Volvo vnl Multiple ecm's problems out of nowhere

Just did, i checked them out with ohmmeter I have sound out of all green yellow and white wires, one set has green yellow and white wires going in to the black jacket, and other green yellow alone going into the back jacket.

 

Hmmmm..........

 

In situation like this i suggest, first at the diagnostic connector 9 pins like you probably already did with the ignition at OFF position check the resistance value between pin cavity C and D you should have approx 60 ohms.
If the resistance value is OK, turn the ignition at ON position and check the voltage (DC) between pin A (center) and pin C of the diagnostic connector.
value expected 2.3 - 2.6 volts and voltage reading should change all the time look if the graph bar is moving on your multimeter.
Do the same test with the pin A and D 2.6 up to 2.9 volts and graph bar should move all the time.
If you see steady voltage or high or Low voltage on your data link circuit, keep your multimeter installed on the diagnostic connector and unplug the ecus one at the time and monitor your Data Link voltage.
It's a easy way to figure out if a ECU is Defective.
Ben

 

Hi Ben. Yes I did that, and to be honest with you i totally forgot about it that something was going on with voltage, it wasn't like it should be, I'll recheck tomorrow in the morning . Thank you for reminding that to me. Thanks Andy

 

Hi Andy, i saw different situation about Data Link circuit in my back ground, i saw 8.5 volts in both data link circuit or freezing (Steady) reading, but the way i explained to you is the way we used since many years and it's the best that i know, even though it's not always the OEM recommandation. . ..
Keep me in touch with you results.
Thanks
Ben

 

I sure will, thank you sir. Andy

 

Hello again. Ok here is what I came up with.
With everything connected, key off position
Between pins C D 34.4 34.3 34.2 ohms fluctuates
Again key off position 1 resistor removed by the engine 66.4 66.3 66.2 ohms again fluctuates
Key off battery disconnected everything else connected 59.7 ohms
Key off battery connected ,that little plug black wires on one end of the plug green yellow wires on other plug disconnected 59.4 ohms + -1ohm

Voltage readings:
Key on position everything connected
C A pins = 0.02 volts
D A pins = 0.06 volts
Key on position that same wire disconnected
C A pins =2.54 - 2.57 volts
D A pins =2.36 - 2.38 volts
I believe that wire that I'm disconnecting is for brake ecu. Not sure 100 percent. Any suggestions on this. Thanks Andy

 

Brake ECU disconnected still same voltage in the zeros. 0.04 or so, but if I disconnected shifter it would be 2.55- 2.56 volts on pins C A

 

Hi Andy, it look like your shifter stay energized for a reason that i don't know .
We cannot take a resistance value on a circuit if voltage is present in that circuit.
Suggestion, disconnect the shifter plug, use the cluster menu and erase all fault code, check which code will come back except code involving shifter MID 130 i think.
Ben

 

Hello Ben.
With all wiring intact dash information showing
Engine ecu, brake ecu,light control module, vehicle ECU and codes shown are:
Engine ecu
Mid128 sid231 fmi9
Mid128 pid84 fmi2
Trans ecu (sometimes active sometimesinactive)
Mid130 sid231 fmi2
Brake ECU
Mid136 sid231 fmi6
Mid136 sid231 fmi6
Vehicle ECU
Mid144 sid231 fmi2
Mid144 pid84 fmi2
Mid144 psid200 fmi9
Mid144 psid205 fmi9

With that green yellow wires disconnect at the batt. box codes are
Engine ecu
Mid128 pid84 fmi2
Trans ecu again sometimes active sometimesinactive
Mid130 sid231 fmi2
Vehicle ecu
Mid144 pid84 fmi2
Mid144 psid205 fmi9
I believe if I disconnect the shifter it's the same as I would disconnect that wire by battery box.