BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

Fuel Pump, Oxygen Sensor and Main Relays

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LOCATION



E30 3 Series
M20 ENGINE

The fuel pump relay is mounted on a bracket on the left inner fender in front of the shock tower. There is a grouping of 3 relays. The forward relay is the main DME relay. The middle relay is the fuel pump relay. The rear most relay is the oxygen sensor heater relay.

M42 ENGINE

The relays are mounted on the firewall above and to the right of the brake booster. The relay on the right is the main DME relay. The middle relay is the fuel pump relay. The leftmost relay is the oxygen sensor heater relay.

S14 ENGINE

The relays are located on the far right of the firewall. The relay on the right is the evaporative purge relay. The middle relay is the main DME relay. The leftmost relay is for both the oxygen sensor heater and the fuel pump.

E36 3 Series

See Figure 1



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Fig. Fig. 1: Relay and fuse box containing the fuel pump relay, oxygen sensor heater relay and the main DME relay-E36 3 Series

The relays are located in the relay and fuse box on the left side of the engine compartment. The relays will be marked on the cover of the relay and fuse box. If the cover is not available, the relays are in the row of relays closest to the engine. The forward relay is the fuel pump relay. The middle relay is the main DME relay. The rear most relay is the oxygen sensor heater relay.

E34 5 Series
M20 ENGINE

The relays are located in the electronics box at the right, rear of the engine compartment. With the lid of the electronics box removed, visible is a group of 3 relays centered in the box. The relay on the left is the main DME relay. The center relay is the fuel pump relay. The right relay is the oxygen sensor heater relay.

Some vehicles may only have the main DME relay and the fuel pump relay in the electronics box. In this case the relay on the left is the main DME relay and the right relay is the fuel pump relay.

M30 ENGINE

The relays are located in the electronics box at the right, rear of the engine compartment. With the lid of the electronics box removed, visible is a group of 3 relays centered in the box. The relay on the left is the main DME relay. The center relay is the fuel pump relay. The right relay is the oxygen sensor heater relay.

M50 ENGINE

The relays are located in the electronics box at the right, rear of the engine compartment. With the lid of the electronics box removed, visible is a group of 3 relays centered in the box. The relay on the left is the main DME relay. The center relay is the fuel pump relay. The right relay is the oxygen sensor heater relay.

S38 ENGINE

The relays are located in the electronics box at the right, rear of the engine compartment. With the lid of the electronics box removed, visible is a group of 3 relays centered in the box. The center relay is the fuel pump relay. In 1991, the relay on the left is the air pump relay and the right relay is the main DME relay. In 1992 and later, the left and right relay positions are reversed.

 
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