BMW 745i Motronic Interconnections - Engine side

These interconnection numbers refer to the connection numbering in the "Engine wire harness overview".
If you use this information with the overview and the schematic diagram you have quite complete picture of the whole engine management system. Many non-745i owners have asked for this information as they plan to install 745 engine into their car and sometimes also want to use or modify existing wire harness instead of 745i original.

How to read the interconnection codes:
Motronic and Knock Sensor Box pin numbers are the real and correct pin numbers. Interconnection numbers on all other parts are imaginative as in most cases there are no numbers available. However, wire colors and descriptions help you to identify each connection quite precisely. Examples:
1.13 to 23.1 : Motronic Box pin 13 is connected to Engine Temperature Sensor "959". In the section 23 you can see that it's wire color is Brown Red and that it is the signal wire of that sensor as the other terminal is connected to ground.
4.3 to 1.1, 20.4, 29 : Connector "A" pin 3 is connected to Motronic pin 1, Diagnostics Socket pin 4 and to Ignition Coil -. Wire color is Black.
Note that wire colors between interconnections are always the same.

I will add the same information on Motronic to Transmission side. Once that is done all the material will be put into one PDF file, which will be easier to download and print. That part will also include modification instructions for those who want to use manual transmission with 745i engine.


No:1 * BMW Drawing no: 931 * Motronic 0261 200 013 *
Pin no: Interconnection numbers Connected to:
1.1 29, 30, 4.3, 20.4 Ignition Coil -, Connector A, Diagnostics socket
1.2 20b.4 Throttle Switch "952"
1.3 2.13 Knock Sensor Box, Pin no: 13
1.4 35, 22.1, 15.1, 2.17, 38.7, 20.1 Starter relay, Cold start switch, Cold start injector, Knock sensor box, Dashboard connector, Diagnostics Socket
1.5 - Ground, shielded ground for crankshaft position indicator
1.6 18.4 Airflow Meter "953", ground
1.7 18.2 Airflow Meter "953" , output voltage to A/D Converter
1.8 7.2 RPM Sensor "928"
1.9 18.3 Airflow Meter "953"
1.10 NC No Connection
1.11 4.1 Connector "A" to Dashboard Computer
1.12 NC No Connection
1.13 23.1 Engine Temp. Sensor "959"
1.14 16.1, 24.1, 25.1 Injectors 1, 2 and 3 "955"
1.15 12.1, 13.1, 14.1 Injectors 4, 5 and 6 "955"
1.16 39 Battery -
1.17 39 Battery -
1.18 5.3 Relay 2 "966"
1.19 - Ground
1.20 37.3 Relay 1 "965"
1.21 2.24 Knock Sensor Box, Pin no: 24
1.22 18.1 Airflow Meter / Air Temp. Sensor "953"
1.23 7.3 RPM Sensor, shielded ground "928"
1.24 2.16 Knock Sensor Box, Pin no: 16
1.25 8.1 Crankshaft Position Indicator "929"
1.26 8.2 Crankshaft Position Indicator "929"
1.27 7.1 RPM Sensor "928"
1.28 NC No Connection
1.29 NC No Connection
1.30 6.2 Air Pressure Potentiometer "986"
1.31 NC No Connection
1.32 NC No Connection
1.33 NC No Connection
1.34 NC No Connection
1.35 3.4, 2.25, 5.4 Connector "B", Knock Sensor Box, Relay 2

No 2 * BMW Drawing no: 948 * Knock Sensor Box 0 261 201 003 *
Pin no: Interconnection numbers Connected to:
2.1 NC No Connection
2.2. 19.2 Turbo Pressure Valve "977"
2.3 NC No Connection
2.4 NC No Connection
2.5 3.2 Connector "B" to automatic transmission
2.6 10.1 Knock Sensor 2 "949"
2.7 3.3 Connector "B" to automatic transmission
2.8 B20.3 Throttle potentiometer "952a", input voltage
2.9 26.1 Knock Sensor 1 "949"
2.10 26.2, 10.2 Shielded ground for both Knock Sensors
2.11 20b.3 Throttle potentiometer "952a"
2.12 1.5, 27.1 Ground. Connected to Motronic Box
2.13 1.3 Motronic Box, Pin no: 3
2.14 1.16, 1.17 Ground. Connected to Motronic Box pins 16 and 17
2.15 NC No Connection
2.16 1.24 Motronic Box, Pin no: 24
2.17 1.4, 35, 22.1, 15.1, 38.7 Motronic, Starter relay, Cold Start Timer Switch, Cold Start Injector, Dashboard Connector
2.18 27.2 1. Cylinder ignition wire sensor "987"
2.19 27.3 1. Cylinder ignition wire sensor "987"
2.20 20b.1 Throttle potentiometer shield + ground "952"
2.21 3.1 Connector "B" to automatic transmission
2.22 NC No Connection
2.23 NC No Connection
2.24 1.24 Motronic Box, Pin no: 24
2.25 1.35, 5.4 Motronic Box Pin no: 35, Relay 2 "966"


Knock Sensor Box is connected to intake manifold with a hose.See picture.

No: 3 * BMW Drawing no: B * 4-pin connector between engine and transmission *
Number: Interconnection numbers Connected to: Wire colors:
3.1 2.21 Knock Sensor Box, Pin no: 21 Yellow White
3.2 2.5 Knock Sensor Box, Pin no: 5 White Red
3.3 2.7 Knock Sensor Box, Pin no: 7 White Blue
3.4 1.35 Motronic Box, Pin no: 35 Red Blue
No 4 * BMW Drawing no: A * 3-pin connector between engine and dashboard computer *
Number: Interconnection numbers Connected to: Wire colors:
4.1 1.11 Motronic Box, Pin no: 11 White
4.2 5.2 Relay 2 "966" Green
4.3 1.1, 20.4, 29 Motronic Box, Diagnostics, Ignition Coil Black
No 5 * BMW drawing no: 966 * Relay 2 *
Number: Interconnection numbers Connected to: Wire colors:
5.1 ("30") 39 Battery +12 V Red
5.2 ("86") 4.2 Connector "A" to dashboard computer Green
5.3 ("87") 1.18, 5.4 Motronic Box, Pin no: 18 Red Blue
5.4 ("87") 1.35, 2.25, 5.3 Motronic Box, Knock Sensor Box Red Blue
5.5 ("85") 1.16, 1.17 Motronic Box, ground Brown
5.6 ("87") 6.3, 5.7 Air Pressure Sensor "986" Red White
5.7 ("87") 37.2, 12.2, 13.2, 14.2, 16.2, 24.2, 25.2, 5.6 Relay 1, Injectors 1-6 Red White
No 6 * BMW Drawing no: 986 * Ambient Air Pressure Sensor *
Number: Interconnection numbers Connected to: Wire colors:
6.1 1.5 Motronic Box, ground Brown
6.2 1.30 Motronic Box, voltage input White
6.3 5.6 Relay 2 "966" Red White
No 7* BMW Drawing no: 928* RPM Sensor *
Number: Interconnection numbers Connected to: Wire colors:
7.1 1.27 Motronic Box Yellow
7.2 1.8 Motronic Box Black
7.3 1.23 Motronic Box, shielded ground
No 8 * BMW Drawing no: 929* Crankshaft Position Indicator*
Number: Interconnection numbers Connected to: Wire colors:
8.1 1.25 Motronic Box Yellow
8.2 1.26 Motronic Box Black
8.3 1.5 Motronic Box, shielded ground
No 9* BMW Drawing no: 911* Oil Pressure Sensor*
Number: Interconnection numbers Connected to: Wire colors:
9.1 38.10 Dashboard Connector "900" Brown Green
No 10 * BMW Drawing no: 949* Knock Sensor 2*
Number: Interconnection numbers Connected to: Wire colors:
10.1 2.6 Knock Sensor Box, pin no 6 Black
10.2 2.10 Knock Sensor Box Yellow
10.3 2.10 Shielded ground to pin 10
No 11 * BMW Drawing no: *VDO Sensor*
Number: Interconnection numbers Connected to: Wire colors:
11.1 41.2 VDO connector White Grey
No 12, 13 and 14* BMW Drawing no: 955 *Fuel Injectors 6, 5 and 4* Model 0280 150 200 *
Number: Interconnection numbers Connected to: Wire colors:
12.1, 13.1, 14.1 1.15 Motronic Box, pin no 15 Brown Yellow
12.1, 13.1, 14.1 37.2 Relay 1 "965" Red White
No 15 * BMW Drawing no: 956 * Cold Start Injector*
Number: Interconnection numbers Connected to: Wire colors:
15.1 1.4, 35, 22.1, 2.17, 38.7 Motronic Box, Starter relay, Cold start switch, Knock sensor box, Dashboard connector Black Yellow
15.2 22.2 Cold Start Timer Switch "958" White
No 16, 24 and 25 * BMW Drawing no: 955 * Fuel Injectors 3, 1 and 2 * Model 0280 150 200 *
Number: Interconnection numbers Connected to: Wire colors:
16.1, 24.1, 25.1 1.14 Motronic Box, pin no 14 Brown White
16.2, 24.2, 25.2 37.2 Relay 1 "965" Red White
No 17 * BMW Drawing no: 963 * Supplementary Air Valve*
Number: Interconnection numbers Connected to: Wire colors:
17.1 1.5 Motronic Box, pin 5, ground Brown
17.2 37.4 Relay 1 "965" Green Violet
No 18 * BMW Drawing no: 953 * Intake Airflow Meter/Air Temperature Meter*
Number: Interconnection numbers Connected to: Wire colors:
18.1 1.22 Motronic Box, pin 22 (Temp. Input) Grey Violet
18.2 1.7 Motronic Box, pin 7 (Air Volume Input) Grey Yellow
18.3 1.9 Motronic Box, pin no 9 Grey White
18.4 1.6 Motronic Box, pin no 6 Grey Brown
No 19 * BMW Drawing no: 977 * Turbo Pressure Valve*
Number: Interconnection numbers Connected to: Wire colors:
19.1 28, 38.8 Ignition Coil +, Dashboard Connector Green
19.2 2.2 Knock Sensor Box, pin 2 Green Blue
No 20 * BMW Drawing no: 938 * Diagnostics Socket*
Number: Interconnection numbers Connected to: Wire colors:
20.1 1.4, 35, 22.1, 15.1, 2.17, 38.7, Starter relay, Cold start switch, Cold start injector, Knock sensor box, Dashboard connector, Black Yellow
20.2 21.2 118 C Temperature Sensor, "913" Brown Violet
20.3 32 Generator -, "907" Blue
20.4 29 Ignition Coil - Black
20.5 38.5 Dashboard Connector "900" Green Yellow
20.6 33 Generator +, "907" Red
20.7 1.5 Motronic Box, pin no 5, ground Brown
20.8 38.11 Dashboard Connector "900" White Blue
20.9 Position Indicator "903" Yellow
20.10 Position Indicator "903" Black
20.11 Position Indicator "903", ground shield Black
No 20b * BMW Drawing no's: 952 and 952a * Throttle Switch and Throttle Position*
Number: Interconnection numbers Connected to: Wire colors:
20b.1 (952a) 2.20 Knock Sensor Box, shielded ground Brown
20b.2 (952a) 2.8 Knock Sensor Box, Voltage Input

Green

20b.3 (952a) 2.11 Knock Sensor Box White
20b.4 (952) 1.2 Motronic Box Brown Blue
20b.5 (952) 1.5 Motronic Box ground Brown
Special notes: 20b.1 - 20b.3 are in Throttle Position potentiometer. 20b.4 and 20b.5 are in Throttle Switch. I accidentally assigned two parts (Diagnostics Socket and Throttle assembly) with the same number 20. Therefore I have to use 20 and 20b numbering.
No 21 * BMW Drawing no: 913 * 118 C Temperature Switch*
Number: Interconnection numbers Connected to: Wire colors:
21.1 38.4 Dashboard Connector "900" Brown Grey
21.2 20.2, 38.3 Diagnostics Socket "938", Dashboard C. Brown Violet
No 22 * BMW Drawing no: 958 * Cold Start Timer Switch. Version 8 s./35 C *
Number: Interconnection numbers Connected to: Wire colors:
22.1 1.4, 35, 15.1, 2.17, 38.7, 20.1 Motronic, Starter relay, Cold start injector, Knock sensor box, Dashboard connector, Diagnostics Socket Black Yellow
22.2 15.2 Cold Start Injector "956" White
No 23 * BMW Drawing no: 959 * Motor Temperature sensor *
Number: Interconnection numbers Connected to: Wire colors:
23.1 1.13 Motronic Box Brown Red
23.2 1.5 Motronic Box, ground Brown
No 26 * BMW Drawing no: 949 * Knock Sensor 1 *
Number: Interconnection numbers Connected to: Wire colors:
26.1 2.9 Knock Sensor Box Black
26.2 2.10 Knock Sensor Box, shielded ground Yellow
No 27 * BMW Drawing no: 987 * 1. cylinder Ignition Wire Sensor *
Number: Interconnection numbers Connected to: Wire colors:
27.1 2.12 Knock Sensor Box, ground Brown
27.2 2.18 Knock Sensor Box Yellow
27.3 2.19 Knock Sensor Box Black
No 28, 29, 30 and 31* BMW Drawing no: 902 *Ignition Coil*
Number: Interconnection numbers Connected to: Wire colors:
28 (+) 19.1, 38.8 Turbo Pressure Valve, Dashboard Green
29 (-) 1.1, 4.3, 20.4, 30 Motronic, Connector A, Diagnostics, Black
30 (-) 31, 1.1, 4.3, 20.4, 30 Motronic, Connector A, Diagnostics, Black
31 (-) 30 Black
No 32 and 33 * BMW Drawing no: 907 * Generator *
Number: Interconnection numbers Connected to: Wire colors:
32 20.3, 38.1, 41.1 Diagnostics, Dashboard, VDO Blue
33 (+) 20.6, 34 Diagnostics, Starter + Red
No 34 and 35 * BMW Drawing no: 908 * Starter *
Number: Interconnection numbers Connected to: Wire colors:
34 (+) 40, 33 Battery +, Generator + Red
35 1.4, 22.1, 15.1, 2.17, 38.7, 20.1 Motronic, Cold start switch, Cold start injector, Knock sensor box, Dashboard connector, Diagnostics Socket Black Yellow
No 36 * BMW Drawing no: 912 * Oil Level Sensor (in the bottom of the engine)*
Number: Interconnection numbers Connected to: Wire colors:
36.1 38.2 Dashboard Connector "900" Blue Violet
36.2 38.9 Dashboard Connector "900" White
No 37 * BMW Drawing no: 965 * Relay 1 (on fuse box cover)*
Number: Interconnection numbers Connected to: Wire colors:
37.1 ("30") 40 Battery + Red
37.2 ("86") 5.7, 12.2, 13.2, 14.2, 16.2, 24.2, 25.2 Relay 2, Injectors 1-6 Red White
37.3 ("85") 1.20 Motronic Box, pin no 20 Brown Green
37.4 ("87") 17.2, 37.5 Supplementary Air Valve, Dashboard Green Violet
37.5 ("87") 38.6, 37.4 Dashboard Connector "900" Green Violet
No 38 * BMW Drawing no: 900 * Dashboard Connector *
Number: Interconnection numbers Connected to: Wire colors:
38.1 32 Generator - Blue
38.2 36.1 Oil Level Sensor "912" Blue Violet
38.3 21.2 118 C Temp. Switch "913" Brown Violet
38.4 21.1 118 C Temp. Switch "913" Brown Grey
38.5 20.5 Diagnostics "938" Green Yellow
38.6 37.5 Relay 1 Green Violet
38.7 1.4, 35, 22.1, 15.1, 2.17, 20.1 Motronic, Starter relay, Cold start switch, Cold start injector, Knock sensor box, Diagnostics Socket Black Yellow
38.8 28, 19.1 Ignition Coil, Turbo Pressure Valve Green
38.9 36.2 Oil Level Sensor "912" White
38.10 9 Oil Pressure Sensor Green Brown
38.11 20.8 Diagnostics "938" White Blue
No 39 and 40 * BMW Drawing no: 23* Battery *
Number: Interconnection numbers Connected to: Wire colors:
39 1.5, 1.16, 1.17, 2.12 Motronic Box, Knock Box, main ground Brown
40 37.1, 5.1 Relay 1"965", Relay 2 "966", main +12V Red
No 41* BMW Drawing no: N/A * VDO Connector*
Number: Interconnection numbers Connected to: Wire colors:
41.1 32 Generator -, "907" Blue
41.2 11 VDO Sensor White Grey