Warm Start Enrichment

TEST CONDITIONS
- coolant temperature sensor OK
- VW 1367 connected for duty cycle reading
- coil wire from terminal 4 securely grounded
- disconnect wire from temperature sensor (arrow)

Using an additional sensor Part no. 035 919 501, which has been cooled to below 20°C (68°F):
- connect open sensor wire to new sensor and ground body of new sensor with jumper cable
- crank engine with starter
- specification: approx. 80% duty cycle (constant)

If duty cycle reading NOT OK
- replace control unit

If duty cycle reading OK, with difficulties when cold starting
- check cold start valve and idle stabilization system