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.
1991 Audi 100 BaseFACTORY OEM SERVICE PROCEDURE
Cold Engine Warm-Up Enrichment
- Using Adapter Cable (US 1112), connect Green test lead to OXS system test connector (Blue/Black wire) located near fuel filter. Connect Dwell Meter (VW 1367) to vehicle. Set the "%" button on dwell meter.
- Ensure engine temperature is less than 68°F (20°C). Start engine. Duty cycle should be at least 80%. After 30-60 seconds, duty cycle should gradually drop. If duty cycle is as specified, check coolant sensor and related wiring circuits. If coolant sensor and wiring circuits are okay, replace ECU.
Factory Service Tools
Use the Manual With the Right Hardware
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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.