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.
1988 Audi 80 Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Deceleration Fuel Shutoff
- Ensure engine is at normal operating temperature and no fault codes are stored in ECU memory. Using a digital multimeter and Harness Adapter (VW1315A/1 ), check voltage at differential pressure regulator.
- Connect multimeter to differential pressure regulator. See Figure . Turn ignition on. Control voltage must read positive (+). If voltage reads negative (-), reverse test leads.
- Start engine. Raise RPM to 3000 and release throttle. Control voltage must momentarily switch to negative (-). If system fails test, perform electrical tests. See CIS-MOTRONIC VOLTAGE & RESISTANCE TESTS chart. See Figure . If system electrical tests are okay, replace ECU. Clear fault codes.
Factory Service Tools
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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.