Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Problem Symptoms Table
HINT:
When a malfunction is not confirmed by a DTC (Diagnostic Trouble Code) check and the cause of problem cannot be identified through a basic inspection, troubleshoot according to the priority order indicated in the table below.
| Symptom | Suspected area |
|---|---|
| Engine does not crank (does not start) | 1. STARTER |
| 2. STARTER RELAY | |
| 3. Park/Neutral position switch circuit*1 (ON-VEHICLE INSPECTION ) | |
| 4. CLUTCH START SWITCH *2 | |
| No initial combustion (does not start) | 1. ECM POWER SOURCE CIRCUIT |
| 2. VC OUTPUT CIRCUIT | |
| 3. IGNITION COIL CIRCUIT | |
| 4. FUEL PUMP CONTROL CIRCUIT | |
| 5. Injector (INSPECTION ) | |
| Incomplete combustion (does not start) | 1. FUEL PUMP CONTROL CIRCUIT |
| 2. IGNITION COIL CIRCUIT | |
| 3. Injector (INSPECTION ) | |
| Engine cranks normally but difficult to start | 1. STARTER SIGNAL CIRCUIT |
| 2. IAC VALVE CIRCUIT | |
| 3. FUEL PUMP CONTROL CIRCUIT | |
| 4. IGNITION COIL | |
| 5. Spark plug (ON-VEHICLE INSPECTION ) | |
| 6. Compression (ON-VEHICLE INSPECTION ) | |
| 7. Injector (INSPECTION ) | |
| Difficult to start with cold engine | 1. STARTER SIGNAL CIRCUIT |
| 2. IAC VALVE CIRCUIT | |
| 3. FUEL PUMP CONTROL CIRCUIT | |
| 4. Injector (INSPECTION ) | |
| 5. IGNITION COIL | |
| 6. Spark plug (ON-VEHICLE INSPECTION ) | |
| Difficult to start with warm engine | 1. STARTER SIGNAL CIRCUIT |
| 2. IAC VALVE CIRCUIT | |
| 3. FUEL PUMP CONTROL CIRCUIT | |
| 4. Injector (INSPECTION ) | |
| 5. IGNITION COIL | |
| 6. Spark plug (ON-VEHICLE INSPECTION ) | |
| Incorrect fast idle (poor idling) | 1. IAC VALVE CIRCUIT |
| High engine idling speed (poor idling) | 1. IAC VALVE CIRCUIT |
| 2. ECM POWER SOURCE CIRCUIT | |
| 3. Park/Neutral position switch circuit*1 (ON-VEHICLE INSPECTION ) | |
| Low engine idling speed (poor idling) | 1. IAC VALVE CIRCUIT |
| 2. Park/Neutral position switch circuit*1 (ON-VEHICLE INSPECTION ) | |
| 3. FUEL PUMP CONTROL CIRCUIT | |
| 4. Injector (INSPECTION ) | |
| Rough idling | 1. IAC VALVE CIRCUIT |
| 2. Injector (INSPECTION ) | |
| 3. IGNITION COIL | |
| 4. Compression (ON-VEHICLE INSPECTION ) | |
| 5. FUEL PUMP CONTROL CIRCUIT | |
| Hunting (poor idling) | 1. IAC VALVE CIRCUIT |
| 2. ECM POWER SOURCE CIRCUIT | |
| 3. FUEL PUMP CONTROL CIRCUIT | |
| Hesitation/Poor acceleration (poor driveability) | 1. Injector (INSPECTION ) |
| 2. FUEL PUMP CONTROL CIRCUIT | |
| 3. IGNITION COIL CIRCUIT | |
| Muffler explosion, after fire (poor driveability) | 1. IGNITION COIL |
| 2. Spark plug (ON-VEHICLE INSPECTION ) | |
| 3. Injector (INSPECTION ) | |
| Surging (poor driveability) | 1. FUEL PUMP CONTROL CIRCUIT |
| 2. Spark plug (ON-VEHICLE INSPECTION ) | |
| 3. Injector (INSPECTION ) | |
| Engine stalls soon after starting | 1. FUEL PUMP CONTROL CIRCUIT |
| 2. IAC VALVE CIRCUIT | |
| Engine stalls when accelerator pedal released | 1. Injector (INSPECTION ) |
| 2. IAC VALVE CIRCUIT | |
| 3. ECM | |
| Engine stalls when shifting from N to D | 1. Park/Neutral position switch circuit*1 (ON-VEHICLE INSPECTION ) |
| 2. IAC VALVE CIRCUIT | |
| Unable/difficult to refuel | 1. Refueling valve (canister) |
HINT:
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Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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