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.
Catalytic Converter Protection Function (Ignition Circuit Monitoring)
In the DME M1.7 system, the cylinder reference point sensor is used for ignition circuit monitoring. See Figure . If the cylinder reference point sensor detects no ignition signal on ignition lead 6 (or 12), the supply of fuel is cut by shortening the injection signal. However, the signal is not cut completely to ensure that EML system does not revert to the emergency program. The vehicle can still be driven with the remaining row of cylinders. The cylinder reference point sensor therefore monitors the entire primary side and the cylinder 6 or 12 on the secondary side.
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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.