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
When the malfunction is not identified in the diagnostic trouble code check or in the basic inspection, use this table and troubleshoot according to the priority order given below.
SFI SYSTEM:
| Symptom | Suspected Area | See Procedure |
|---|---|---|
| Engine does not crank (Does not start) | 1. Immobilizer system | HOW TO PROCEED WITH TROUBLESHOOTING |
| 2. Generator | DTC P0A1B-788 DRIVE MOTOR "A" CONTROL MODULE | |
| 3. Hybrid system | HOW TO PROCEED WITH TROUBLESHOOTING | |
| 4. Park/neutral position switch | DTC P0705-757 TRANSMISSION RANGE SENSOR CIRCUIT; DTC P0705-758 TRANSMISSION RANGE SENSOR CIRCUIT; DTC P0851-775 PARK / NEUTRAL SWITCH INPUT CIRCUIT LOW | |
| No initial combustion (Does not start) | 1. ECM (Included in Hybrid Vehicle Control ECU) power source circuit | ECM POWER SOURCE CIRCUIT |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. ECM (Included in Hybrid Vehicle Control ECU) | - | |
| Engine cranks normally but difficult to start | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Compression | INSPECTION | |
| Difficult to start with cold engine | 1. Ignition system | ON-VEHICLE INSPECTION |
| 2. Spark plug | ON-VEHICLE INSPECTION | |
| 3. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 4. Injector | INSPECTION | |
| Difficult to start with warm engine | 1. Injector | INSPECTION |
| 2. Ignition system | ON-VEHICLE INSPECTION | |
| 3. Spark plug | ON-VEHICLE INSPECTION | |
| 4. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| High engine idle speed (Poor idling) | 1. ECM (Included in Hybrid Vehicle Control ECU) power source circuit | ECM POWER SOURCE CIRCUIT |
| 2. Electronic throttle control system | ON-VEHICLE INSPECTION | |
| 3. Air induction system | - | |
| 4. PCV hose | ON-VEHICLE INSPECTION | |
| Low engine idle speed (Poor idling) | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Electronic throttle control system | ON-VEHICLE INSPECTION | |
| 3. Air induction system | - | |
| 4. PCV hose | ON-VEHICLE INSPECTION | |
| Rough idling (Poor idling) | 1. Compression | INSPECTION |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Electronic throttle control system | ON-VEHICLE INSPECTION | |
| 4. Air induction system | - | |
| 5. PCV hose | ON-VEHICLE INSPECTION | |
| Hunting (Poor idling) | 1. ECM (Included in Hybrid Vehicle Control ECU) 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 | ON-VEHICLE INSPECTION | |
| 7. Air induction system | - | |
| 8. PCV hose | ON-VEHICLE INSPECTION | |
| Hesitation/ Poor acceleration (Poor drive ability) | 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 drive ability) | 1. Spark plug | ON-VEHICLE INSPECTION |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 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 | |
| Unable/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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