, scan tool must be connected to a reliable power source that is powered with ignition in START position (e.g., directly to vehicle battery). Also verify that vehicle battery is fully charged.
  8. Check The Fuel Pump Primary Circuit Inside PCM While Cranking Engine -  While observing FPF PID, crank engine. If FPF PID is YES during cranking, turn ignition off. Replace PCM. After repair, go to step  24. If FPF PID is not YES, turn ignition off. Fuel pump primary circuit is okay in harness and PCM. If DTC P0231 is present, go to step  18. If DTC P0232 is present, go to next step.
  9. Check Engine Start -  If engine starts, go to next step. If engine does not start, go to step  14.
  10. Verify That Fuel Pump Is Off -  Turn ignition on, engine off. Wait 5 seconds. Listen for motor noise from fuel pump (it may be necessary to listen near fuel tank). If fuel pump is off, turn ignition off and go to step  12. If fuel pump is on, turn ignition off and go to next step.
  11. Check For Fuel Pump Relay Always Closed -  Disconnect fuel pump relay from battery junction box. Turn ignition on, engine off. If fuel pump is off, turn ignition off. Replace fuel pump relay. After repair, go to step  24. If fuel pump is on, turn ignition off. Repair short to power in fuel pump PWR/FPM circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24.
  12. Check For Open Fuel Pump Monitor Circuit -  Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector only. See Figure. Disconnect fuel pump relay from battery junction box. Measure resistance of FP PWR circuit between breakout box terminal No. 40 and fuel pump relay 5-pin connector terminal No. 5 (Dark Green/Yellow wire). If resistance reading is less than 5 ohms, go to next step. If resistance reading is not as specified, repair open circuit in Dark Green/Yellow wire between fuel pump relay 5-pin connector terminal No. 5 and PCM 104-pin harness connector terminal No. 40. After repair, go to step  24.
  13. Check Fuel Pump Monitor Circuit In PCM -  Remove breakout box. Reconnect PCM 104-pin harness connector and fuel pump relay. Turn ignition on, engine off. Access FPM PID on scan tool. If FPM PID is OFF, fuel pump module circuit is okay in harness and PCM. Disregard DTC P0232 at this time. Go to step  24. If FPM PID is not OFF, replace PCM. After repair, go to step  24.
  14. Check Inertia Fuel Shutoff Switch -  Locate and disconnect Inertia Fuel Shutoff (IFS) switch 3-pin harness connector after verifying switch is reset. Measure resistance between IFS switch terminals No. 1 and 2. See Fig 2. If resistance reading is less than 5 ohms, go to next step. If resistance reading is not as specified, replace IFS 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 -  Disconnect fuel pump relay from battery junction box. Measure resistance of FP PWR circuit (Dark Green/Yellow wire) between fuel pump relay 5-pin connector terminal No. 5 and IFS switch 3-pin harness connector terminal No. 1. See Fig 1 and Fig 2 . If resistance reading is less than 5 ohms, reconnect fuel pump relay. Go to next step. If resistance reading is not as specified, repair open circuit in Dark Green/Yellow wire between fuel pump relay 5-pin connector terminal No. 5 and IFS switch 3-pin harness connector terminal No. 1. 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 tank unit 4-pin harness connector. Measure resistance of FP GND circuit between ground and fuel tank unit 4-pin harness connector terminal No. 3 (Black wire). Measure resistance of FP PWR circuit (Pink/Black wire) between IFS switch 3-pin harness connector terminal No. 2 and fuel tank unit 4-pin harness connector terminal No. 1. See Fig 3. If resistance reading is less than 5 ohms, go to next step. If resistance reading is not as specified, repair open circuit in suspect wire between IFS switch 3-pin harness connector and fuel tank unit 4-pin harness connector. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24.
    Fig 3: Identifying Fuel Tank Unit 4-Pin Harness Connector Terminals
    G00110116Courtesy of MAZDA MOTORS CORP.
  17. Check Internal Resistance Of Fuel Pump -  Measure internal resistance of fuel pump between fuel tank unit 4-pin connector FP PWR terminal No. 1 and ground terminal No. 3. If resistance reading is less than 10 ohms, all fuel pump circuits are okay. Verify test step results. If all test steps are okay, reconnect all disconnected connectors. Disregard DTC P0232 at this time. Go to step  24. If resistance reading is not as specified, replace fuel pump. After repair, go to step  24.
  18. Check Engine Start -  If KOEO DTC P0230 is also present and has not been diagnosed, go to step  21 (to check primary fuel pump circuits first). If engine does not start, go to next step. If engine starts, go to step  12.
  19. Check B+ Voltage To Fuel Pump Relay -  Disconnect fuel pump relay located in battery junction box. Measure B+ circuit voltage at fuel pump relay 5-pin connector terminal No. 3 (Orange wire). See Fig 1. If voltage reading is more than 10.5 volts, go to next step. If voltage reading is not as specified, check for burned No. 6 fuse (20-amp) in battery junction box. If fuse is okay, repair open circuit between positive battery terminal and fuel pump relay 5-pin connector terminal No. 3 (Orange wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If fuse/fuse link is burned, check B+ (Orange wire) and FP PWR (Dark Green/Orange wire) circuits for short to ground before replacing. After repair, go to step  24.
  20. Check For Open FP PWR Circuit Between Fuel Pump Relay & Ground Point 2  Measure resistance of FP PWR circuit between fuel pump relay 5-pin connector terminal No. 5 and negative battery terminal. If resistance reading is less than 10 ohms, replace fuel pump relay. After repair, go to step  24. If resistance reading is not as specified, repair open circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24.
    21. NOTE: During following step, FPF PID will read YES when an open is detected because PCM will not detect VPWR voltage on PCM terminal No. 54 (2.0L) or terminal No. 80 (3.0L).
    NOTE: When testing FP circuit with engine running, also monitor FPM PID. This is because not all FP circuit failures can be detected using only FPF PID.
  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 that PCM detects VPWR voltage through fuel pump relay coil and FP circuit to PCM. Observe FPF PID for an indication of a fault while performing following:
    • Shake, wiggle, bend FP circuit between PCM and fuel pump relay.
    • Shake, wiggle, bend VPWR circuit between Electronic Control Power Relay (ECPR) and fuel pump relay.
    • Lightly tap fuel pump relay to simulate road shock.
    • Inspect PCM and fuel pump relay connectors for corrosion or damaged terminals.
    If a fault is indicated, isolate fault and repair as necessary. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  24. If fault is not indicated, problem is intermittent. Refer to INTERMITTENT  testing under SYSTEM TESTS.
  22. Continuous Memory DTC P0231: Check Harness Circuits -  Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) between PCM harness connector and PCM. See Figure. Install fused jumper wire between breakout box terminals No. 51 and No. 54 (2.0L) or terminal No. 80 (3.0L). Connect DVOM between breakout box terminals No. 40 and No 51. Turn ignition on, engine off. Fuel pump will turn on and voltage will be more than 10 volts. Observe voltage for an indication of a fault while performing following:
    • Shake, wiggle, bend B+ circuit to fuel pump relay.
    • Lightly tap fuel pump relay to simulate road shock.
    • Shake, wiggle bend FP PWR circuit between fuel pump relay and FPM splice.
    Turn ignition off. Inspect fuel pump relay connector for corrosion, damaged terminals, etc. If a fault is indicated, isolate fault and repair as necessary. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If a fault is not indicated, problem is intermittent. Refer to INTERMITTENT  testing under SYSTEM TESTS.
  23. Continuous Memory DTC P0232: Check Fuel Pump Secondary Circuits -  If continuous memory DTC P0230 is also present, go to step  21. Turn ignition on, engine off. Access FPM PID on scan tool. Observe FPM PID for an indication of a fault while performing following (FPM PID will turn ON when an open or short to power is detected):
    • Shake, wiggle, bend FP PWR circuit (Dark Green/Yellow wire) between fuel pump relay FP PWR terminal No. 5 and fuel tank unit 3-pin harness connector terminal No. 2.
    • Shake, wiggle, bend fuel pump ground circuit from fuel tank unit to ground.
    • Shake, wiggle, bend FPM circuit between PCM and the splice to FP PWR circuit.
    • Lightly tap fuel pump, fuel pump relay and IFS switch to simulate road shock.
    If fault is indicated/found, isolate fault and repair as necessary. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step. If fault is not found, problem is intermittent. Refer to INTERMITTENT  testing under SYSTEM TESTS.
  24. Verify Trouble Shooting Of DTCs Completed  Reconnect all disconnected connectors. Clear DTCs from PCM memory using scan tool. Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If same DTC is present, replace faulty PCM. Repeat QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If same DTC is not present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are set, procedure is complete.
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