V1 Back at it - maf sensor / among few others

[Batmonkey]

Mouser has the plugs for a Cobalt, but a auto recycle yard would be cheaper.
If you clean the ecm connector you sometimes can find a manufacturer name or part number in small print in the plastic casting. The BCM plug is made by Aptiv (Delphi).
AllData will also tell you some info about the connector, here is the BCM C2 plug, which is a 72-pin, using F Micro pins, size 64, and in Grey color plastic.

I was reviewing some of your tests from an old post. I checked resistance from pin 6 and 14, with key off was getting 115 ohms. When I unplugged the power steering connector it went to multimeter went to 1.

(Chat gpt said measure the resistance between pin 6 and 14 then disconnect connectors one at a time and see if there is a change)

 

[Ross]

Unplugging the power steering shouldn't cause the Canbus wires (pin 6 and 14) to short out (1 ohms).
Does your meter read 1 when the wires aren't touching anything?

You should be getting 60 Ohms from pin 6 and 14 of the OBDii port.
Unplugging the power steering should change the resistance from 60 ohms to 120 ohms... or maybe 60 ohms to infinity ohms (no connection), depending how it is wired.
There is a 120 Ohm resistor inside the Power Steering, and another inside the PCM (or ECM or ECU. Depends what you call it).
Basically it is OBDii port goes to the Power Steering, then the BCM, then the PCM. Some cars have a TCM in there too.

 

[Gtstorey]

I don’t think AI is anywhere near to being the place to get automotive repair advice. It’s a a compilation of general advice and you need the particulars for your vehicle.

 

[Gtstorey]

This does a pretty good job of explaining the GM data network as it relates to our vintage GM. Even then it isn't perfect and you need to refer to the wiring diagrams for your particular donor.
https://resources.aeswave.com/ATG-05_Network-Diagnostics-and-Module-Programming.pdf

 

[Batmonkey]

Unplugging the power steering shouldn't cause the Canbus wires (pin 6 and 14) to short out (1 ohms).
Does your meter read 1 when the wires aren't touching anything?

You should be getting 60 Ohms from pin 6 and 14 of the OBDii port.
Unplugging the power steering should change the resistance from 60 ohms to 120 ohms... or maybe 60 ohms to infinity ohms (no connection), depending how it is wired.
There is a 120 Ohm resistor inside the Power Steering, and another inside the PCM (or ECM or ECU. Depends what you call it).
Basically it is OBDii port goes to the Power Steering, then the BCM, then the PCM. Some cars have a TCM in there too.

Yes it reads 1 when its not touching anything

 

[Ross]

Yes it reads 1 when its not touching anything

Okay. So that is the way your meter reports infinity ohms.
Did you have the wiring harness attached to the BCM, ECU, Power Steering computers? Basically plugged into everything?

Measuring 115 ohms when all the wires are plugged in means that you are measuring one of the resistors in your car, and not both of them. Power Steering has one, and another inside the PCM (or ECM or ECU. Depends what you call it).

 

[Batmonkey]

Okay. So that is the way your meter reports infinity ohms.
Did you have the wiring harness attached to the BCM, ECU, Power Steering computers? Basically plugged into everything?

Measuring 115 ohms when all the wires are plugged in means that you are measuring one of the resistors in your car, and not both of them. Power Steering has one, and another inside the PCM (or ECM or ECU. Depends what you call it).

Yeah was around 118/119 actually just checked again with everything plugged.

 

[Gtstorey]

If you are getting 120ohms (approx) with the eps plugged in (x2 data wire plug, not the x1 power plug) then you are reading 1 of the resistors only. Check resistance on pins 4 & 5 of eps x2 connector (disconnected) to see if it reads the ecm resistor (still 120 ohms).

Are you looking at wiring diagrams for this stuff? Here is the path for the data wires. This includes the trans control module. If manual, it just jumps over it.
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