Fuel and Emissions Systems Symptom Troubleshooting Index (Except Touring)

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)	Troubleshoot the engine will not start, engine starts but stalls immediately, or engine is hard to start - Refer to: Fuel and Emissions Systems Symptom Troubleshooting - Engine stalls Fuel and Emissions Systems Symptom Troubleshooting - Engine will not start, engine starts but stalls immediately, or engine is hard to start .
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, immobilizer indicator stays on or flashes)	Check the immobilizer system. With keyless access system Without keyless access system
Engine starts but stalls immediately (MIL works OK, no DTCs set, immobilizer indicator stays on or flashes)	Check the immobilizer system. With keyless access system Without keyless access system
Engine is hard to start (MIL works OK, no DTCs set)	Troubleshoot the engine will not start, engine starts but stalls immediately, or engine is hard to start - Refer to: Fuel and Emissions Systems Symptom Troubleshooting - Engine stalls Fuel and Emissions Systems Symptom Troubleshooting - Engine will not start, engine starts but stalls immediately, or engine is hard to start .
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. Do the carbon accumulation check . 4. Inspect the PCV valve . 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

Symptom	Diagnostic procedure	Also check for
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
Engine stalls (MIL works OK, no DTCs set)	Troubleshoot the engine stalls - Refer to: Fuel and Emissions Systems Symptom Troubleshooting - Engine stalls Fuel and Emissions Systems Symptom Troubleshooting - Engine will not start, engine starts but stalls immediately, or engine is hard to start .
Difficult to refuel (MIL works OK, no DTCs set)	1. Check the fuel vent tube between the EVAP canister and the fuel tank. 2. Check the fuel tank vapor recirculation tube between the fuel fill pipe and the fuel tank. 3. 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
Fuel cap warning message stays on (MIL works OK, no DTCs set)	Do the troubleshooting procedure for DTC P0455 and P0456 , if the fuel cap warning message comes on frequently, or if the message does not go off after the fuel fill cap is tightened and the vehicle is driven several days. NOTE: Fuel cap warning message is monitored during the engine off natural vacuum (EONV) testing.
HDS does not communicate with the PCM or the vehicle	Troubleshoot the DLC circuit .	Correct HDS software