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.
DTC P1020: Fuel Injector Control Circuit: Description
The PCM controls fuel delivery and determines fuel system operation on Bi-Fuel (KL6) vehicles. The PCM is not capable of operating the high current CNG fuel injectors. When CNG operation is commanded, the PCM grounds the AF enable circuit, which energizes the AF relay. The AF relay energizes all of the AF injector relays. The PCM injector control signals are routed through the AF injector relays to the Fuel Injector Control Module (FICM). The FICM generates duplicate control signals to operate the CNG injectors. When gasoline operation is commanded, the PCM opens the AF enable circuit, which de-energizes the AF relay, and all of the AF injector relays. The fuel injector control circuits are routed through the AF injector relays to the gasoline fuel injectors. A fused ignition voltage is supplied to all of the fuel injectors. The PCM monitors the status of each injector signal circuit. DTC P1020 will set if there is condition on any one of the fuel injector signal circuits, or AF injector relays.
NO RELATED
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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.