ECU connector missing contacts

[Derptastic]

While trying to diagnose a problem with rough idle I decided to perform some electrical tests to check my ICV and AFM. Checking the AFM involves measuring resistance between pins 7 and 9 on the ECU connector (according to my bentley manual)... problem is there is no contact present on pin 9.

Has anyone seen this before? How do I perform an electrical test on the AFM?

[spdracrm3]

sometimes difficult to tell which side of the connector they are referring to (face or backprobing ) so i like to find the wires by color to be sure im testing the right wires. look up in ETM (also confirm ECU pin #s at that time) then remove back cover on ECU connector and look for those wires by color

[whodwho]

There is nothing designated for that pin

The AFM related pins are:

7- Signal
12 - 5v Ref
26 - Ground

[Gregs///M]

You will not sufficiently verify the AFM is ok without an oscilloscope when measuring that signal. Simply because a DMM acquires data and displays and average, while an o-scope measures true signal and is plotted over time. O-scopes are also high freq devices so any errors or voltage drops in the milliseconds will be captured, however a DMM will not be able to.

[Derptastic]

Thank you all for the info. I do have an oscilloscope but I don't have enough reason to suspect the AFM is contributing to my problems. I was thinking it would be an easy test like the ICV.

[JohnH]

You are using a 35 pin motronic 1.0 pinout chart against a 55 pin motronic 1.1/1.3 connector.

See http://e30zone.net/e30zonewiki/index.php/ECU_Pinouts

[jlevie]

The Bentley is wrong. Pin 26 is the AFM common, pin 7 is the air flow input, pin 12 is the reference output, and pin 46 is the intake air temperature input.