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.
Diagnosis Procedure
- CHECK FUEL INJECTOR POWER SUPPLY CIRCUIT
- Turn ignition switch OFF.
- Disconnect fuel injector harness connector.
- Turn ignition switch ON.
- Check the voltage between fuel injector harness connector and ground.VOLTAGE REFERENCE
Fuel injector Ground Voltage Cylinder Connector Terminal 1 F121 1 Ground Battery voltage 2 F122 1 3 F123 1 4 F124 1 5 F125 1 6 F126 1 Is the inspection result normal?
YES: GO TO 3.
NO: GO TO 2.
- DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E20, F40
- Harness connectors F30, F120
- IPDM E/R harness connector E7
- 10 A fuse (No. 44)
- Harness for open or short between fuel injector and fuse
Repair open circuit, short to ground or short to power in harness or connectors.
- CHECK FUEL INJECTOR OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
- Turn ignition switch OFF.
- Disconnect ECM harness connector.
- Check the continuity between fuel injector harness connector and ECM harness connector.CONTINUITY REFERENCE
Fuel injector ECM Continuity Cylinder Connector Terminal Connector Terminal 1 F121 2 F102 89 Existed 2 F122 2 85 3 F123 2 81 4 F124 2 90 5 F125 2 86 6 F126 2 82 - Also check harness for short to ground and short to power.
Is the inspection result normal?
YES: GO TO 5.
NO: GO TO 4
- DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors F30, F120
- Harness for open or short between fuel injector and ECM
Repair open circuit, short to ground or short to power in harness or connectors.
- CHECK FUEL INJECTOR
Refer to "COMPONENT INSPECTION ".
Is the inspection result normal?
YES: GO TO 6.
NO: Replace malfunctioning fuel injector.
- CHECK INTERMITTENT INCIDENT
Refer to "INTERMITTENT INCIDENT ".
Is the inspection result normal?
YES: Replace IPDM E/R.
NO: Repair open circuit, short to ground or short to power in harness or connectors.
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.