NO.15 EMISSION COMPLIANCE [MZI-3.7]

id0103d2802100

15 | EMISSION COMPLIANCE
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DESCRIPTION | • Fails emissions test.
POSSIBLE CAUSE | • Vacuum lines leakage or blockage • Disconnected electrical system connector • Maintenance schedule is not followed. • Leakage from intake manifold • Air cleaner element clogging or restriction • Throttle body restrict or clogged • PCM DTC is stored. • Cooling system malfunction • Fuel-filler cap malfunction • Ignition system malfunction ― Ignition coil malfunction ― Ignition coil related circuit malfunction ― Spark plug malfunction • Inadequate fuel pressure ― Fuel pump mechanical malfunction ― Fuel line restriction or clogging ― Pressure regulator malfunction (built-in fuel pump unit) • Improper air/fuel mixture ratio control operation • Bend or open circuit A/F sensor wiring harness • Exhaust system clogging • Improper engine compression • PCV valve malfunction or incorrect valve installation • Fuel tank ventilation system malfunction • Charcoal canister damage • Catalyst converter malfunction • Engine internal parts malfunction ― Excessive carbon is built up in combustion chamber. ― Improper valve timing 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 [MZI-3.7].)(See AFTER SERVICE PRECAUTION [MZI-3.7].) Caution • Disconnecting/connecting quick release connector without cleaning it may cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Inspect for the following: • Vacuum lines for leakage or blockage • Electrical connections • Proper maintenance schedule followed • Intake-air system and air cleaner element concerns: obstructions, leakage or dirtiness Are all items normal? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2 | Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Are there any DTCs displayed? | Yes | DTC is displayed: • Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7].)
No | No DTC is displayed: • Go to the next step.
3 | Is any other driveability concern present? | Yes | Go to the appropriate symptom troubleshooting.
No | Go to the next step.
4 | Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Warm up the engine and idle it. Is the ECT PID normal? (See PCM INSPECTION [MZI-3.7].) | Yes | Go to the next step.
No | Inspect for following: • Coolant leakage • Cooling fan and condenser fan operations • Thermostat operation Repair or replace the malfunctioning part according to the inspection results.
5 | Inspect the fuel-filler cap. Is there any leakage at the fuel-filler cap? | Yes | Replace the fuel-filler cap.
No | Go to the next step.
6 | Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].) Is strong blue spark visible at each cylinder? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
7 | Install the fuel pressure gauge between fuel pipe and fuel distributor. Start the engine and run it at idle. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7].) Is the fuel line pressure correct during idle? | Yes | Go to the next step.
No | Zero or low: • Inspect the following: ― Fuel pump relay ― Fuel pump circuit ― Fuel line for clogging • If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].) High: • Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].)
8 | Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [MZI-3.7].) Is there any malfunction? | Yes | Inspect the following: • Exhaust gas leakage • A/F sensor installation Repair or replace the malfunctioning part according to the inspection results. • If normal, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI-3.7].)
No | Go to the next step.
9 | Visually inspect the exhaust system part. Is there any deformed exhaust system part? | Yes | Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
10 | Is the engine compression correct? | Yes | Go to the next step.
No | Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
11 | Note • The PCV valve cannot be reassembled once it is removed because the tabs will have bee n broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI-3.7].) Is the PCV valve normal? | Yes | Go to the next step.
No | Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7].)
12 | Inspect for fuel saturation inside charcoal canister. Is excess amount of liquid fuel present in canister? | Yes | Replace the charcoal canister. (See CHARCOAL CANISTER, CANISTER VENT (CV) SOLENOID VALVE, AIR FILTER COMPONENT REMOVAL/INSTALLATION [MZI-3.7].)
No | Inspect the fuel tank vent system. (See FUEL TANK INSPECTION [MZI-3.7].) Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
13 | Inspect the three-way catalytic converter. (See EXHAUST SYSTEM INSPECTION [MZI-3.7].) Is the three-way catalytic converter normal? | Yes | Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results. • If the valve timing is normal, inspect the following engine internal part, such as excessive carbon is built-up in combustion chamber. • Repair or replace the malfunctioning part according to the inspection results.
No | Replace the three-way catalytic converter. (See EXHAUST SYSTEM REMOVAL/INSTALLATION [MZI-3.7].)
14 | • Verify test results. ― If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].) ― If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7].)