Deceleration Fuel Shut-Off

Diaphragm Pressure Regulator Testing Connections:

1. Connect an ammeter between the differential pressure regulator harness connector and the differential pressure regulator, using VOLKSWAGEN special tool #VW 1315A/1 or equivalent.

CAUTION: The small female terminals in the differential pressure regulator harness connector are easily damaged. If fabricating a test harness, use the appropriate male terminals to make connections with the harness connector.

Coolant Temperature Sensor:

2. Remove the harness connector from the coolant temperature sensor and bridge the two terminals of the connector with a jumper wire.
3. Start the engine and run at approx. 3000 RPM.
4. Close the throttle valve quickly.

5. Measure the differential pressure regulator current.

^ Differential Pressure Regulator current should change to a negative value (approx. -45 mA) briefly and then return to its normal positive value.

If the correct measurement is not obtained check the throttle switch adjustment. Refer to ADJUSTMENT PROCEDURES.
If the throttle switch adjustment is correct check the CIS-E harness. Refer to SYSTEM ELECTRICAL TESTS.
If the harness is OK the CIS-E control unit may be defective.