Where and how to access ECU: I have tried to illustrate where and how to access the ECU, it is in the glove box compartment. To access it open your glove box and undo the two screws holding the plastic cover that is at the “ceiling” of the glove box compartment, under there you will find the ECU and the Connector.
Interesting fact: The 153 Motronic 1.1 ECU is directly swappable (without any modification or otherwise) with all motronic 1.3 ECU’s. The Grey label 173 is the most popular of the 1.3 ecu’s, mainly because of its availability. Generally speaking there is no advantages to running one 1.3 ECU over another. The differences between the 1.1 and 1.3 apart from software updates is that the 1.3 uses only 1 board within the ECU whereas the 1.1 uses two boards. Having less boards means less failure points. Some people have claimed to have better idle with the 1.3 ECU’s although I haven’t noticed such improvements. As I have covered in another article the main benefit to the 1.3 ECU’s is that they are able to store engine fault codes and you do not need a scanner to access them, all you need to do is preform a stomp test. Click “this” to access the stomp test page.
The Motronic 1.0 ECU (325, 325e)
| Pin | Function | Pin | Function | Image |
|---|---|---|---|---|
| 1 | Ignition coil output | 19 | Ground |  |
| 2 | Idle switch | 20 | Main relay | |
| 3 | WOT switch | 21 | Tachometer | |
| 4 | Cranking signal | 22 | AFM Temp sensor | |
| 5 | Ground/Crank PosS Gnd | 23 | Inlet Air Temp/Crank SpS Gnd | |
| 6 | AFM ground | 24 | O2 sensor signal * | |
| 7 | AFM signal | 25 | Crank position sensor 1 | |
| 8 | Crank speed sensor 1 | 26 | Crank position sensor 2 | |
| 9 | AFM supply | 27 | Crank speed sensor 2 | |
| 10 | Auto only special | 28 | Water Pressure switch | |
| 11 | Fuel consumption gauge | 29 | A/C switch (if installed) | |
| 12 | 30 | +Inlet Air Temp | ||
| 13 | Water Temp | 31 | ||
| 14 | Injector output cyl 3&4 | 32 | ||
| 15 | Injector output cyl 1&2 | 33 | ICV pulse | |
| 16 | Ground | 34 | ICV pulse | |
| 17 | Ground | 35 | Injector ground | |
| 18 |
Motronic 1.1 (325i, 325is, 325ix) Green label 153 ECU.
| Pin | Function | Pin | Function | Pin | Function | Image |
|---|---|---|---|---|---|---|
| 1 | Timing Control – to coil and O2 sensor | 20 | 38 |  |
||
| 2 | Ground | 21 | 39 | Programming voltage – Diagnostic Plug | ||
| 3 | Fuel pump relay control | 22 | Idle speed control | 40 | A/C on input | |
| 4 | Idle speed control | 23 | O2 sensor heater | 41 | ||
| 5 | Evaporative purge valve | 24 | Ground | 42 | Park/ neutral input (auto only) | |
| 6 | Engine Speed output- to instrument cluster | 25 | 43 | |||
| 7 | AFM input – pin 2 | 26 | AFM common- ground pin 4 | 44 | AFM air inlet temp- pin 1 | |
| 8 | Cylinder ID sensor input | 27 | Start input- to ignition switch and coil | 45 | Coolant Temp input | |
| 9 | 28 | O2 input | 46 | |||
| 10 | O2 sensor ground | 29 | 47 | Engine speed input | ||
| 11 | 30 | 48 | Engine speed input | |||
| 12 | AFM reference output- pin 3 | 31 | Cylinder ID sensor input | 49 | ||
| 13 | RXO – diagnostic plug | 32 | Econometer | 50 | ||
| 14 | Ground | 33 | 51 | |||
| 15 | Check engine light – to cluster | 34 | 52 | Closed throttle input – pin 1 | ||
| 16 | Injectors 1,3,5 | 35 | 53 | WOT input – pin 3Note: TPS pin 2 is ground | ||
| 17 | Injectors 2,4,6 | 36 | Main relay | 54 | ||
| 18 | Power input main relay | 37 | Power input – to main relay | 55 | TXD – diagnostic plug | |
| 19 | Ground |
Motronic 1.3 (325i, 325is, 325ix) later model 173 grey label ECU and others (351, 380, 382, 524, 525, 526)
| Pin | Colour | Function | Pin | Colour | Function | Pin | Colour | Function | Image |
|---|---|---|---|---|---|---|---|---|---|
| 1 | BK | Timing Control – to coil and O2 sensor | 20 | 38 | ABS and OBC cutoff for Injectors |  |
|||
| 2 | BR | Ground | 21 | 39 | GN/BU | Programming voltage – Diagnostic Plug | |||
| 3 | BR/GN | Fuel pump relay control | 22 | WT/GN | Idle speed Close control | 40 | BK/GY | A/C low pressure cutoff | |
| 4 | WT/YL | Idle speed control | 23 | BR/GR | O2 sensor heater | 41 | VI/GY | A/C On input | |
| 5 | BR | Evaporative purge valve | 24 | BR | Ground | 42 | RD/BU | Park/ neutral input (auto only) | |
| 6 | BK | Tachometer | 25 | 43 | |||||
| 7 | GY/YL | AFM input – pin 2 | 26 | GY/BU | AFM common- ground pin 4 | 44 | GY/VI | AFM air inlet temp- pin 1 | |
| 8 | BL | Cylinder ID sensor input | 27 | GN | Start input- to ignition switch and coil from OBC | 45 | BR/RD | Coolant Temp input | |
| 9 | 28 | BK | O2 input | 46 | |||||
| 10 | YL | O2 sensor ground | 29 | BK/WT | Vehicle Speed input frominstrument cluster | 47 | BL | Engine speed input | |
| 11 | 30 | 48 | YL | Engine speed input | |||||
| 12 | GY/WT | AFM reference output- pin 3 | 31 | YL | Cylinder ID sensor input | 49 | |||
| 13 | WT/YL | RXO – diagnostic plug | 32 | WT/BL | Econometer | 50 | ABS Deceleration Fuel Cut-Off Overide | ||
| 14 | BR | Injector Ground | 33 | 51 | Auto Kick-Down Switch input | ||||
| 15 | GY | Check engine light – to cluster | 34 | 52 | BR/BL | Closed throttle input – pin 1 | |||
| 16 | BR/WT | Injectors 1,3,5 | 35 | 53 | BR/BL | WOT input – pin 3Note: TPS pin 2 is ground | |||
| 17 | BR/YL | Injectors 2,4,6 | 36 | BR | Main relay output | 54 | Automatic Transmission Torque Converter Lock-up Switch | ||
| 18 | RD | Constant 12V fromBattery | 37 | RD/BU | Switched power from main relay | 55 | WT/VI | TXD – diagnostic plug | |
| 19 | BR/OR | Main Ground |
ECU electrical tests (at the connector)
35 pin (325, 325e)
55pin (325i, 325is, 325ix)
List of 6 cylinder E30 ECU’s
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 153
Bosch Motronic M1.1
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 173
Bosch Motronic M1.3
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 351
Bosch Motronic M1.3
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 380
Bosch Motronic M1.3
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 382
Bosch Motronic M1.3
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 524
Bosch Motronic M1.3
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 525
Bosch Motronic M1.3
325i/is/iX
E30
M20/B25 (170hp)
87-91
0 261 200 526
Bosch Motronic M1.3
325e/es
E30
M20/B27 (122hp)
9/84-12/86
0 261 200 027
Bosch Motronic Basic M1.0
325e/es
E30
M20/B27 (127hp)
1/87-9/87
0 261 200 154
Bosch Motronic M1.1
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[…] fuer die M3.3 beim E32 M60 hab ich noch nichts gefunden, aber M3.3 fuer den S50B30 mit Vanos EndTuning – BMW Pinouts sollte helfen auch fuer den M60 Bosch Motronic M1.1 und 1.3 ECU Pinout and Electrical tests E30 | RTS – Your Total BMW Enthusiast […]
Hi, I have a #173 ECU and I think the last owner may have modified the chip. Is there a way that I can bench test my ECU to find out the chip modifications.
Thanks
F
The best way to check is to open the casing and look at the chip itself, it will be labeled as an aftermarket chip by the maker.
[…] hat (siehe mein Kommentar im E34 Forum). Aber hier noch mal das Pinout the M1.1 und M1.3 ECU Pinout and Electrical tests E30 | RTS – Your Total BMW Enthusiast __________________ Gruss/Erich 7er Reparaturhilfen Unser Hilfsprojekt […]
please could you supply me pin out for connector for e34 525 m50 motor19 92 that I have fitted to a e34 525 1989 m20 motor which had single cam motor in I have both cars complete would really appreciate your help let me know how much
Hola, me presento soy hector y tengo un e30 1987 316, y le hice un swap de motor de m10 a m20b20 1989, y la ecu es una bosch motronic 1.3 0 261 200 172
la pregunta es: puedo ver los códigos de la misma manera?
Hi
Do you have the pin function image for a Bosch Jetronic ECU 0-280-000-328. Please reply. Thanks in advance!
Dirk
just wondering if anyone could help, I have E30 bmw320 1989 looking for L-Jetronic ECU pinout test details.
many thanks
Hello !
I just read your excellent article above about different versions of Motronic ECUs (1.0/1.1/1.3). It is by far the best I have found after done really a lot of fact searching of the ECU issue.
However, I am still missing one very important piece of information.
QUESTION: I have a BMW E30 325i produced in Germany for the European market 18.09.1986. VIN WBAAE410500911143. Engine M20B25 171 hp.
Could you please kindly answer whether the right ECU version for my car is the Motronic 1.0 or 1.1 ? I am the second owner of the “mint condition” car driven 135.000 km only. The original ECU went broke and was replaced with a new 1.0 which I suspect may not be the right version.
Your car can use M 1.1 or M1.3; run ECU ending in 153 (M 1.1) or 173, 380, 525, (M 1.3).
Hello and Happy New Year !
Thank you very much for your kind answer above stating that my BMW should use M 1.1 or M 1.3. However, there is now a mystery that bothers me:
I checked after your answer January 1,2022 what ECU was istalled years ago to the car because the original had went broken. There is M 1.0 (Bosch 026 120081) with 35 pins and two similar sensors (CPS and reference)in the cover of the gearbox which was the M 1.0 set-up.
QUESTION: How it is possible that my BMW runs with M 1.0 and should I replace it with M 1.1 or 1.3 at the earliest opportunity ?
With my very Best Regards,
Pekka
p.s. How can apply for a membership in this rtsauto.com forum ?