1.9 Mi16 Fault Codes

[sale_gti6 2 1 Cars]

Hi!

 

K-light is sometimes turn on when I driving my '89 405 Mi16. Its on for a few minutes and turn of. No engine power, I have done diagnostic with some wires, grounding pin no 2 on diagnostic socket and I read the following codes: 51 (oxygen sensor), 52 (mixture regulation), 31 (mixture regulation auto-adaptation, 13 (inlet air termistor)

 

Now,question is,what to do? Changing oxygen sensor? Air flow meter problem? Or ... ?

[jackherer 543]

The inlet air temp sensor fault code would make me look at the air flow meter plug and wiring as well as the sensor itself although they are usually OK. Measure the resistance of the sensor on the AFM itself to check it's within a sensible range then check the resistance across the relevant pins on the ECU plug.

[sale_gti6 2 1 Cars]

Problem solved! Oxygen sensor changed and ecu restarted. now pug run good...

[jackherer 543]

Nice one! Did that clear all the fault codes?

[sale_gti6 2 1 Cars]

Yes,but after 5-6 days I have done diagnostic again and now is fault no.13 (inlet air termistor).

[jackherer 543]

Do this:

Measure the resistance of the sensor on the AFM itself to check it's within a sensible range then check the resistance across the relevant pins on the ECU plug.

Also check the condition of the AFM plug including the individual pins and under the rubber boot if it has one.

[sale_gti6 2 1 Cars]

I'll check that in a few days...

[jackherer 543]

Let us know how you get on!

[sale_gti6 2 1 Cars]

Of course,I'll let you know what happens

[sale_gti6 2 1 Cars]

So,I had a few air flow meter and only one was with good air temperature termistor. When I replaced the AFM, I tried the car and do diagnostic again. Now is everiting ok. Diagnostic showed code 12 for start of diagnostic,and code 11 for end of diagnostic. Pug now runs better. Throttle response is better.

[jackherer 543]

That's unusual, they are normally fairly reliable. Have you tested them with a multimeter or just let the ECU diagnose them? It would be interesting to know how they have failed, open circuit, short circuit, low resistance, high resistance etc and if they have all failed in the same way?

[sale_gti6 2 1 Cars]

I have 4 AFM. On one was damaged tape and I have not instaled that AFM, on 2nd was physically damaged temperature termistor, 3rd I've tested was correct and I have not tried the 4th (perhaps working).

I did not test it because I did not have a multimeter,but I can do that in the next few days.