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Engine Controls - Self-Diagnostics - Tests: Other Mazda MX-5 NB

Testing & Diagnostics ~3385 words

Condition

DTC is set when input voltage from MAF sensor is less than .86 volt with engine started for 3 seconds. Possible causes are

  1. MAF sensor malfunction.
  2. Open or short circuit between main relay and MAF sensor.
  3. Open or short circuit between Powertrain Control Module (PCM) and MAF sensor.

DTC is set when input voltage from MAF sensor is more than 4.9 volts with engine started for 3 seconds. Possible causes are

  1. MAF sensor malfunction.
  2. Open or short circuit between Powertrain Control Module (PCM) terminal No. 2L and MAF sensor terminal "B".

Barometric pressure variation is less than 1.31 in. Hg (4.5 kPa). Possible causes are

  1. EGR boost sensor malfunction.
  2. EGR boost sensor valve hose loose, plugged or damaged.
  3. EGR boost sensor solenoid valve malfunction.
  4. Open or short circuit between EGR boost sensor and PCM.
  5. Open or short circuit between EGR boost sensor and main relay.
  6. Open or short circuit between EGR boost sensor solenoid valve and PCM.

Input voltage from EGR boost sensor is less than .2 volts. Possible causes are

  1. EGR boost sensor malfunction.
  2. Open or short circuit between EGR boost sensor and PCM.

Input voltage from EGR boost sensor is more than 4.79 volts. Possible causes are

  1. EGR boost sensor malfunction.
  2. Open or short circuit between EGR boost sensor and PCM.

Conditions

DTC is set if input voltage from IAT indicates intake air temperature is 104° F (40° C) greater than engine coolant temperature. Possible causes are

  1. IAT sensor malfunction.
  2. ECT sensor malfunction.
  3. Open or short circuit between IAT sensor and Powertrain Control Module (PCM).
  4. Open or short circuit between ECT sensor and Powertrain Control Module (PCM).

DTC is set if input voltage from IAT is less than .16 volt when engine is started. Possible causes are

  1. IAT sensor malfunction.
  2. Open or short circuit between IAT sensor and Powertrain Control Module (PCM).

DTC is set if input voltage from IAT is more than 4.84 volt when engine is started. Possible causes are

  1. IAT sensor malfunction.
  2. Open or short circuit between IAT sensor and Powertrain Control Module (PCM).

DTC is set if input voltage from ECT sensor is less than .2 volt when ignition is turned on. Possible causes are

  1. ECT sensor malfunction.
  2. Open or short circuit between ECT sensor and Powertrain Control Module (PCM).

DTC is set if input voltage from ECT sensor is more than 4.9 volts when ignition is turned on. Possible causes are

  1. ECT sensor malfunction.
  2. Open circuit between ECT sensor and Powertrain Control Module (PCM).

DTC is set when input voltage from TP sensor is less than one volt (DTC P0122) or greater than 4.8 volts (DTC P0123) when ignition is turned on, or when TP sensor voltage is not within normal range when engine is running (DTC P0123 only). Possible causes are

  1. TP sensor malfunction.
  2. Open or short circuit between Powertrain Control Module (PCM) and TP sensor.
  3. Mass Airflow (MAF) sensor malfunction (DTC P0123 only).

DTC is set when engine coolant temperature has not increased after engine is started and default period of time has passed. Possible causes are

  1. Engine coolant temperature sensor malfunction.
  2. Thermostat malfunction.
  3. Engine cooling fan system malfunction.
  4. Water pump malfunction.
  5. Engine coolant passage clogged or leaks.
  6. Engine coolant level or mixture incorrect.

DTC is set when front oxygen sensor signal fluctuates at intervals of 2.7 (M/T) or 2.9 (A/T) seconds or longer during the following driving conditions

  1. 750-3090 RPM.
  2. Vehicle speed is more than 3.5 MPH (5.6 km/h).
  3. Variation of less than 670 RPM (M/T) or 580 RPM (A/T) for .5 second.
  4. Charging variation of less than 50 percent (M/T) or 16 percent (A/T) for .5 second.
  5. TP sensor input variation of less than .31 volt (M/T) or .16 volt (A/T) for .5 second.

Possible causes are

  1. Front Oxygen Sensor
  2. Oxygen Sensor Harness And/Or Connector
  3. Fuel Injection System Malfunction
  4. Intake System Malfunction
  5. Exhaust System Malfunction.
  6. EVAP System Malfunction.
  7. PCV System Malfunction.
  8. Ignition System Malfunction.
  9. Engine System Sensor Malfunction.
  10. Vacuum Hose Or Wiring Malfunction.

DTC is set when front oxygen sensor signal voltage does not exceed .45 volt after engine is started, or stays less than .45 volt for 52 seconds after engine has reached normal operating temperature, engine speed is 1150 RPM or greater and TP sensor voltage is more than .62 volt. Possible causes are

  1. Front Oxygen Sensor
  2. Front Oxygen Sensor wiring or connections.

DTC is set when rear O2 sensor voltage is more than .45 volt for 6 seconds when vehicle is in deceleration (fuel cut) and engine is at normal operating temperature. Possible cause is short circuit in rear O2 sensor wiring harness.

DTC is set when rear oxygen sensor signal voltage does not exceed .45 volt after engine is started, or stays less than .45 volt for 19 seconds after engine has reached normal operating temperature, TP sensor input is .62 volt and engine speed at 1500 RPM or greater. Possible cause; Rear oxygen sensor.

DTC is set when fuel injection closed loop correction and learning correction are greater than specified value because of system too lean. Deterioration or malfunction of following components and/or systems could contribute to DTC P0171 being set. Possible causes are

  1. Fuel injector malfunction.
  2. Fuel pump malfunction.
  3. Fuel filter clogged.
  4. Fuel lines clogged or leaking.
  5. Pressure regulator malfunction.
  6. Pulsation damper malfunction.
  7. Ignition coil malfunction.
  8. Ignition module malfunction.
  9. Ignition wire malfunction.
  10. Spark plug malfunction.
  11. Intake air system leakage.
  12. Exhaust system leak.
  13. Low compression.
  14. Mass Airflow (MAF) sensor malfunction.
  15. Engine Coolant Temperature (ECT) sensor malfunction.
  16. Throttle Position (TP) sensor malfunction.
  17. PRC solenoid malfunction.
  18. Front oxygen sensor malfunction.
  19. Wiring or connector malfunction.
  20. Vacuum hose leak.

DTC is set when fuel injection closed loop correction and learning correction are greater than specified value because of system rich condition. Deterioration or malfunction of following components and/or systems could contribute to DTC P0172 being set. Possible causes are

  1. Fuel injector malfunction.
  2. Fuel return hose clogged.
  3. Pressure regulator malfunction.
  4. Purge solenoid valve malfunction.
  5. PRC solenoid malfunction.
  6. Mass Airflow (MAF) sensor malfunction.
  7. Engine Coolant Temperature (ECT) sensor malfunction.
  8. Throttle Position (TP) sensor malfunction.
  9. Front oxygen sensor malfunction.
  10. Wiring or connector malfunction.

DTC is set when PCM input signal from Crankshaft Position (CKP) sensor signal is irregular. Deterioration or malfunction of following components and/or systems could contribute to DTC P0300 being set. Possible causes are

  1. Ignition timing out of specification.
  2. Incorrect CKP sensor air gap.
  3. Ignition system malfunction.
  4. CMP sensor malfunction.
  5. Fuel system malfunction.
  6. PRC solenoid malfunction.
  7. Purge solenoid malfunction.
  8. PCV valve malfunction.
  9. Intake air system malfunction.
  10. Insufficient compression.
  11. EGR system malfunction.
  12. Vibration of drive unit.
  13. Excessive load of accessories mounted to engine.
  14. MAF sensor malfunction.
  15. ECT sensor malfunction.
  16. IAT sensor malfunction.
  17. CKP sensor malfunction.
  18. TP sensor malfunction.
  19. Closed throttle position switch malfunction.
  20. Front O2 sensor malfunction.
  21. VSS malfunction.

DTC is set when PCM input signal from Crankshaft Position (CKP) sensor signal is irregular. Deterioration or malfunction of following components and/or systems could contribute to DTC P0301-P0304 being set. Possible causes are

  1. Ignition system malfunction on cylinders No. 1-4.
  2. Ignition timing out of specification.
  3. Incorrect CKP sensor air gap.
  4. Ignition system malfunction.
  5. CMP sensor malfunction.
  6. Fuel system malfunction.
  7. PRC solenoid malfunction.
  8. Purge solenoid malfunction.
  9. PCV valve malfunction.
  10. Intake air system malfunction.
  11. Insufficient compression.
  12. EGR system malfunction.
  13. Vibration of drive unit.
  14. Excessive load of accessories mounted to engine.
  15. MAF sensor malfunction.
  16. ECT sensor malfunction.
  17. IAT sensor malfunction.
  18. CKP sensor malfunction.
  19. TP sensor malfunction.
  20. Front O2 sensor malfunction.
  21. VSS malfunction.

DTC is set when input voltage from knock sensor is less than 1.25 volts or more than 3.75 volts while engine is running. Possible causes are

  1. Knock sensor malfunction.
  2. Improper sensor installation.
  3. Open or short in wiring between PCM and sensor.

DTC is set when there is no NE signal input from Crankshaft Position (CKP) sensor while engine is running. Possible causes are

  1. CKP sensor malfunction.
  2. Incorrect CKP air gap.
  3. Open or short circuit between Powertrain Control Module (PCM) and CKP.
  4. Open or short circuit between main relay and CKP.

DTC is set when there is no NE signal input from Crankshaft Position (CKP) sensor while engine is running. Possible causes are

  1. CKP sensor malfunction.
  2. Incorrect CKP air gap.
  3. Open or short circuit between Powertrain Control Module (PCM) and CKP.
  4. Open or short circuit between main relay and CKP.

DTC is set when the difference in intake manifold pressure between open EGR and closed EGR is too small. Possible causes are

  1. EGR valve malfunction.
  2. EGR boost sensor malfunction.
  3. EGR boost sensor solenoid malfunction.
  4. Clogged EGR system.
  5. TP sensor malfunction.
  6. IAT sensor malfunction.
  7. VSS sensor malfunction.
  8. MAF sensor malfunction.
  9. Open or short circuit in wiring.
  10. Vacuum hoses loose or damaged.

DTC is set when the difference in intake manifold pressure between open EGR and closed EGR is too large. Possible causes are

  1. EGR valve malfunction.
  2. EGR boost sensor malfunction.
  3. MAF sensor malfunction.
  4. TP sensor malfunction.
  5. IAT sensor malfunction.
  6. VSS sensor malfunction.
  7. Open or short circuit in wiring.
  8. Vacuum hoses loose or damaged.

DTC is set when rear oxygen sensor value difference becomes closer to value of front oxygen sensor. Possible causes are

  1. Three way catalytic converter deterioration.
  2. Exhaust system malfunction.
  3. Rear O2 sensor malfunction.
  4. Front O2 sensor malfunction.
  5. MAF sensor malfunction.
  6. TP sensor malfunction.
  7. VSS malfunction.

DTC is set when PCM detects excessive difference in fuel tank pressures measured immediately after purge control is stopped with Canister Drain Cut Valve (CDCV) closed and preset period of time has elapsed. Possible causes are

  1. Purge solenoid malfunction.
  2. CDCV malfunction.
  3. Vent cut valve malfunction.
  4. Loose fuel filler cap.
  5. Charcoal canister malfunction.
  6. Catch tank malfunction.
  7. Rollover valve malfunction.
  8. Cracked fuel tank.
  9. Clogs or leakage in system hoses.
  10. Fuel level sensor malfunction.
  11. Fuel tank pressure sensor malfunction.
  12. ECT sensor malfunction.
  13. IAT sensor malfunction.
  14. TP sensor malfunction.
  15. MAF sensor malfunction.
  16. VSS malfunction.
  17. Open or short in wiring.

DTC is set when purge solenoid valve voltage is too low with valve on or too high with valve off. Possible causes are

  1. Purge solenoid valve malfunction.
  2. Open or short circuit between terminal "A" on purge solenoid valve and terminal "D" on main relay.
  3. Open or short circuit between terminal "B" on purge solenoid valve and terminal No. 3L on Powertrain Control Module (PCM).

DTC is set within 1-3 seconds of start, when engine temperature is below 176°F (80°C) and fuel tank pressure sensor input is less than .2 volt (P0450) or more than 4.8 volts (P0453). Possible causes are

  1. Fuel tank pressure sensor malfunction.
  2. Open or short circuit between terminal "C" on fuel tank pressure sensor and terminal No. 2I on Powertrain Control Module (PCM).
  3. Open or short circuit between terminal "A" on fuel tank pressure sensor and terminal No. 2A on PCM.
  4. Short circuit between terminal "B" on fuel tank pressure sensor and terminal No. 3F on PCM (P0453 only).

DTC is set when PCM detects high pressure (no vacuum) in fuel tank measured immediately after purge control is stopped with Canister Drain Cut Valve (CDCV) closed. Possible causes are

  1. Purge solenoid malfunction.
  2. CDCV malfunction.
  3. Tank Pressure Control Valve (TPCV) malfunction.
  4. Vent cut valve malfunction.
  5. Loose fuel filler cap.
  6. Charcoal canister malfunction.
  7. Catch tank malfunction.
  8. Rollover valve malfunction.
  9. Cracked fuel tank.
  10. Clogs or leakage in system hoses.
  11. Insufficient manifold absolute pressure.
  12. EGR boost sensor malfunction.
  13. Fuel level sensor malfunction.
  14. Fuel tank pressure sensor malfunction.
  15. Engine Coolant Temperature (ECT) sensor malfunction.
  16. Intake Air Temperature (IAT) sensor malfunction.
  17. Throttle Position (TP) sensor malfunction.
  18. Mass Airflow (MAF) sensor malfunction.
  19. Vehicle Speed Sensor (VSS) malfunction.

DTC is set when fuel gauge sending unit operation range is narrow when fuel consumption is more than 8 gallons (16L). Possible causes are

  1. Sending unit malfunction.
  2. Open or short in wiring.
  3. Instrument cluster malfunction.

DTC is set when fuel gauge sending unit voltage is less than .07 volt (P0463) or more than 5.4 volts (P0462) and battery voltage is normal. Possible causes are

  1. Sending unit malfunction.
  2. Open or short in wiring.
  3. Instrument cluster malfunction.

DTC is set when vehicle speed signal is less than 2.3 MPH (3.7KMH) for more than 26 seconds while driving vehicle with engine speed greater than 2000 RPM and charging efficiency is more than 40 percent. Possible causes are

  1. Speedometer sensor malfunction.
  2. Open or short circuit between ignition switch and speedometer sensor.
  3. Open or short circuit between ground and speedometer sensor.
  4. Open or short circuit between VSS and speedometer sensor.
  5. Open or short circuit between VSS and Powertrain Control Module (PCM).

DTC is set when actual engine speed is 100 RPM lower than target speed preset in PCM for more than 14 seconds with brake pedal depressed and steering wheel straight ahead. Possible causes are

  1. Open or short circuit.
  2. Idle Air Control (IAC) valve clogged.
  3. Damaged throttle body.
  4. Air leaks.
  5. PCV valve malfunction.
  6. ECT sensor malfunction.
  7. Purge control solenoid valve malfunction.
  8. Fuel system malfunction.
  9. A/C compressor staying on.
  10. Low engine compression.
  11. EGR valve malfunction.

DTC is set when actual engine speed is 200 RPM higher than target speed preset in PCM for more than 14 seconds with brake depressed and steering wheel straight. Possible causes are

  1. Short circuit in wiring.
  2. Idle Air Control (IAC) valve malfunction.
  3. Vacuum leaks.
  4. Damaged throttle body malfunction.
  5. ECT sensor malfunction.
  6. Throttle cable misadjustment.

DTC is set when vehicle speed is 37 MPH or more, coolant temperature is 140°F (60°C) or more and PCM receives power steering switch signal continuously for more than 60 seconds. Possible causes are

  1. Power Steering Pressure (PSP) switch malfunction.
  2. Open or short circuit between PSP switch terminal and terminal No. 1G on Powertrain Control Module (PCM).
  3. Power steering system malfunction.

DTC is set when PCM has not received brake switch signal when vehicle has accelerated from zero to more than 19 MPH 10 consecutive times. Possible causes are

  1. Brake switch malfunction.
  2. Open or short circuit between brake switch terminal and terminal No. 1F on Powertrain Control Module (PCM).
  3. Open or short in power supply circuit.

DTC is set when PCM has not received clutch switch signal when vehicle has accelerated from zero to more than 19 MPH 10 consecutive times. DTC is also set when clutch switch does not turn off when engine speed is below 400 RPM. Possible causes are

  1. Clutch switch malfunction.
  2. Open or short circuit between clutch switch terminal and terminal No. 3I in Powertrain Control Module (PCM).
  3. PCM malfunction.

DTC is set when PCM has not received clutch switch signal when vehicle has accelerated from zero to more than 19 MPH 10 consecutive times. DTC is also set when clutch switch does not turn off when engine speed is below 400 RPM. Possible causes are

  1. Neutral switch malfunction.
  2. Powertrain Control Module (PCM) malfunction.
  3. Open or short in wiring between neutral switch and PCM.

DTC is set if input voltage from MAF is less than expected for 5 seconds when engine speed is more than 500 RPM and throttle is opened 50 percent or more. Possible causes are

  1. Open or short in wiring.
  2. Mass air flow sensor malfunction.
  3. Blockage in MAF screen.
  4. TP sensor malfunction or mis-adjusted.

DTC is set if input voltage from MAF is more than expected for 5 seconds when engine speed is less than 2000 RPM and ECT is 176°F (80°C) or more. Possible causes are

  1. Open or short in wiring.
  2. Mass air flow sensor malfunction.
  3. Low battery.
  4. MAF damaged.
  5. Air leaks around MAF.

DTC is set if TP sensor position is less than 12 percent when engine coolant is 176°F (80°C) or more and MAF flow is more than 63.2 g/sec. Possible causes are

  1. TP sensor malfunction.
  2. MAF sensor malfunction.
  3. Open or short circuit in wiring.

DTC is set if TP sensor position is more than 50 percent when engine speed is more than 500 RPM and MAF flow is less than 5.3 g/sec. Possible causes are

  1. TP sensor malfunction.
  2. MAF sensor malfunction.
  3. Open or short circuit in wiring.

DTC is set if PCM voltage is less than 5.8 volts when no power is supplied to heater (first 325 seconds after engine start). Possible causes are

  1. Front O2 sensor heater malfunction.
  2. Open or short circuit in wiring.

DTC is set if PCM voltage is more than 11.5 volts when power is supplied to heater. Possible causes are

  1. Front O2 sensor heater malfunction.
  2. Short circuit in wiring.

DTC is set if PCM voltage is less than 5.8 volts when no power is supplied to heater (first 325 seconds after engine start). Possible causes are

  1. Rear O2 sensor heater malfunction.
  2. Open or short circuit in wiring.

DTC is set if PCM voltage is more than 11.5 volts when power is supplied to heater. Possible causes are

  1. Rear O2 sensor heater malfunction.
  2. Short circuit in wiring.

DTC is set when front oxygen sensor signal voltage exceeds .45 volt and remains unchanged for 42 seconds after engine is started and has reached normal operating temperature. Engine speed at 1150 RPM or greater. Possible cause; Front oxygen sensor.

DTC is set when there is no SGC signal input from Camshaft Position (CMP) sensor while engine is running. Possible causes are

  1. CMP sensor malfunction.
  2. Open or short circuit in wiring.

DTC is set when PCM detects open or short circuit in CDCV system with ignition switch on. Possible causes are

  1. CDCV malfunction.
  2. Open or short circuit between terminal "A" on CDCV and main relay.
  3. Open or short circuit between terminal "B" on CDCV and terminal No. 3U on Powertrain Control Module (PCM).

DTC is set when PCM detects fuel tank pressure is low (-1.2 in. Hg) after engine is started in cold condition and vehicle speed is less than 62 MPH. Possible causes are

  1. Purge solenoid malfunction.
  2. Canister Drain Cut Valve (CDCV) malfunction.
  3. Tank Pressure Control Valve (TPCV) malfunction.
  4. Vent cut valve malfunction.
  5. Charcoal canister malfunction.
  6. Two-way check valve clogged.
  7. Clogs or leakage in system hoses.
  8. Fuel tank pressure sensor malfunction.
  9. Engine Coolant Temperature (ECT) sensor malfunction.
  10. Vehicle Speed Sensor (VSS) malfunction.

DTC is set when PCM detects open or short in EGR boost sensor solenoid valve with ignition on. Possible causes are

  1. EGR boost sensor solenoid valve malfunction.
  2. Open or short circuit in wiring.

DTC is set when PCM detects open or short in EGR valve with ignition on. Possible causes are

  1. EGR valve malfunction.
  2. Open or short circuit in wiring.

DTC is set when PCM detects no voltage from IAC when battery voltage is more than 11 volts and IAC actuation time is .37-1.43 volt. DTC will not set during cranking. Possible causes are

  1. IAC valve malfunction.
  2. Open or short circuit in wiring.

DTC is set when Powertrain Control Module (PCM) detects open or short circuit in VRIS solenoid No. 1 system with ignition switch on. Possible causes are

  1. VRIS solenoid valve malfunction.
  2. Open or short circuit between terminal "A" on VRIS solenoid valve and main relay.
  3. Open or short circuit between terminal "B" on VRIS solenoid valve and terminal No. 3Q on Powertrain Control Module (PCM).

DTC is set when Powertrain Control Module (PCM) backup memory voltage is less than 1.4 volt. DTC will not set while cranking. Possible cause; Open or short circuit between positive battery terminal and terminal No. 1A on Powertrain Control Module (PCM).

DTC is set when there is no Transmission Control Module (TCM) to Powertrain Control Module (PCM) communication. Possible causes are

  1. Open or short circuit between TCM and PCM.
  2. Open or short circuit between TCM and power.
  3. Open or short circuit between TCM and ground.

DTCs are set when Powertrain Control Module (PCM) does not read DTCs from output devices. Cause is malfunctioning PCM. Replace PCM and erase any DTCs present. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION - MIATA & MILLENIA article. Retest vehicle.

DTC is set when PCM demands more than 20 amp output from generator, and detects generator output voltage less than 8.5 volts. Possible causes are

  1. Generator malfunction.
  2. Open or short circuit between generator and PCM.

DTC is set when PCM detects battery voltage is less than 8 volts. Possible cause; Open or short circuit between battery and terminal 1H on Powertrain Control Module (PCM).

DTC is set when PCM detects generator output is more than 18 volts or battery voltage is more than 16 volts. Possible causes are

  1. Generator malfunction (overcharge).
  2. PCM malfunction.
  3. Open or short circuit between battery and terminal 1B on Powertrain Control Module (PCM).

DTC is set when generator output is more than 17 volts and battery voltage is less than 11 volts while idling. Possible causes are

  1. Generator malfunction.
  2. Battery malfunction.
  3. Open or short circuit between battery and generator.

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