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Bosch Motronic Info

Motronic ECU Pinout for the ABY Engine

IMPORTANT - The information on this page is ONLY applicable to the ABY (and ADU/RS2) engine. Wire colors may vary..

Wire colours and pin information are extracted from Edition 07.94 of the Audi 80 schematics. This is the latest / greatest version available. 

The image below depicts the ABY ECU pinout when viewing the cable assembly.

ECU Cable

The following table defines the functionality of each of the 55 pins on the ABY Motronic ECU. 

Pin
Function / Assignment
Input or Output wrt ECU Schematic References Wire Colour at ECU 
01
Power output stage for ignition, cylinder #1

OUTPUT

N122 pin I1 gn/ws
02
Power output stage for ignition, cylinder #2

OUTPUT

N122 pin I2
li
03

Fuel Pump Relay, 0V. Also provides 12V power for various components.

OUTPUT (0V)

J17

br/gn
04
Idle Air Control Valve, 0V

OUTPUT (0V)

N71 pin 2
gn/sw
05
Evaporative emissions frequency valve, 0V

OUTPUT (0V)

N80 pin 1
ws
06
Air conditioning compressor control. Normally an input in conjuction with pin 41 , but can also be used to turn off A/C compressor when maximum engine power is required

INPUT / OUTPUT

A/C
gn/sw
07
Mass Air Flow (MAF) sensor signal
INPUT
G70 pin 3
sw/ws
08
Camshaft Position Sensor (Hall Sender), Pin #2
INPUT
G40 pin 2
gn
09
Barometric pressure sensor
INPUT
F96 pin 1
gr
10
0V ground/shield for various sensors
0V
G39, G70, G4, G28, G61, G66, F60, G40
br/ge
11
Knock sensor I (For cylinders 1 - 3)
INPUT
G61
ws
12
+5V reference voltage for various sensors
OUTPUT
G69 pin 1, G40 pin 1,
F96 pin2
ro/sw
13
OBD connector (L-wire)
INPUT
OBD
ws/ro
14
0V ground
0V
-
br/ro
15
Not Used
-
-
-
16
Fuel injector -ve pulse, cylinder #5
OUTPUT
N83 pin 2
br/ro
17
Fuel injector -ve pulse, cylinder #2
OUTPUT
N31 pin 2
br/bl
18
Permanent 12V supply voltage
12V INPUT
S27
ro/ws
19
0V ground/shield for various sensors
0V
G39, G70, G4, G28, G61, G66, F60, G40
br/ge
20
Power output stage for ignition, cylinder #4
OUTPUT
N127 pin I1
ro/sw
21
Power output stage for ignition, cylinder #5
OUTPUT
N127 pin I2
gn
22
OBD for Malfunction Indicator Lamp (MIL) - Blink Codes
OUTPUT
OBD
gr/br
23
Power output stage for ignition, cylinder #3
OUTPUT
N122 pin I3
sw/bl
24
0V ground
0V
-
br/ro
25
Mass Air Flow (MAF) sensor, burn-off signal
OUTPUT
G70 pin 4
bl/li
26
Mass Air Flow (MAF) sensor, electrical ground
INPUT
G70 pin 2
sw/gn
27
Switched 12V supply voltage (Ignition ON)
12V INPUT
S32
sw
28
Oxygen / Lambda sensor
INPUT
G39
gn
29
Knock sensor I (For cylinders 4, 5)
INPUT
G66
gn
30
0V ground
0V
G61, G66. G69, F96, G62, G42
sw/li
31
Fuel consumption signal
OUTPUT
J128/189
br/sw
32
Charge pressure signal (NOT used on the S2)
OUTPUT
-
-
33
Wastegate frequency valve control signal (Switched 0V)
OUTPUT
N75 pin 2
gn/ge
34
Fuel injector -ve pulse, cylinder #3
OUTPUT
N32 pin 2
br/gn
35
Fuel injector -ve pulse, cylinder #4
OUTPUT
N33 pin 2
br/ws
36
Fuel injector -ve pulse, cylinder #1
OUTPUT
N30 pin 2
br/sw
37
Switched 12V supply voltage (via fuel pump relay - activated by ECU). Also related to 'holdover relay' with ECU for the MAF. Probably for burnoff - assuming that pin 25 burnoff trigger is a 0V output pulse. In which case this pin is pulled to 12V with the engine running and is used to empower the MAF burnoff sequence with the engine off.
12V
N30, N31, N32, N33, N83, G70
bl/sw
38
Coding Plug (where applicable)
INPUT
-
br/bl
39
Coding Plug (where applicable)
INPUT
-
ws/sw
40
Engine speed signal (RPM)
OUTPUT
G5 (Tacho)
li
41
Air conditioning status - informs the ECU if A/C is ON or OFF
INPUT
A/C
sw/ge
42
Not Used
-
-
-
43
Not Used
-
-
-
44
Intake air temperature
INPUT
G42
sw/ge
45
Coolant temperature
INPUT
G62
ro/gn
46
Multi-Function Thermal Switch
INPUT
F76 pin 2 (R)
bl/ws
47
Crankshaft reference position sensor (62 degrees BTDC on cylinder #1)
INPUT
G4
ro
48
0V reference for crankshaft sensors.
0V
G4, G28
li-G4
gr-G28
49
Crankshaft speed sensor (135 teeth on flywheel starter ring)
INPUT
G28
bl
50
Vehicle speed signal (VSS from speedometer)
INPUT
G21
ws/bl
51
Not Used
-
-
-
52
Throttle position switch (Idle detection)
INPUT
F60 pin 6
gn/li
53
Throttle position potentiometer (Throttle angle)
INPUT
G69 pin 3
gn/bl
54
Not Used
-
-
-
55
OBD connector (K-wire)
INPUT / OUTPUT
OBD
gn/ro

Last Updated 2nd September 2008