Symptom Troubleshooting [Engine Control System [Mzr 2.5]]: Other

NO.1 MELTING OF MAIN OR OTHER FUSES [MZR 2.5]

1 MELTING OF MAIN OR OTHER FUSES [TROUBLESHOOTING HINTS] Inspect condition of fuse. Damaged fuse Related wiring harness MAIN MAIN fuse BTN fuse ROOM fuse FAN fuse IG KEY2 fuse Generator BTN BTN fuse ROOM fuse ROOM ROOM fuse DLC-2 FAN FAN fuse Fan control module relay IG KEY2 IG KEY2 fuse Starter relay FUEL PUMP FUEL PUMP fuse Fuel pump unit ST SIG ST SIG fuse Starter relay EGI INJ EGI INJ fuse Fuel injector No.1 Fuel injector No.2 Fuel injector No.3 Fuel injector No.4 PCM ENG+B ENG+B fuse PCM CV solenoid valve PCM PCM fuse PCM ENGINE IG ENGINE IG fuse Ignition coil No.1 Ignition coil No.2 Ignition coil No.3 Ignition coil No.4 PCM Fuel pump relay Diode Fan control module relay HO2S HO2S fuse HO2S (heater) ENGINE ENGINE fuse Variable tumble solenoid valve Variable intake air solenoid valve EGR valve Purge solenoid valve A/F sensor MAF/IAT sensor

Scheme 65

Scheme 65: NO.1 MELTING OF MAIN OR OTHER FUSES [MZR 2.5]

NO.2 MIL ILLUMINATES [MZR 2.5]

2	MIL ILLUMINATES
DESCRIPTION	MIL is illuminated incorrectly.
POSSIBLE CAUSE	The MIL illuminates for emission-related concern (DTC is stored in PCM.) Instrument cluster malfunction NOTE: If the MIL blinks at steady rate, misfire condition could possibly exist.

NOTE
If the MIL blinks at steady rate, misfire condition could possibly exist.

NO.3 WILL NOT CRANK [MZR 2.5]

3 WILL NOT CRANK DESCRIPTION Starter does not work. POSSIBLE CAUSE Open starter circuit between the ignition switch and the starter TR switch malfunction (ATX) TR switch misadjustment (ATX) Starter interlock switch malfunction (MTX) Open or short circuit in wiring harness between keyless control module and TR switch (ATX with advanced keyless entry and push button start system) Open or short circuit in wiring harness between keyless control module and starter interlock switch (MTX with advanced keyless entry and push button start system) Low or dead battery Charging system malfunction Starter malfunction Seized/hydro locked engine, flywheel (MTX) or drive plate (ATX) Immobilizer system and/or related circuit malfunction Immobilizer system operating properly (Key is not registered.) Advanced keyless entry and push button start system malfunction (with advanced keyless entry and push button start system)

Scheme 66

Scheme 66: NO.3 WILL NOT CRANK [MZR 2.5]

NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [MZR 2.5]

4	HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK
DESCRIPTION	Starter cranks engine at normal speed but engine requires excessive cranking time before starting. Battery is in normal condition.
POSSIBLE CAUSE	NOTE: If the ignition is not switched off (to LOCK or ACC) after the engine stalls, and then an engine restart is attempted, the PCM corrects the difference between CKP sensor and CMP sensor signals caused by engine stalling, which may result in more time needed to restart the engine. Vacuum leakage Poor fuel quality Low or dead battery Restriction in intake-air system Charging system malfunction PCM DTC is stored. Cooling system malfunction Ignition coil related wiring harness malfunction Ignition system malfunction Spark plug malfunction CKP sensor and teeth of crankshaft pulley malfunction Improper operation of drive-by-wire control system Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Purge solenoid valve malfunction MAF sensor malfunction Restriction in exhaust system EGR valve malfunction Starting system malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK

DESCRIPTION

Starter cranks engine at normal speed but engine requires excessive cranking time before starting. Battery is in normal condition.

POSSIBLE CAUSE

NOTE: If the ignition is not switched off (to LOCK or ACC) after the engine stalls, and then an engine restart is attempted, the PCM corrects the difference between CKP sensor and CMP sensor signals caused by engine stalling, which may result in more time needed to restart the engine. Vacuum leakage Poor fuel quality Low or dead battery Restriction in intake-air system Charging system malfunction PCM DTC is stored. Cooling system malfunction Ignition coil related wiring harness malfunction Ignition system malfunction Spark plug malfunction CKP sensor and teeth of crankshaft pulley malfunction Improper operation of drive-by-wire control system Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Purge solenoid valve malfunction MAF sensor malfunction Restriction in exhaust system EGR valve malfunction Starting system malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NOTE
If the ignition is not switched off (to LOCK or ACC) after the engine stalls, and then an engine restart is attempted, the PCM corrects the difference between CKP sensor and CMP sensor signals caused by engine stalling, which may result in more time needed to restart the engine. Vacuum leakage Poor fuel quality Low or dead battery Restriction in intake-air system Charging system malfunction PCM DTC is stored. Cooling system malfunction Ignition coil related wiring harness malfunction Ignition system malfunction Spark plug malfunction CKP sensor and teeth of crankshaft pulley malfunction Improper operation of drive-by-wire control system Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Purge solenoid valve malfunction MAF sensor malfunction Restriction in exhaust system EGR valve malfunction Starting system malfunction

NOTE

If the ignition is not switched off (to LOCK or ACC) after the engine stalls, and then an engine restart is attempted, the PCM corrects the difference between CKP sensor and CMP sensor signals caused by engine stalling, which may result in more time needed to restart the engine. Vacuum leakage Poor fuel quality Low or dead battery Restriction in intake-air system Charging system malfunction PCM DTC is stored. Cooling system malfunction Ignition coil related wiring harness malfunction Ignition system malfunction Spark plug malfunction CKP sensor and teeth of crankshaft pulley malfunction Improper operation of drive-by-wire control system Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Purge solenoid valve malfunction MAF sensor malfunction Restriction in exhaust system EGR valve malfunction Starting system malfunction

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.5 ENGINE STALLS-AFTER START/AT IDLE [MZR 2.5]

5	ENGINE STALLS-AFTER START/AT IDLE
DESCRIPTION	Engine stops unexpectedly at idle and/or after start.
POSSIBLE CAUSE	Air cleaner restriction Improper installation of EGR valve Electrical connector disconnected Poor fuel quality Ignition wiring malfunction Air leakage from intake air system Intake air system restriction Throttle valve stacking Vacuum leakage APP sensor or related wiring harness malfunction TP sensor or related wiring harness malfunction PCM continuous memory DTC is stored. CKP sensor or related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Ignition coil or related wiring harness intermittent malfunction Ignition system malfunction Spark plug malfunction Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Improper operation of A/C system Purge solenoid valve malfunction EVAP control system malfunction EGR valve malfunction Improper operation of variable valve timing control system Improper valve timing Low engine compression PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

ENGINE STALLS-AFTER START/AT IDLE

DESCRIPTION

Engine stops unexpectedly at idle and/or after start.

POSSIBLE CAUSE

Air cleaner restriction Improper installation of EGR valve Electrical connector disconnected Poor fuel quality Ignition wiring malfunction Air leakage from intake air system Intake air system restriction Throttle valve stacking Vacuum leakage APP sensor or related wiring harness malfunction TP sensor or related wiring harness malfunction PCM continuous memory DTC is stored. CKP sensor or related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Ignition coil or related wiring harness intermittent malfunction Ignition system malfunction Spark plug malfunction Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Improper operation of A/C system Purge solenoid valve malfunction EVAP control system malfunction EGR valve malfunction Improper operation of variable valve timing control system Improper valve timing Low engine compression PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.6 CRANKS NORMALLY BUT WILL NOT START [MZR 2.5]

6	CRANKS NORMALLY BUT WILL NOT START
DESCRIPTION	Starter cranks engine at normal speed but engine will not run. Refer to symptom troubleshooting " NO.5 ENGINE STALLS-AFTER START/AT IDLE " if this symptom appears after engine stall. Fuel is in tank. Battery is in normal condition.
POSSIBLE CAUSE	Vacuum leakage External fuel shut off or accessory Poor fuel quality Air leakage from intake air system Intake air system restriction Proper sealing of intake manifold and components attached to intake manifold: such as EGR valve Ignition wiring malfunction Electrical connector disconnection Fuse malfunction Throttle valve stacking APP sensor and related wiring harness malfunction TP sensor and related wiring harness malfunction PCM continuous memory DTC is stored. Improper operation of drive-by-wire control system CKP sensor and related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Ignition coil and related wiring harness malfunction Spark plug malfunction Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Purge solenoid valve malfunction EVAP control system malfunction EGR valve malfunction Improper operation of variable valve timing control system Low engine compression Improper valve timing WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

CRANKS NORMALLY BUT WILL NOT START

DESCRIPTION

Starter cranks engine at normal speed but engine will not run. Refer to symptom troubleshooting " NO.5 ENGINE STALLS-AFTER START/AT IDLE " if this symptom appears after engine stall. Fuel is in tank. Battery is in normal condition.

POSSIBLE CAUSE

Vacuum leakage External fuel shut off or accessory Poor fuel quality Air leakage from intake air system Intake air system restriction Proper sealing of intake manifold and components attached to intake manifold: such as EGR valve Ignition wiring malfunction Electrical connector disconnection Fuse malfunction Throttle valve stacking APP sensor and related wiring harness malfunction TP sensor and related wiring harness malfunction PCM continuous memory DTC is stored. Improper operation of drive-by-wire control system CKP sensor and related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Ignition coil and related wiring harness malfunction Spark plug malfunction Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Purge solenoid valve malfunction EVAP control system malfunction EGR valve malfunction Improper operation of variable valve timing control system Low engine compression Improper valve timing WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.7 SLOW RETURN TO IDLE [MZR 2.5]

7	SLOW RETURN TO IDLE
DESCRIPTION	Engine takes more time than normal to return to idle speed.
POSSIBLE CAUSE	PCM DTC is stored. Erratic signal from PSP switch ECT sensor malfunction Thermostat is stuck open. Throttle body malfunction Air leakage from intake air system

NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [MZR 2.5]

8	ENGINE RUNS ROUGH/ROLLING IDLE
DESCRIPTION	Engine speed fluctuates between specified idle speed and lower speed and engine shakes excessively. Idle speed is too slow and engine shakes excessively.
POSSIBLE CAUSE	Idle learning of drive-by-wire control system is not completed. Electrical connector disconnection External fuel shut off or accessory Poor fuel quality Fuse malfunction Ignition wiring malfunction Air leakage from intake air system Vacuum leakage PCM ground circuit (1E, 1F, 1G, 1BE, or 1BF) malfunction Improper installation of EGR valve PCM DTC is stored. Engine overheating MAF sensor and related wiring harness malfunction Erratic signal from PSP switch Improper operation of A/C system CKP sensor and teeth of crankshaft pulley malfunction Ignition system malfunction Ignition coil and related wiring harness malfunction Spark plug malfunction Improper operation of drive-by-wire control system Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Purge solenoid valve malfunction EVAP control system malfunction Exhaust system part malfunction CMP sensor and teeth of camshaft malfunction EGR valve malfunction Improper operation of variable valve timing control system Low engine compression PCV valve malfunction Improper valve timing WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

ENGINE RUNS ROUGH/ROLLING IDLE

DESCRIPTION

Engine speed fluctuates between specified idle speed and lower speed and engine shakes excessively. Idle speed is too slow and engine shakes excessively.

POSSIBLE CAUSE

Idle learning of drive-by-wire control system is not completed. Electrical connector disconnection External fuel shut off or accessory Poor fuel quality Fuse malfunction Ignition wiring malfunction Air leakage from intake air system Vacuum leakage PCM ground circuit (1E, 1F, 1G, 1BE, or 1BF) malfunction Improper installation of EGR valve PCM DTC is stored. Engine overheating MAF sensor and related wiring harness malfunction Erratic signal from PSP switch Improper operation of A/C system CKP sensor and teeth of crankshaft pulley malfunction Ignition system malfunction Ignition coil and related wiring harness malfunction Spark plug malfunction Improper operation of drive-by-wire control system Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Purge solenoid valve malfunction EVAP control system malfunction Exhaust system part malfunction CMP sensor and teeth of camshaft malfunction EGR valve malfunction Improper operation of variable valve timing control system Low engine compression PCV valve malfunction Improper valve timing WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.9 FAST IDLE/RUNS ON [MZR 2.5]

9	FAST IDLE/RUNS ON
DESCRIPTION	Engine speed continues at fast idle after warm-up. Engine runs after ignition is off.
POSSIBLE CAUSE	Cooling fan system malfunction ECT sensor malfunction Improper load signal input Refrigerant pressure sensor malfunction Evaporator temperature sensor malfunction Climate control unit malfunction Communication error between climate control unit and instrument cluster Communication error between instrument cluster and PCM Erratic signal from PSP switch CPP switch malfunction (MTX) Neutral switch malfunction (MTX) TR switch malfunction (ATX) Communication error between TCM and PCM (ATX) Air leakage from intake air system Improper operation of drive-by-wire control system APP sensor malfunction

FAST IDLE/RUNS ON

DESCRIPTION

Engine speed continues at fast idle after warm-up. Engine runs after ignition is off.

POSSIBLE CAUSE

Cooling fan system malfunction ECT sensor malfunction Improper load signal input Refrigerant pressure sensor malfunction Evaporator temperature sensor malfunction Climate control unit malfunction Communication error between climate control unit and instrument cluster Communication error between instrument cluster and PCM Erratic signal from PSP switch CPP switch malfunction (MTX) Neutral switch malfunction (MTX) TR switch malfunction (ATX) Communication error between TCM and PCM (ATX) Air leakage from intake air system Improper operation of drive-by-wire control system APP sensor malfunction

NO.10 LOW IDLE/STALLS DURING DECELERATION [MZR 2.5]

10	LOW IDLE/STALLS DURING DECELERATION
DESCRIPTION	Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE	ECT sensor malfunction Improper operation of magnetic clutch Vacuum leakage Air leakage from intake air system Engine mount looseness PCM DTC is stored. Improper operation of drive-by-wire control system Improper operation of EVAP control system Erratic signal to PCM APP sensor malfunction TP sensor malfunction MAF sensor malfunction VSS malfunction Improper load signal input Refrigerant pressure sensor malfunction Evaporator temperature sensor malfunction Climate control unit malfunction Communication error between climate control unit and instrument cluster Communication error between instrument cluster and PCM CPP switch malfunction (MTX) Neutral switch malfunction (MTX) TR switch malfunction (ATX) Communication error between TCM and PCM (ATX)

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION

Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.

POSSIBLE CAUSE

ECT sensor malfunction Improper operation of magnetic clutch Vacuum leakage Air leakage from intake air system Engine mount looseness PCM DTC is stored. Improper operation of drive-by-wire control system Improper operation of EVAP control system Erratic signal to PCM APP sensor malfunction TP sensor malfunction MAF sensor malfunction VSS malfunction Improper load signal input Refrigerant pressure sensor malfunction Evaporator temperature sensor malfunction Climate control unit malfunction Communication error between climate control unit and instrument cluster Communication error between instrument cluster and PCM CPP switch malfunction (MTX) Neutral switch malfunction (MTX) TR switch malfunction (ATX) Communication error between TCM and PCM (ATX)

NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [MZR 2.5]

11	ENGINE STALLS/QUITS-ACCELERATION/CRUISE ENGINE RUNS ROUGH-ACCELERATION/CRUISE MISSES-ACCELERATION/CRUISE BUCK/JERK-ACCELERATION/CRUISE/DECELERATION HESITATION/STUMBLE-ACCELERATION SURGES-ACCELERATION/CRUISE
DESCRIPTION	Engine stops unexpectedly at beginning of acceleration or during acceleration. Engine stops unexpectedly while cruising. Engine speed fluctuates during acceleration or cruising. Engine misses during acceleration or cruising. Vehicle bucks/jerks during acceleration, cruising, or deceleration. Momentary pause at beginning of acceleration or during acceleration. Momentary minor irregularity in engine output.
POSSIBLE CAUSE	Drive-by-wire control system operates with brake override system. Air cleaner restriction Clutch slippage (MTX) Electrical connector disconnection Poor fuel quality Ignition wiring malfunction Air leakage from intake air system Intake air system restriction Improper installation of EGR valve Improper operation of drive-by-wire control system Vacuum leakage Engine mount installation looseness PCM DTC is stored. Engine overheating Erratic signal to PCM APP sensor or related wiring harness malfunction TP sensor or related wiring harness malfunction MAP sensor or related wiring harness malfunction BARO sensor or related wiring harness malfunction CKP sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction Battery power supply circuit malfunction VSS or related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Spark plug malfunction Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Improper operation of A/C control system Improper operation of cruise control system A/F sensor malfunction Fuel shut-off valve malfunction Purge solenoid valve malfunction EVAP control system malfunction CMP sensor and teeth of camshaft malfunction Improper operation of variable valve timing control system Improper operation of EGR valve Low engine compression Improper valve timing Check valve (two-way) malfunction EGR valve mechanical stack ATX internal malfunction (ATX) PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

ENGINE STALLS/QUITS-ACCELERATION/CRUISE ENGINE RUNS ROUGH-ACCELERATION/CRUISE MISSES-ACCELERATION/CRUISE BUCK/JERK-ACCELERATION/CRUISE/DECELERATION HESITATION/STUMBLE-ACCELERATION SURGES-ACCELERATION/CRUISE

DESCRIPTION

Engine stops unexpectedly at beginning of acceleration or during acceleration. Engine stops unexpectedly while cruising. Engine speed fluctuates during acceleration or cruising. Engine misses during acceleration or cruising. Vehicle bucks/jerks during acceleration, cruising, or deceleration. Momentary pause at beginning of acceleration or during acceleration. Momentary minor irregularity in engine output.

POSSIBLE CAUSE

Drive-by-wire control system operates with brake override system. Air cleaner restriction Clutch slippage (MTX) Electrical connector disconnection Poor fuel quality Ignition wiring malfunction Air leakage from intake air system Intake air system restriction Improper installation of EGR valve Improper operation of drive-by-wire control system Vacuum leakage Engine mount installation looseness PCM DTC is stored. Engine overheating Erratic signal to PCM APP sensor or related wiring harness malfunction TP sensor or related wiring harness malfunction MAP sensor or related wiring harness malfunction BARO sensor or related wiring harness malfunction CKP sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction Battery power supply circuit malfunction VSS or related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Spark plug malfunction Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Improper operation of A/C control system Improper operation of cruise control system A/F sensor malfunction Fuel shut-off valve malfunction Purge solenoid valve malfunction EVAP control system malfunction CMP sensor and teeth of camshaft malfunction Improper operation of variable valve timing control system Improper operation of EGR valve Low engine compression Improper valve timing Check valve (two-way) malfunction EGR valve mechanical stack ATX internal malfunction (ATX) PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [MZR 2.5]

12	LACK/LOSS OF POWER-ACCELERATION/CRUISE
DESCRIPTION	Performance is poor under load. (e.g. power down when climbing hills)
POSSIBLE CAUSE	Drive-by-wire control system operates with brake override system. Poor fuel quality Air leakage from intake air system Intake air temperature too hot Intake air system restriction Improper installation of EGR valve Vacuum leakage Clutch slippage (MTX) PCM DTC is stored. Engine overheating Erratic signal to PCM APP sensor or related wiring harness malfunction TP sensor or related wiring harness malfunction CKP sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction IAT sensor or related wiring harness malfunction Battery power supply circuit malfunction VSS or related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Spark plug malfunction Ignition coil malfunction Fuel injector malfunction Fuel leakage from fuel injector Fuel injector is clogging. Throttle valve restriction or clogged Improper operation of drive-by-wire control system Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Improper operation of variable tumble control Improper operation of variable intake air control Improper operation of A/C system Purge solenoid valve malfunction EVAP control system malfunction CMP sensor and teeth of camshaft malfunction Improper operation of EGR valve Improper operation of variable valve timing control system Low engine compression Improper valve timing PCV valve malfunction Brake dragging ATX malfunction (ATX) WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

LACK/LOSS OF POWER-ACCELERATION/CRUISE

DESCRIPTION

Performance is poor under load. (e.g. power down when climbing hills)

POSSIBLE CAUSE

Drive-by-wire control system operates with brake override system. Poor fuel quality Air leakage from intake air system Intake air temperature too hot Intake air system restriction Improper installation of EGR valve Vacuum leakage Clutch slippage (MTX) PCM DTC is stored. Engine overheating Erratic signal to PCM APP sensor or related wiring harness malfunction TP sensor or related wiring harness malfunction CKP sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction IAT sensor or related wiring harness malfunction Battery power supply circuit malfunction VSS or related wiring harness malfunction CKP sensor and teeth of crankshaft pulley malfunction Spark plug malfunction Ignition coil malfunction Fuel injector malfunction Fuel leakage from fuel injector Fuel injector is clogging. Throttle valve restriction or clogged Improper operation of drive-by-wire control system Exhaust system part malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Improper operation of variable tumble control Improper operation of variable intake air control Improper operation of A/C system Purge solenoid valve malfunction EVAP control system malfunction CMP sensor and teeth of camshaft malfunction Improper operation of EGR valve Improper operation of variable valve timing control system Low engine compression Improper valve timing PCV valve malfunction Brake dragging ATX malfunction (ATX) WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZR 2.5]

13	KNOCKING/PINGING-ACCELERATION/CRUISE
DESCRIPTION	Sound is produced when air/fuel mixture is ignited by something other than spark plug. (e.g. hot spot in combustion chamber)
POSSIBLE CAUSE	Engine overheating due to cooling system malfunction Erratic signal to PCM ECT sensor or related wiring harness malfunction IAT sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction PCM DTC is stored. CMP signal malfunction Loose installation CMP sensor and/or damaged pulse wheel CKP signal malfunction Loose installation CKP sensor and/or pulse wheel Low engine compression Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction KS malfunction Improper valve timing Poor fuel quality (i.e. Fuel RON is not specified, excessive cleaning agents added in fuel.) WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

KNOCKING/PINGING-ACCELERATION/CRUISE

DESCRIPTION

Sound is produced when air/fuel mixture is ignited by something other than spark plug. (e.g. hot spot in combustion chamber)

POSSIBLE CAUSE

Engine overheating due to cooling system malfunction Erratic signal to PCM ECT sensor or related wiring harness malfunction IAT sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction PCM DTC is stored. CMP signal malfunction Loose installation CMP sensor and/or damaged pulse wheel CKP signal malfunction Loose installation CKP sensor and/or pulse wheel Low engine compression Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction KS malfunction Improper valve timing Poor fuel quality (i.e. Fuel RON is not specified, excessive cleaning agents added in fuel.) WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.14 POOR FUEL ECONOMY [MZR 2.5]

14	POOR FUEL ECONOMY
DESCRIPTION	Fuel economy is unsatisfactory.
POSSIBLE CAUSE	Contaminated air cleaner element Improper ATF level (ATX) Brake dragging Clutch slippage (MTX) Low tire pressure Improper coolant level Poor fuel quality PCM DTC is stored. Engine cooling system malfunction Improper operation of cooling fan control system Ignition system malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Improper operation of variable tumble control Improper operation of variable valve timing control system Improper operation of variable valve intake air control Exhaust system clogging Contaminated MAF sensor Low engine compression Improper valve timing PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

POOR FUEL ECONOMY

DESCRIPTION

Fuel economy is unsatisfactory.

POSSIBLE CAUSE

Contaminated air cleaner element Improper ATF level (ATX) Brake dragging Clutch slippage (MTX) Low tire pressure Improper coolant level Poor fuel quality PCM DTC is stored. Engine cooling system malfunction Improper operation of cooling fan control system Ignition system malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Improper operation of variable tumble control Improper operation of variable valve timing control system Improper operation of variable valve intake air control Exhaust system clogging Contaminated MAF sensor Low engine compression Improper valve timing PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.15 EMISSION COMPLIANCE [MZR 2.5]

15	EMISSION COMPLIANCE
DESCRIPTION	Fails emissions test.
POSSIBLE CAUSE	Electrical connector disconnection Intake air system and air cleaner element malfunction Vacuum lines leakage or blockage PCM DTC is stored. Cooling system malfunction Fuel-filler cap malfunction A/F sensor malfunction Ignition system improper operation Spark plug malfunction Ignition coil malfunction Ignition coil related wiring harness malfunction Erratic or no signal from CMP sensor Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Charcoal canister malfunction Exhaust system clogging TWC malfunction EGR system malfunction Base engine malfunction Improper engine compression Improper valve timing PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

EMISSION COMPLIANCE

DESCRIPTION

Fails emissions test.

POSSIBLE CAUSE

Electrical connector disconnection Intake air system and air cleaner element malfunction Vacuum lines leakage or blockage PCM DTC is stored. Cooling system malfunction Fuel-filler cap malfunction A/F sensor malfunction Ignition system improper operation Spark plug malfunction Ignition coil malfunction Ignition coil related wiring harness malfunction Erratic or no signal from CMP sensor Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Charcoal canister malfunction Exhaust system clogging TWC malfunction EGR system malfunction Base engine malfunction Improper engine compression Improper valve timing PCV valve malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.16 HIGH OIL CONSUMPTION/LEAKAGE [MZR 2.5]

16	HIGH OIL CONSUMPTION/LEAKAGE
DESCRIPTION	Oil consumption is excessive.
POSSIBLE CAUSE	PCV valve malfunction Improper dipstick Improper engine oil viscosity Engine internal parts malfunction

NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 2.5]

17	COOLING SYSTEM CONCERNS-OVERHEATING
DESCRIPTION	Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	Radiator hoses damage Coolant leakage Leakage around heater unit Leakage at coolant hoses and/or radiator Improper coolant level Fans reverse rotation Fuse malfunction Coolant overflow system malfunction Poor radiator condition Improper or damaged radiator cap Improper water/anti-freeze mixture PCM DTC is stored. Improper operation of A/C system (always on) Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.) Instrument cluster malfunction (Does not receive A/C request signal from climate control unit or transmit it to PCM.) Communication error between PCM and instrument cluster Communication error between instrument cluster and climate control unit (Full-auto air conditioner) Short to ground circuit between instrument cluster terminal 1A and climate control unit terminal 1L (Manual air conditioner) Improper operation of cooling fan control system Improper tension of drive belt Improper indication of water temperature gauge ECT sensor malfunction Instrument cluster (water temperature gauge) malfunction Thermostat malfunction

COOLING SYSTEM CONCERNS-OVERHEATING

DESCRIPTION

Engine runs at higher than normal temperature/overheats.

POSSIBLE CAUSE

Radiator hoses damage Coolant leakage Leakage around heater unit Leakage at coolant hoses and/or radiator Improper coolant level Fans reverse rotation Fuse malfunction Coolant overflow system malfunction Poor radiator condition Improper or damaged radiator cap Improper water/anti-freeze mixture PCM DTC is stored. Improper operation of A/C system (always on) Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.) Instrument cluster malfunction (Does not receive A/C request signal from climate control unit or transmit it to PCM.) Communication error between PCM and instrument cluster Communication error between instrument cluster and climate control unit (Full-auto air conditioner) Short to ground circuit between instrument cluster terminal 1A and climate control unit terminal 1L (Manual air conditioner) Improper operation of cooling fan control system Improper tension of drive belt Improper indication of water temperature gauge ECT sensor malfunction Instrument cluster (water temperature gauge) malfunction Thermostat malfunction

NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZR 2.5]

18	COOLING SYSTEM CONCERNS-RUNS COLD
DESCRIPTION	Engine takes excessive time to reach normal operating temperature.
POSSIBLE CAUSE	A/C and heater system malfunction Thermostat malfunction Cooling fan system malfunction Improper indication of water temperature gauge ECT sensor malfunction Instrument cluster (water temperature gauge) malfunction

NO.19 EXHAUST SMOKE [MZR 2.5]

19	EXHAUST SMOKE
DESCRIPTION	Blue, black, or white smoke from exhaust system.
POSSIBLE CAUSE	Blue smoke (Burning oil): PCV valve malfunction Engine internal oil leakage White smoke (Water in combustion): Cooling system malfunction (coolant loss) Engine internal coolant leakage Black smoke (Rich fuel mixture): Air cleaner restriction Intake air system is collapsed or restricted. Erratic signal to PCM APP sensor or related wiring harness malfunction ECT sensor or related wiring harness malfunction IAT sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction MAP sensor or related wiring harness malfunction A/F sensor or related wiring harness malfunction HO2S or related wiring harness malfunction TP sensor or related wiring harness malfunction VSS or related wiring harness malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Ignition system malfunction CMP sensor malfunction Improper engine compression Improper fuel injection timing and/or amount WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

EXHAUST SMOKE

DESCRIPTION

Blue, black, or white smoke from exhaust system.

POSSIBLE CAUSE

Blue smoke (Burning oil): PCV valve malfunction Engine internal oil leakage White smoke (Water in combustion): Cooling system malfunction (coolant loss) Engine internal coolant leakage Black smoke (Rich fuel mixture): Air cleaner restriction Intake air system is collapsed or restricted. Erratic signal to PCM APP sensor or related wiring harness malfunction ECT sensor or related wiring harness malfunction IAT sensor or related wiring harness malfunction MAF sensor or related wiring harness malfunction MAP sensor or related wiring harness malfunction A/F sensor or related wiring harness malfunction HO2S or related wiring harness malfunction TP sensor or related wiring harness malfunction VSS or related wiring harness malfunction Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Ignition system malfunction CMP sensor malfunction Improper engine compression Improper fuel injection timing and/or amount WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.20 FUEL ODOR (IN ENGINE COMPARTMENT) [MZR 2.5]

20	FUEL ODOR (IN ENGINE COMPARTMENT)
DESCRIPTION	Gasoline fuel smell or visible leakage.
POSSIBLE CAUSE	Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Fuel tank vent system blockage Purge solenoid valve malfunction PCM DTC is stored. Charcoal canister malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

FUEL ODOR (IN ENGINE COMPARTMENT)

DESCRIPTION

Gasoline fuel smell or visible leakage.

POSSIBLE CAUSE

Excessive or insufficient fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Fuel leakage from fuel system Fuel injector malfunction Fuel tank vent system blockage Purge solenoid valve malfunction PCM DTC is stored. Charcoal canister malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZR 2.5]

23	A/C DOES NOT WORK SUFFICIENTLY
DESCRIPTION	A/C compressor magnetic clutch does not engage when A/C is turned on.
POSSIBLE CAUSE	PCM or climate control unit DTC is stored. Refrigerant pressure sensor malfunction Improper refrigerant charging amount Seized A/C compressor Evaporator temperature sensor malfunction Open or short circuit in wiring harness between evaporator temperature sensor and climate control unit Instrument cluster malfunction (Does not receive A/C request signal from climate control unit or transmit it to PCM.) Information display malfunction Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.) Open or short circuit in wiring harness between climate control unit terminal 1L and instrument cluster terminal 1A (Manual air conditioner) Magnetic clutch malfunction Open circuit in wiring harness between magnetic clutch terminal A and body ground A/C relay malfunction Open circuit in wiring harness between A/C relay and PCM terminal 1I Open circuit in wiring harness between ignition switch (IG2) 1 /IG2 relay 2 and A/C relay Open circuit in wiring harness between battery positive terminal and A/C relay Open circuit in wiring harness between A/C relay and magnetic clutch

A/C DOES NOT WORK SUFFICIENTLY

DESCRIPTION

A/C compressor magnetic clutch does not engage when A/C is turned on.

POSSIBLE CAUSE

PCM or climate control unit DTC is stored. Refrigerant pressure sensor malfunction Improper refrigerant charging amount Seized A/C compressor Evaporator temperature sensor malfunction Open or short circuit in wiring harness between evaporator temperature sensor and climate control unit Instrument cluster malfunction (Does not receive A/C request signal from climate control unit or transmit it to PCM.) Information display malfunction Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.) Open or short circuit in wiring harness between climate control unit terminal 1L and instrument cluster terminal 1A (Manual air conditioner) Magnetic clutch malfunction Open circuit in wiring harness between magnetic clutch terminal A and body ground A/C relay malfunction Open circuit in wiring harness between A/C relay and PCM terminal 1I Open circuit in wiring harness between ignition switch (IG2) *1 /IG2 relay *2 and A/C relay Open circuit in wiring harness between battery positive terminal and A/C relay Open circuit in wiring harness between A/C relay and magnetic clutch

NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR 2.5]

24	A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION	A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE	PCM or climate control unit DTC is stored. Short to power supply in wiring harness between A/C relay and magnetic clutch Magnetic clutch engagement is stuck. A/C relay malfunction Short to ground in wiring harness between A/C relay and PCM Communication error between PCM and instrument cluster Communication error between climate control unit and instrument cluster (Full-auto air conditioner) Short to ground in wiring harness between climate control unit terminal 1L and instrument cluster terminal 1A (Manual air conditioner) Climate control unit malfunction

A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY

DESCRIPTION

A/C compressor magnetic clutch does not disengage.

POSSIBLE CAUSE

PCM or climate control unit DTC is stored. Short to power supply in wiring harness between A/C relay and magnetic clutch Magnetic clutch engagement is stuck. A/C relay malfunction Short to ground in wiring harness between A/C relay and PCM Communication error between PCM and instrument cluster Communication error between climate control unit and instrument cluster (Full-auto air conditioner) Short to ground in wiring harness between climate control unit terminal 1L and instrument cluster terminal 1A (Manual air conditioner) Climate control unit malfunction

NO.25 A/C IS NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS [MZR 2.5]

25	A/C IS NOT CUT OFF UNDER WOT CONDITIONS
DESCRIPTION	A/C compressor magnetic clutch does not disengage under WOT.
POSSIBLE CAUSE	APP sensor malfunction Loosely installed APP sensor

NO.26 EXHAUST SULPHUR SMELL [MZR 2.5]

26	EXHAUST SULPHUR SMELL
DESCRIPTION	Rotten egg smell (sulphur) from exhaust.
POSSIBLE CAUSE	Electrical connectors are disconnected or connected poorly. Poor fuel quality Vacuum lines are disconnected or connected improperly. PCM DTC is stored. Improper fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Charcoal canister malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

EXHAUST SULPHUR SMELL

DESCRIPTION

Rotten egg smell (sulphur) from exhaust.

POSSIBLE CAUSE

Electrical connectors are disconnected or connected poorly. Poor fuel quality Vacuum lines are disconnected or connected improperly. PCM DTC is stored. Improper fuel pressure Fuel pump relay or fuel pump circuit malfunction Restriction in fuel line Pressure regulator malfunction (built-into fuel pump unit) Fuel pump malfunction Charcoal canister malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.28 FUEL FILLING SHUT OFF CONCERNS [MZR 2.5]

28	FUEL FILLING SHUT OFF CONCERNS
DESCRIPTION	Fuel does not shut off properly.
POSSIBLE CAUSE	Clogged EVAP pipes Nonreturn valve malfunction Fuel shut-off valve malfunction Fuel nozzle malfunction Fuel nozzle is not inserted correctly. PCM DTC is stored. WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

FUEL FILLING SHUT OFF CONCERNS

DESCRIPTION

Fuel does not shut off properly.

POSSIBLE CAUSE

Clogged EVAP pipes Nonreturn valve malfunction Fuel shut-off valve malfunction Fuel nozzle malfunction Fuel nozzle is not inserted correctly. PCM DTC is stored. WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

WARNING
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .)

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NO.29 SPARK PLUG CONDITION [MZR 2.5]

SPARK PLUG CONDITION

DESCRIPTION

Incorrect spark plug condition.

POSSIBLE CAUSE

NOTE: Inspecting the spark plug conditions can determine whether a problem is related to a specific cylinder or possibly all cylinders. Wet/carbon stuck on specific plug: Spark-Weak, not visible Air/fuel mixture-Excessive fuel injection volume Compression-No compression, low compression Malfunction spark plug Grayish white with specific plug: Air/fuel mixture-Insufficient fuel injection volume Malfunction spark plug Wet/carbon is stuck on all plugs: Spark-Spark weak Air/fuel mixture-Too rich, excessive fuel line pressure Erratic signal to PCM ECT sensor or related circuit malfunction MAF sensor or related circuit malfunction A/F sensor or related circuit malfunction HO2S or related circuit malfunction Compression-Low compression Clogging in intake/exhaust system Grayish white with all plugs: Air/fuel mixture-Too lean, insufficient fuel line pressure Erratic signal to PCM ECT sensor or related circuit malfunction MAF sensor or related circuit malfunction A/F sensor or related circuit malfunction HO2S or related circuit malfunction WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.5] .) (See AFTER SERVICE PRECAUTION [MZR 2.5] .) CAUTION: Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

NOTE
Inspecting the spark plug conditions can determine whether a problem is related to a specific cylinder or possibly all cylinders.

WARNING

CAUTION
Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

Water Sprinkling Method

If malfunction occurs only under high humidity or rainy/snowy weather, perform the following steps

CAUTION

Indirectly change the temperature and humidity by spraying water onto the front of the radiator. If a vehicle is subject to water leakage, the leakage may damage the control module. When testing a vehicle with a water leakage problem, special caution must be used.

Scheme 67

Connect the M-MDS to the DLC-2 if you are inspecting sensors or switches.
Switch the ignition to ON (engine off). NOTE: If the engine starts and runs, perform the following steps at idle.
Access PIDs for sensor or switch if you are inspecting sensors or switches.
If you are inspecting the switch, turn it on manually.
Spray water onto the vehicle or run it through a car wash. If PID value is unstable or malfunction occurs, repair or replace part if necessary.

Finding irregular signals

While referring to «ON-BOARD DIAGNOSTIC TEST [MZR 2.5]»(ref-581633-S34331335932013101400000) , use the PID/DATA monitor and record function to inspect the input signal system relating to the problem.

Start the engine and idle the vehicle. You can assume that any signals that are out of specification by a wide margin are irregular.
When recreating the problem, any sudden change in monitor input signals that is not intentionally created by the driver can be determined as irregular.

Locating the source of unusual signals

CAUTION

Compare the M-MDS monitor voltage with the measurement voltage using the digital measurement system function. If you use another tester, misreading may occur. When measuring voltage, attach the tester ground to the ground of the PCM that is being tested, or to the engine itself. If this is not performed, the measured voltage and actual voltage may differ. After connecting the pin to a waterproof coupler, confirming continuity and measuring the voltage, inspect the waterproof connector for cracks. If there are any, use sealant to fix them. Failure to do this may result in deterioration of the wiring harness or terminal from water damage, leading to problems with the vehicle.

Scheme 68

Scheme 68: Thermistor type (IAT sensor and ECT sensor)

Cooling fans do not operate

Inspect for followings: Open circuit between fan control module relay and battery positive terminal Open circuit between fan control module relay and BCM Open circuit between fan control module relay and fan control module Open circuit between fan control module and ground Poor connection of the fan control module connector Fan control module relay malfunction (See «RELAY INSPECTION»(ref-581640-S26749992412013101400000) .) If there is no malfunction, replace the cooling fan component. (See «COOLING FAN MOTOR REMOVAL/INSTALLATION [MZR 2.5]»(ref-581646-S06325450512013101400000) .)

Cooling fan motor No.1 does not operate

Inspect for followings: Open or short to ground circuit between the fan control module and cooling fan motor No.1 Poor connection of the fan control module connector or cooling fan motor No.1 connector If there is no malfunction, replace the cooling fan component. (See «COOLING FAN MOTOR REMOVAL/INSTALLATION [MZR 2.5]»(ref-581646-S06325450512013101400000) .)

Cooling fan motor No.2 does not operate

Inspect for followings: Open or short to ground circuit between the fan control module and the cooling fan motor No.2 Poor connection of the fan control module connector or the cooling fan motor No.1 connector If there is no malfunction, replace the cooling fan component. (See «COOLING FAN MOTOR REMOVAL/INSTALLATION [MZR 2.5]»(ref-581646-S06325450512013101400000) .)

When idling cannot be continued

Remove the OCV and verify that the spool valve is at maximum retard position.
Connect the OCV.
Switch the ignition to ON.
Verify that the spool valve is at maximum retard position. If the spool valve is stuck in the advance direction, inspect for the following: Short circuit in wiring harnesses or connectors between OCV and PCM
Inspect the variable valve timing actuator. (See «VARIABLE VALVE TIMING ACTUATOR INSPECTION [MZR 2.5]»(ref-581643-S40907724652013101400000) .)

When idling can be continued

Disconnect OCV connector.
Warm up the engine and idle it.
Apply battery voltage to the OCV and verify that the engine idles roughly or stalls. If the engine idles roughly or stalls, inspect the timing chain component (valve timing deviation). If the engine does not idle roughly or stalls, go to the next step.
Remove the OCV and perform spool valve operation inspection. (See «OIL CONTROL VALVE (OCV) INSPECTION [MZR 2.5]»(ref-581643-S00038202252013101400000) .) If not as specified, inspect the following: OCV (See «OIL CONTROL VALVE (OCV) INSPECTION [MZR 2.5]»(ref-581643-S00038202252013101400000) .) Harnesses and connectors between OCV and PCM open or short If as specified, inspect the following hydraulic passages for clogging or leakage or both: Oil pressure switch-OCV OCV-Camshaft Camshaft internal passage
If they are normal, replace the camshaft pulley (with built-in variable valve timing actuator).

Symptom Troubleshooting [Engine Control System [Mzr 2.5]]: Other Mazda 6 GJ

NO.1 MELTING OF MAIN OR OTHER FUSES [MZR 2.5]

Scheme 65

NO.2 MIL ILLUMINATES [MZR 2.5]

NO.3 WILL NOT CRANK [MZR 2.5]

Scheme 66

NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [MZR 2.5]

NO.5 ENGINE STALLS-AFTER START/AT IDLE [MZR 2.5]

NO.6 CRANKS NORMALLY BUT WILL NOT START [MZR 2.5]

NO.7 SLOW RETURN TO IDLE [MZR 2.5]

NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [MZR 2.5]

NO.9 FAST IDLE/RUNS ON [MZR 2.5]

NO.10 LOW IDLE/STALLS DURING DECELERATION [MZR 2.5]

NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [MZR 2.5]

NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [MZR 2.5]

NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZR 2.5]

NO.14 POOR FUEL ECONOMY [MZR 2.5]

NO.15 EMISSION COMPLIANCE [MZR 2.5]

NO.16 HIGH OIL CONSUMPTION/LEAKAGE [MZR 2.5]

NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR 2.5]

NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZR 2.5]

NO.19 EXHAUST SMOKE [MZR 2.5]

NO.20 FUEL ODOR (IN ENGINE COMPARTMENT) [MZR 2.5]

NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZR 2.5]

NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR 2.5]

NO.25 A/C IS NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS [MZR 2.5]

NO.26 EXHAUST SULPHUR SMELL [MZR 2.5]

NO.28 FUEL FILLING SHUT OFF CONCERNS [MZR 2.5]

NO.29 SPARK PLUG CONDITION [MZR 2.5]

Water Sprinkling Method

Scheme 67

Finding irregular signals

Locating the source of unusual signals

Scheme 68

Cooling fans do not operate

Cooling fan motor No.1 does not operate

Cooling fan motor No.2 does not operate

When idling cannot be continued

When idling can be continued

More articles — Symptom Troubleshooting [Engine Control System [Mzr 2.5]]

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