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.
System - Basic Engine Control System
| SYMPTOM | Reference | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| HARD/NO START/RESTART (EXCP. HA) | ENGINE STALL | HESITATION/SURGING/FLAT SPOT | SPARK KNOCK/DETONATION | LACK OF POWER/POOR ACCELERATION | HIGH IDLE/LOW IDLE | ROUGH IDLE/HUNTING | IDLING VIBRATION | SLOW/NO RETURN TO IDLE | OVERHEATS/WATER TEMPERATURE HIGH | EXCESSIVE FUEL CONSUMPTION | EXCESSIVE OIL CONSUMPTION | BATTERY DEAD (UNDER CHARGE) | |||
| Warranty symptom code | AA | AB | AC | AD | AE | AF | AG | AH | AJ | AK | AL | AM | HA | ||
| Fuel | Fuel pump circuit | 1 | 1 | 2 | 3 | 2 | 2 | 2 | 3 | 2 | COMPONENT FUNCTION CHECK | ||||
| Fuel pressure regulator system | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | INSPECTION | ||||
| Fuel injector circuit | 1 | 1 | 2 | 3 | 2 | 2 | 2 | 2 | COMPONENT FUNCTION CHECK | ||||||
| Evaporative emission system | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | SYSTEM DESCRIPTION | ||||
| Air | Positive crankcase ventilation system | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 1 | COMPONENT INSPECTION | ||
| Incorrect idle speed adjustment | 1 | 1 | 1 | 1 | 1 | SPECIAL REPAIR REQUIREMENT | |||||||||
| Electric throttle control actuator | 1 | 1 | 2 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | DTC LOGIC , DTC LOGIC | |||
| Ignition | Incorrect ignition timing adjustment | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | SPECIAL REPAIR REQUIREMENT | |||||
| Ignition circuit | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | COMPONENT FUNCTION CHECK | ||||||
| Main power supply and ground circuit | 2 | 2 | 3 | 3 | 3 | 3 | 3 | 2 | 3 | DIAGNOSIS PROCEDURE | |||||
| Mass air flow sensor circuit | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | DTC LOGIC , DTC LOGIC | ||||||
| Engine coolant temperature sensor circuit | 3 | 3 | 3 | DTC LOGIC , DTC LOGIC | |||||||||||
| Air fuel ratio (A/F) sensor 1 circuit | DTC LOGIC , DTC LOGIC , DTC LOGIC , DTC LOGIC , DTC LOGIC | ||||||||||||||
| Throttle position sensor circuit | 2 | 2 | DTC LOGIC , DTC LOGIC , DTC LOGIC , DTC LOGIC , DTC LOGIC | ||||||||||||
| Accelerator pedal position sensor circuit | 3 | 2 | 1 | DTC LOGIC , DTC LOGIC , DTC LOGIC | |||||||||||
| Knock sensor circuit | 2 | 3 | DTC LOGIC | ||||||||||||
| Engine oil temperature sensor | 4 | 1 | 3 | DTC LOGIC , DTC LOGIC | |||||||||||
| Crankshaft position sensor (POS) circuit | 2 | 2 | DTC LOGIC | ||||||||||||
| Camshaft position sensor (PHASE) circuit | 3 | 2 | DTC LOGIC | ||||||||||||
| Vehicle speed signal circuit | 2 | 3 | 3 | 3 | DTC LOGIC | ||||||||||
| Power steering pressure sensor circuit | 2 | 3 | 3 | DTC LOGIC | |||||||||||
| ECM | 2 | 2 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | DTC LOGIC , DTC LOGIC | |||
| Intake valve timing control solenoid valve circuit | 3 | 2 | 1 | 3 | 2 | 2 | 3 | 3 | DTC LOGIC | ||||||
| VVEL control module | 3 | 4 | 4 | 3 | DTC LOGIC , DTC LOGIC | ||||||||||
| VVEL actuator motor | 3 | 4 | 4 | 3 | DTC LOGIC | ||||||||||
| VVEL actuator motor relay | 3 | 4 | 4 | 3 | DTC LOGIC | ||||||||||
| VVEL actuator shaft position sensor | 3 | 4 | 4 | 3 | DTC LOGIC | ||||||||||
| PNP signal circuit | 3 | 3 | 3 | 3 | 3 | DTC LOGIC | |||||||||
| Refrigerant pressure sensor circuit | 2 | 3 | 3 | 4 | COMPONENT FUNCTION CHECK | ||||||||||
| Electrical load signal circuit | 3 | COMPONENT FUNCTION CHECK | |||||||||||||
| Air conditioner circuit | 2 | 2 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 2 | WORK FLOW | |||
| ABS actuator and electric unit (control unit) | 4 | WORK FLOW | |||||||||||||
1 - 6: The numbers refer to the order of inspection.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.