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
Optical sensor provides a high resolution signal to PCM by counting pulses on sensor disk located in injection pump. High resolution is an important input by PCM for fuel control and timing. Test monitors number of high resolution pulses that have been missed (not detected). Number of pulses detected since last pump cam pulse is compared to number of pulses that should have occurred.
DTC will set when the following conditions are present:
- A number of high resolution pulses (internal to PCM) per every 8 cam reference pulses.
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.