Updated 3/11/2003

| 35 pin L - Jetronic |
Seen into the female connectors.

1. Ignition coil - (from tach) 19. No connection
2. Throttle switch, idle (short wire on switch) 20. From AFM pump contact
(also to Combo relay 86b +) engine running
3. Throttle switch, WOT (long wire on switch) 21. No connection
4. Pin 50 via main relay 22. No connection
5. Earth connection for coolant sensor (G100) 23. O2 sensor shield (gnd) (NC on non lambda)
6. Air flow sensor (0 volts) 24. O2 sensor (green wire) (NC on non lambda)
7. Air flow sensor signal (0 - 7.5V) 25. No connection
8. Air flow sensor reference ( 7.5V) 26. No connection
9. Air flow sensor +12V (joined to pin 12 for high altitude) 27. Air flow sensor air temp.
10. Combo relay, pin 88a (ignition on) 28. Ground for combo relay 85 (528i)
11. No connection 29. Ignition on from combo relay 88b (528i)
12. High Altitude (non-lambda units only 30. Injector 5
13. Coolant temperature sensor 31. Injector 6
14. Injector 4 32. Injector 3
15. Injector 1 33. Injector 2
16. Earth connection (G99) 34. Auxiliary air valve - , bimetal
17. Earth connection (G99) 35. Earth connection (G99)
18. Throttle switch + (common to idle and WOT)  


528i Combo Relay Pinout

Pin Wire size & color Signal Type
Pin Wire size & color Signal Type
86a 1.5mm bk/yl start signal from igntion switch (starter solenoid) I 86 1mm wt starting (cold start valve and ecu) O
88y 1.5mm gn/yl from fuse #1 (16 amp; fuel pump supply) P 88d 1.5mm gn/vl to fuel pumps O
85 1mm wt relay coil gnd from ecu G 86c 1.5mm gn start run bus from ignition switch 15 (not fused) I
88a 1mm wt ignition on (switched by start/run bus) O 88b 2.5mm wt +12V power to injectors 4-6 O
86b 1mm wt engine running I 88e 2.5mm wt +12V power to injectors 1-3 O
88z 4mm rd battery +12V (not fused) P 88c 1mm wt +12V for cold start valve O

*I=input O=output P=Power G=ground


Engine Connector Pinout




Pin Wire
Signal Type
1 1.5 bk/yl Starter solenoid voltage (+12 when cranking) O 5 1 bk Coil negative terminal to tach and L-jet ECU pin 1 (single female connector near ecu socket) I
2 1.5 gn/yl Start/run bus through fuse 1;
To terminal 88y combo relay
(to aux air valve 88c and fuel pump88d
when cranking )
P 6 bn/wt temp guage sensor I
3 1 blue Alt warning light to alt - also supplies field
coil voltage through warning light bulb to
allow charging. +12V when car running
I/O 7 bn/gn To oil pressure switch (grounded when no pressure) I
4 1.5 gn Start/run bus - +12V when key is in run
O 8 gn/violet Power to fuel pumps P

*I=input O=output P=Power G=ground; all with respect to fuse box.

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