Fuel and Emissions Systems Symptom Troubleshooting Index

Fuel and Emissions Systems Symptom Troubleshooting Index

Symptom Troubleshooting Index

When the vehicle has one of these symptoms, check for a diagnostic trouble code (DTC) with the HDS. If there is no DTC, do the diagnostic procedure for the symptom, in the sequence listed, until you find the cause- Symptom

Diagnostic procedure

Also check for

Engine will not start(MIL works OK, no DTCs set)

1- Troubleshoot the engine will not start, engine starts but stalls immediately, or engine is hard to start- 2- CVT, A/T: Do the CVT system symptom troubleshooting or A/T system symptom troubleshooting

Engine will not start and HDS does not communicate with the PCM(MIL comes on and stays on, no DTCs set)

PCM power and ground circuit troubleshooting- MIL comes on and stays on, or never comes on at all, no DTCs set

Troubleshoot the MIL circuit- Engine will not start(MIL works OK, no DTCs set, security indicator stays on or flashes)

Check the keyless access system- Engine starts but stalls immediately(MIL works OK, no DTCs set, security indicator stays on or flashes)

Check the keyless access system- Engine is hard to start(MIL works OK, no DTCs set)

1- Troubleshoot the engine will not start, engine starts but stalls immediately, or engine is hard to start- 2- Do the CVT system symptom troubleshooting or A/T system symptom troubleshooting

Cold fast idle too low(MIL works OK, no DTCs set)

1- Do the PCM idle learn procedure- 2- Check the idle speed- 3- Do the carbon accumulation check- Cold fast idle too high(MIL works OK, no DTCs set)

1- Do the PCM idle learn procedure- 2- Check the idle speed- Intake air leaks

Idle speed fluctuates(MIL works OK, no DTCs set)

1- Do the PCM idle learn procedure- 2- Check the idle speed- 3- Check the fuel pressure- 4- Do the carbon accumulation check- 5- Troubleshoot the A/C signal circuit- 6- Check the A/C refrigerant amount- NOTE: Turning the A/C to ON under the conditions that the A/C refrigerant amount is out of specification (excessive or too little) may cause the idle speed fluctuation-

Incorrect valve adjustment

Intake air leaks

After warming up, idle speed is below specifications without load(MIL works OK, no DTCs set)

Do the carbon accumulation check- Incorrect valve timing or clearance adjustment

After warming up, idle speed is above specifications without load(MIL works OK, no DTCs set)

Inspect the APP sensor- Intake air leaks

Low power(MIL works OK, no DTCs set)

1- Check the fuel pressure- 2- Check the air cleaner element-

Low compression

Incorrect camshaft timing

Incorrect engine oil level

Exhaust restriction

Fuel contamination

Intercooler insufficient cooling (for some models)

Engine stalls(MIL works OK, no DTCs set)

Troubleshoot the engine stalls- Difficult to refuel(MIL works OK, NO DTCs set)

1- Check the fuel vent tube between the EVAP canister and the fuel tank unit- 2- Check the fuel tank vapor recirculation tube between the fuel fill pipe and the fuel tank unit- 3- Insert the emergency fuel funnel into the fuel filler neck, then check the operation of the shut-off valve flap- NOTE: The emergency fuel funnel is stored in the trunk tool box- 4- Replace the fuel tank- Malfunctioning gas station filling nozzle

Fuel overflows during refueling(No DTCs set)

Replace the fuel tank- Malfunctioning gas station filling nozzle

HDS does not communicate with the PCM or the vehicle

Troubleshoot the DLC circuit.- Correct HDS software

See also:
Engine low power
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