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:
Use the table below to help determine the cause of the problem symptoms. The potential causes of the symptoms are listed in order of probability in the "Suspected area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
SFI system
| Symptom | Suspected Area | See |
|---|---|---|
| Engine does not crank (does not start) | 1. Starter | INSPECTION |
| 2. Starter relay | STARTER RELAY | |
| 3. Ignition switch | REMOVAL | |
| 4. VC Output Circuit | VC OUTPUT CIRCUIT | |
| No initial combustion (does not start) | 1. ECM power source circuit | ECM POWER SOURCE CIRCUIT |
| 2. VC Output Circuit | VC OUTPUT CIRCUIT | |
| 3. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 4. ECM | REMOVAL | |
| Engine cranks normally (difficult to start) | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Compression | ENGINE | |
| Cold engine (difficult to start) | 1. Starter signal circuit | DTC P0617 STARTER RELAY CIRCUIT HIGH |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Spark plug | ON-VEHICLE INSPECTION | |
| 4. Ignition system | ON-VEHICLE INSPECTION | |
| 5. Injector | INSPECTION | |
| Hot engine (difficult to start) | 1. Starter signal circuit | DTC P0617 STARTER RELAY CIRCUIT HIGH |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Spark plug | ON-VEHICLE INSPECTION | |
| 4. Ignition system | ON-VEHICLE INSPECTION | |
| 5. Injector | INSPECTION | |
| High engine idle speed | 1. A/C signal circuit (compressor circuit) | COMPRESSOR CIRCUIT |
| 2. ECM power source circuit | ECM POWER SOURCE CIRCUIT | |
| 3. Electronic throttle control circuit | DTC P2102 Throttle Actuator Control Motor Circuit Low; DTC P2103 Throttle Actuator Control Motor Circuit High | |
| 4. Air induction system | IACV CONTROL CIRCUIT | |
| 5. PCV hose | - | |
| Low engine idle speed | 1. A/C signal circuit (compressor circuit) | COMPRESSOR CIRCUIT |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Electronic throttle control circuit | DTC P2102 Throttle Actuator Control Motor Circuit Low; DTC P2103 Throttle Actuator Control Motor Circuit High | |
| 4. Air induction system | IACV CONTROL CIRCUIT | |
| 5. PCV hose | - | |
| Rough idling | 1. Compression | ENGINE |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Electronic throttle control system | DTC P2102 Throttle Actuator Control Motor Circuit Low; DTC P2103 Throttle Actuator Control Motor Circuit High | |
| 4. Air induction system | IACV CONTROL CIRCUIT | |
| 5. PCV hose | - | |
| Hunting (when idling) | 1. ECM power source circuit | ECM POWER SOURCE CIRCUIT |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Spark plug | ON-VEHICLE INSPECTION | |
| 4. Ignition system | ON-VEHICLE INSPECTION | |
| 5. Injector | INSPECTION | |
| 6. Electronic throttle control system | DTC P2102 Throttle Actuator Control Motor Circuit Low; DTC P2103 Throttle Actuator Control Motor Circuit High | |
| 7. Air induction system | IACV CONTROL CIRCUIT | |
| 8. PCV hose | - | |
| Hesitation / Poor acceleration (poor driveability) | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Spark plug | ON-VEHICLE INSPECTION | |
| 3. Ignition system | ON-VEHICLE INSPECTION | |
| 4. Injector | INSPECTION | |
| Surging (poor driveability) | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Spark plug | ON-VEHICLE INSPECTION | |
| 3. Ignition system | ON-VEHICLE INSPECTION | |
| 4. Injector | INSPECTION | |
| Engine stalls soon after starting | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Spark plug | ON-VEHICLE INSPECTION | |
| 3. Ignition system | ON-VEHICLE INSPECTION | |
| 4. Injector | INSPECTION | |
| Engine stalls during A/C operation | 1. A/C signal circuit (compressor circuit) | COMPRESSOR CIRCUIT |
| 2. ECM | REMOVAL | |
| Usable / difficult to refuel | Refueling valve (canister) | REMOVAL |
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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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