Tr Signal/EKP Relay

Up to model year 1989 uses a 4-pin EKP relay. Relay switches on as soon as the DME control unit sends a ground signal with overlaid engine speed signal (once per crankshaft revolution) at Pin No. 3. On model year 1989 and later, EKP relay switches only during starting (via terminal No. 50) or when an ignition signal (terminal No. 1) is applied. Possible causes:

• Wire to EKP relay defective.
• EKP relay or main relay defective.
• Voltage supply for DME control unit, relay 1 or 2 defective.
• No signals from the pulse generator engine-speed/position.
• Ignition output stage or ignition coil defective (1989 model only).