I am troubleshooting a fault 1-4-4 on my 89 240 wagon. My Bentlely manual does not show the complete plug pin outs for either the ecm or icm plugs. The ICM has numbers inside the plug cavity,but the ecm (ignition) does not. I found an excellent post by Pierce from June 2013,on how to troubleshoot, but am frustrated not finding a complete plug pin out. I found pin 8 by probing every pin in the plug and do have continuity from pin 8in the ecm to pin 25 in icu.
I found the fuses corroded,and cleaned them. I also ordered the gold /ceramic fuses,and a new fuel relay from IPD,as some previous posts pointed in that direction. This car has 302 K miles,and the original fuel relay.

 

LH2.4 ECU:
1 - brown - to ICU pin 17
2 - yellow white - to ICU pin 7 and throttle idle switch
3 - blue-white - to full throttle switch
4 - red - always on power
5 - brown-black - ground
6 - green-yellow to MAF pin 2
7 - red-white to MAF pin 3
8 - white to MAF pin 4
9 - orange - switched power from fuel pump relay
10 - NC
11 - NC
12 - green-black to diagnostic box socket 2
13 - blue-red to coolant temp sensor
14 - green to AC pressure switch
15 - grey-red from AC relay
16 - NC
17 - black - main ground
18 - green-white - injector control
19 - brown-black - option jumpers
20 - blue-green - control to fuel pump relay
21 - yellow-black - control to fuel injection relay
22 - pink-white - to ICU pin 3
23 - NC
24 - green - signal from O2 sensor
25 - yellow-brown to ICU pin 8
26 - violet - shift indicator light (manual gearbox only)
27 - NC
28 - brown-white to ICU pin 4
29 - black to option jumper
30 - blue-yellow from ignition switch starter contact
31 - NC
32 - white/black to cold start injector
33 - green-red to idle air control
34 - blue-black from speedo signal
35 - blue from ignition switch 'run'.


EZ-116K ICU:
1 - white to diagnostic controller socket 6
2 - blue-red from coolant temp sensor
3 - pink-white to ECU pin 22
4 - brown-white to ECU pin 28
5 - red - unswitched power
6 - blue - ignition switched power on run
7 - yellow-white from full throttle switch
8 - yellow-brown from ECU pin 25
9 - NC
10 - blue-yellow - signal from crank position sensor (CPS)
11 - black shield ground from CPS
12 - black ground to knock sensor
13 - green signal from knock sensor
14 - black ground for California EGR
15 - white-black signal to EGR
16 - grey to ignition power module
17 - brown to ECU pin 1
18 - NC
19 - NC
20 - brown-black - ground
21 - NC
22 - violet for EGR temp sensor
23 - red-yellow - signal from CPS

the wire colors are from a 1991, as my 1989 scan is too fuzzy to read, should be close enough. pinouts are the same for all LH2.4/EZ116K systems, although not all pins are always used.

 

Sticky information Pierce. Will help quite a few others I think. Plus you dont have to type it every time

 

Thank you pierce ! The bentley manual is a good manual,but the diagram information is fragmented.