Full Throttle Enrichment

1. Remove the plug from the coolant temp. sensor and connect the terminals together (use adapter VW 1490 or equivalent).
2. Unplug oxygen sensor
3. With ignition switched ON, activate full throttle switch.
4. Current should increase approx. 3 mA when switch is activated.
5. If the current does not increase, check;
a. Throttle switch.
b. Check for open circuit in wiring between terminals 5 and 2 of the control unit plug and full throttle switch.
6. If the wiring and the switch are OK, replace the control unit.