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Home >> Mazda >> 2013 >> 5 Grand Touring >> Repair and Diagnosis >> External Pages >> Different car >> Section 67 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0300, DTC P0301, DTC P0302, DTC P0303, DTC P0304, DTC P0305, DTC P0306, DTC P0315 Or DTC P0316 >> 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 and any other DTCs are present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If DTC P0300 only is present, go to step  18. For DTCs P0301-P0306, P3015 and P3016, go to next step.
  2. Check/Compare PID Values -  Turn all accessories off (A/C, heater, etc.). Turn ignition on, engine off (KOEO). Access DPFEGR PID with scan tool and record values. Start engine (KOER). Compare KOEO and KOER PID values. Turn ignition off. If difference between PID values is not within 0.15 volt, go to next step. If difference between PID values is within 0.15 volt, go to step  4.
    3. NOTE: Perform KOER Self-Test and repair any DTCs before proceeding with this test.
    WARNING: Fuel system will remain pressurized when engine is not running. To prevent injury or fire, use caution when working on fuel system.
  3. Check Operation Of EGR Valve -  The symptom indicates possible EGR flow at idle with no EGR DTCs output. Possible causes:
    • Damaged EGR vacuum regulator solenoid.
    • EGR valve not fully seating.
    • EGR vacuum regulator solenoid vent restricted.

    Disconnect vacuum hose at EGR valve and plug hose. Turn ignition on, engine off. Access DPFEGR PID with scan tool and record voltage. Start engine. With engine at idle, look at DPFEGR PID voltage reading and compare to engine off reading. An increase in voltage reading at idle indicates that DPFEGR sensor is sensing EGR flow. Turn ignition off. If DPFEGR PID voltage reading was more at idle by a minimum of 0.15 volt than with engine off, DPFEGR PID voltage reading indicates EGR flow at idle. Since vacuum hose to EGR is disconnected and plugged, fault is most likely in EGR valve. Remove and inspect EGR valve for signs of contamination, unusual wear, carbon deposits, binding or other damage. Repair or replace as necessary. After repair, go to step  20. If DPFEGR PID voltage reading was not as specified, a fault in EGR vacuum supply is indicated. Inspect EGR Vacuum Regulator (EGRVR) solenoid vent and vent filter for restrictions. Repair as necessary. If no restrictions are found, replace EGRVR solenoid. After repair, go to step  20.

  4. Check Fuel Pressure -  Install fuel pressure gauge. Start engine. Note fuel pressure. Increase engine speed to 2500 RPM and maintain for one minute. Note and compare fuel pressure. Turn ignition off. If fuel pressure was 55-70 psi (380-482 kPa) and it remained at specification within 5 psi (35 kPa) for 60 seconds, go to next step. If fuel pressure was not as specified, refer to FUEL DELIVERY SYSTEM  testing under SYSTEM TESTS.
  5. Check Injector Driver PIDS INJ1F Through INJ6F -  Turn ignition on, engine off. Access appropriate PID(s) for suspect fuel injector. If PID status is YES, go to next step. If PID status is NO, go to step  9.
  6. Check Resistance Of Fuel Injector(s) & Harness -  Turn ignition off. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector only. See Figure. Measure resistance of INJ circuit between breakout box terminal No. 71 or 97 and suspect fuel injector breakout box terminal. See BREAKOUT BOX INJECTOR TERMINAL IDENTIFICATION  table. If resistance reading is 11-18 ohms, replace PCM. After repair, go to step  20. If resistance reading is not as specified, go to next step.
    BREAKOUT BOX INJECTOR TERMINAL IDENTIFICATION

    Injector Circuit Breakout Box Terminal No. (2.0L) Breakout Box Terminal No. (3.0L)
    INJ1F 70 75
    INJ2F 96 101
    INJ3F 20 74
    INJ4F 95 100
    INJ5F N/A 73
    INJ6F N/A 99
  7. Check Resistance Of Fuel Injector Harness -  Disconnect 2-pin harness connector at suspected fuel injector. Measure resistance of VPWR circuit between breakout box terminal No. 71 or 97 and fuel injector harness connector terminal. Measure resistance of INJ circuit between appropriate breakout box terminal and fuel injector harness connector terminal. See BREAKOUT BOX INJECTOR TERMINAL IDENTIFICATION  table. If each resistance reading is less than 5 ohms, go to next step. If each resistance reading is not as specified, repair open circuit in suspect wire. After repair, go to step  20.
  8. Check Fuel Injector Harness Circuit For Short To Power Or Ground -  Measure resistance between breakout box terminal No. 71 (VPWR) and suspect fuel injector SIG circuit terminal(s). Measure resistance between breakout box terminal No. 103 (PWR GND) and suspect fuel injector SIG circuit breakout box terminal(s). See BREAKOUT BOX INJECTOR TERMINAL IDENTIFICATION  table. If each resistance reading is more than 10,000 ohms, go to next step. If each resistance reading is not as specified, repair short circuit in suspect wire. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  20.
  9. Inspect Fuel Injector Operation -  Remove fuel injector from suspect cylinder. Swap suspect fuel injector with a fuel injector from another cylinder. Start engine. If misfire DTC does not move to cylinder with suspect fuel injector, go to next step. If misfire DTC moves to cylinder with suspect injector, replace fuel injector. After repair, go to step  20.
    10. NOTE: During next step, some vacuum leaks can be heard.
  10. Check Vacuum System -  Inspect all vacuum lines for damage, such as pinched lines, cracks, proper routing and assembly. If vehicle vacuum system is okay, go to next step. If vacuum system is not okay, repair as necessary. After repair, go to step  20.
    11. CAUTION: Remove front under cover if necessary to observe crankshaft pulley.
  11. Check Damper & Pulley Assembly -  Observe crankshaft pulley for wobble. Examine pulse ring fastened to harmonic damper. If no problem is found, go to next step. If crankshaft pulley wobbles or pulse ring is loose or damaged, disconnect battery for 5 minutes to allow PCM to learn new data due to old pulse ring. Replace pulley or damper assembly. After repair, go to step  20.
    12. NOTE: Misfire Monitor can be influenced by Evaporative Emission (EVAP) system. Next five test steps will diagnose EVAP system.
  12. Check Evaporative Emission System -  Check EVAP canister for fuel saturation. If an excess amount of liquid fuel is not present, check fuel tank vent system. Go to next step. If an excess amount of liquid fuel is present in EVAP canister, replace EVAP canister. After repair, go to step  20.
  13. Pressure Test Evaporative Emission System -  Perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST under FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - B2300, B3000, B4000 & TRIBUTE article. If EVAP system is holding pressure, go to next step. If EVAP system is leaking, repair as necessary. After repair, go to step  20.
  14. Check Vacuum In Evaporative Emission System -  Check for blockage/restrictions or cut hoses between engine vacuum port and EVAP canister. Check for blockage in fuel tank vent system. If no fault is indicated, go to next step. If fault is indicated, replace damaged vacuum hoses or remove blockage/restrictions. After repair, go to step  20.
    15. NOTE: EVAP Canister Purge Valve may also be referred to as a Vapor Management Valve.
  15. Check For Evaporative Emission Canister Purge Valve Housing Leaks -  Verify EVAP canister purge valve 2-pin harness connector is securely connected. Install hand vacuum pump to fuel vapor port on EVAP canister purge valve. Apply 16 in. Hg (53 kPa) of vacuum with vacuum pump. If EVAP canister purge solenoid holds vacuum at room temperature, go to next step. If EVAP canister purge solenoid does not hold vacuum, replace EVAP canister purge solenoid. After repair, go to step  20.
  16. Check For Filter Contamination Or Damage On Evaporative Emission Purge Valve -  Remove vacuum line from input port to intake manifold on EVAP canister purge solenoid (control vacuum solenoid part of valve). Install a hand held vacuum pump to open input vacuum port on EVAP canister purge solenoid. Apply 10-15 in. Hg (48-52 kPa) of vacuum to EVAP canister purge solenoid. If EVAP canister purge solenoid valve does not hold vacuum, remove vacuum pump and go to next step. If EVAP canister purge valve holds vacuum or if valve is very slow to release vacuum to atmosphere, service EVAP canister purge solenoid filter. If unable to clean filter or remove blockage, replace EVAP canister purge solenoid. After repair, go to step  20.
    17. NOTE: This step will determine if there are any base engine problems that may have caused misfire DTC or driveability concern.
  17. Check For Base Engine Concerns -  Perform the following tests in order to evaluate base engine integrity.
    • Check PCV system.
    • Check possible leakage points.
    • Perform Engine Compression Test. Refer to MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article.
    • Perform Valve Train Analysis.
    If any service is required, service as necessary. After service, go to step  20. If service is not required, fault that caused misfire DTC is intermittent. Refer to INTERMITTENT  testing under SYSTEM TESTS.
  18. Check/Compare PID Values -  Turn all accessories off (A/C, heater, etc.). Turn ignition on, engine off (KOEO). Access DPFEGR PID with scan tool and record values. Start engine (KOER). Compare KOEO and KOER PID values. Turn ignition off. If difference between PID values are within 0.15 volt, go to step  20. If difference between KOEO and KOER PID values are not within 0.15 volt, disconnect scan tool and go to next step.
  19. Check CMP Sensor Output -  Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) between PCM harness connector and PCM. See Figure. Set multimeter on AC scale (monitor less than 5 volts). Measure voltage between breakout box terminal No. 85 (CMP) and terminals No. 51 and 103 (PWR GND) while running engine at varying RPM. If AC voltage varies more than 0.1 volt, ensure Camshaft Position (CMP) sensor is installed correctly. If CMP sensor is installed correctly, replace PCM. After repair, go to next step. If AC voltage reading does not vary as specified, replace CMP sensor. After repair, go to next step.
  20. Drive Cycle -  Reconnect all disconnected connectors. Clear DTCs from PCM memory using scan tool generic OBD-II function. Perform FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES. Retrieve pending code. If same DTC is present replace PCM. After repair, go to next step. If same DTC is not present, go to next step.
  21. Verify Trouble Shooting Of DTCs Completed -  Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any 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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