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.
Circuit Description
Timing of combustion is accomplished by delivering a pulse of fuel into combustion chamber at a desired degree of cylinder travel. This desired degree (desired timing) defines current position of cylinder in relationship to top dead center. This test compares desired timing to measured timing when certain conditions are met. To retard injection timing, PCM extends stepper motor. To advance injection timing, PCM retracts stepper motor.
DTC will set when the following conditions are present:
- Engine speed has not changed more than 56 RPM for 20.8 seconds.
- A 5 degree difference between actual injection time and desired injection time exists.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.