"Check Engine" Lamp

TEST PROCEDURE
Function Test
The control unit supplies the "Check Engine" lamp with ground potential as soon as an exhaust emission-related defect is detected. As a check, the lamp lights constantly after ignition is switched "ON" and goes out as soon as the engine is running (if no exhaust emission-related defect code is stored).

Simulate Defect
Detach connector from the air mass meter and start engine. The fault lamp must then light when the defect code 41 Air mass meter is detected by the control unit.

Possible Defect Cause
- Control unit does not output the ground signal for the "Check Engine" lamp.
- Wires or "Check Engine" lamp defective.