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15
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EMISSION COMPLIANCE
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DESCRIPTION |
Fails emissions test.
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POSSIBLE CAUSE |
• Vacuum lines leakage or blockage
• Cooling system malfunction
• Spark plug malfunction
• Leakage from intake manifold
• Erratic or no signal from CMP sensor
• Inadequate fuel pressure
• PCV valve malfunction or incorrect valve installation
• EGR valve malfunction
• Exhaust system clogging
• Fuel tank ventilation system malfunction
• Charcoal canister damage
• Air cleaner element clogging or restriction
• Throttle body malfunction
• Spark leakage from high-tension leads
• Improper air/fuel mixture ratio control operation
• Catalyst converter malfunction
• Engine internal parts malfunction
• Excessive carbon is built up in combustion chamber
• Improper engine compression
• Improper valve timing
The following troubleshooting flow chart contains fuel system diagnosis and repair procedures. Read following warnings before performing fuel system services:
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Diagnostic procedure
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STEP
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INSPECTION
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RESULTS
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ACTION
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|---|---|---|---|
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1
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Inspect for 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 okay?
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Yes
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Go to next step.
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No
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Service as necessary.
Repeat Step 1.
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2
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Connect WDS or equivalent to DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs.
Are there any DTCs displayed?
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Yes
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DTC is displayed:
Go to appropriate DTC test.
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No
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No DTC is displayed:
Go to next step.
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3
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Is any other driveability concern present?
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Yes
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Go to appropriate symptom troubleshooting.
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No
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Go to next step.
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4
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Connect WDS or equivalent to DLC-2.
Access ECT PID.
Warm up engine and run it at idle.
Verify ECT PID is correct.
(See PCM INSPECTION [L3].)
Is ECT PID correct?
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Yes
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Go to next step.
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No
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Inspect for coolant leakage, cooling fan and condenser fan operation or thermostat operation.
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5
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Is strong blue spark visible at each disconnected high-tension lead while cranking engine?
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Yes
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Inspect for following:
• Spark plugs malfunction
• Improperly installed CMP sensor
• Damage of trigger wheel on camshaft
• Open or short circuit on CMP sensor
• Open or short circuit between CMP sensor and PCM terminal 2J or 2M
Repair or replace malfunctioning parts.
If okay, go to next step.
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No
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Inspect following:
• High-tension leads
• Ignition coil and connector
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6
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Install fuel pressure gauge between fuel pipe and fuel distributor.
Start engine and run it at idle.
Measure fuel line pressure at idle.
Is fuel line pressure correct at idle?
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Yes
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Go to next step.
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No
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Zero or low:
Inspect for clogged fuel line.
If okay, replace fuel pump unit.
High:
Replace fuel pump unit.
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7
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Remove and shake PCV valve.
Does PCV valve rattle?
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Yes
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Go to next step.
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No
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Replace PCV valve.
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8
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Inspect for fuel saturation inside charcoal canister.
Is excess amount of liquid fuel present in canister?
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Yes
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Replace charcoal canister.
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No
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Inspect fuel tank vent system.
Then, go to next step.
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9
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Is there restriction in exhaust system?
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Yes
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Inspect exhaust system.
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No
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Inspect EGR system.
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10
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Inspect threeway catalytic converter.
Is threeway catalytic converter okay?
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Yes
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Inspect EGR system.
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No
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Replace threeway catalytic converter.
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11
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Verify test results.
• If okay, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM.
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