Procedure After Voltage Supply Open Circuit

Procedure After Voltage Supply Open Circuit

If the voltage supply is interrupted, the engine control module looses all "learned" and/or "reference" values. Driveability problems may occur depending on vehicle mileage.

Special tools and equipment
- VAG1551 or VAG1552 Scan Tool (ST) with VAG 1551/3 adapter cable

Work Sequence
- Switch ignition on for at least 10 seconds.
- Switch ignition off.
- Throttle valve control module adapted to ECM. Testing and Inspection
- Perform idle speed check, refer to "On Board Diagnostic (OBD II)/Function Checking/Idle Check". Testing and Inspection

NOTE: During idle speed check the EVAP canister purge regulator valve and the air conditioner are switched off and the oxygen sensor regulation learning procedure is initiated.

- Perform long test drive until poor driveability characteristics are eliminated.

WARNING!
When driving or riding in an airbag-equipped vehicle, NEVER hold the scan tool or other test equipment in your hands or lap while in motion. Objects between you and the airbag increase the risk of injury in an accident.
During a test drive in an airbag-equipped vehicle, test equipment must always be fastened to and operated from the rear seat by a second technician.

During the road test the following operating conditions must be fulfilled:
- The engine coolant temperature must exceed 80°C (176°F) See VAG1551 scan tool function 08, display group 004, display field 3, refer to "On Board Diagnostic (OBD II). Testing and Inspection
- When the temperature is reached, the operating conditions must be attained several times (idle, part throttle, full throttle, deceleration, enrichment).
- At full throttle the engine speed must exceed 3500 RPM.