Fuel Pump Relay

TEST PROCEDURE:

Function Check:
The Fuel Pump Relay (EKP) switches on as soon as the Digital Motor Electronic (DME) control unit outputs a ground signal at Pin 1 with overlaid engine speed signal (once per crankshaft revolution). In addition, at ignition "ON", the EKP relay is briefly activated by the DME in order to build up the necessary fuel pressure before starting. The voltage increase can be measured at fuse F23.

Possible Causes for Defect:
- Wire to EKP relay defective.
- EKP relay or main relay defective.
- Voltage supply for DME control unit, DME relay 1 or 2 not "OK".
- No signals from crankshaft position sensors (engine speed/position sensor).