Opel Agila B 2012 ESP fault

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Opel Agila B 2012 ESP fault

Postby liviu2004 » Sat Nov 04, 2017 10:32 am

This car came in a garage for a clutch change. In order to get to it, also the steering gear has to go away. Job was done, however, Owner came back that the steering wheel had a bit of play. Mechanic had to refit the steering wheel shaft and immediately after that, ESP light came on.

Faultcodes reading resulted with:
- C1076 brake pressure sensor not calibrated
- C1075 steering wheel angle sensor not calibrated
- C1078 yaw rate sensor not calibrated
- C1024 steering wheel angle sensor circuit malfunction.

Tries to calibrate the sensors failed.

I was asked in to help, got this picture in.

esp faults.png


Normally there is no much I can do in such cases, maybe if I am lucky I can find a fault in wiring, however, I have no spare parts. So reluctantly went there, using the opel tools I couldn't get the sensors calibrated. Which is kind of normal, as long as system complains of a malfunction. Odd was, in Data List, brake pressure sensor showed something like 256 bars, acceleration rate 2.5m/s-2, steering angle sensor 0 degrees, all fixed values.

Now, this sensor connector is very simple, it contains 4 wires, plus, minus, and 2 for canbus. And soon after, power supply was confirmed as good.

Canbus resistance was ok, 61.2 ohms.

I was left with no other choice than take the Pico out and scope the canbus. Not sure what I hoped to see but this is what it showed up.

canbus 3.5.png


Not long after, something caught the corner of my eye, so went back in captures and what would that be?

canbus what 2.png


canbus what.png


Something like a canbus message but the voltage levels are not where I expected to be. I kind of thought, this might be our steering angle sensor sending faulty messages, but how can I prove it comes from it?

One way to do it, remove the plug and scope the remaining part of the canbus, and yes, no such messages came on.
A bit odd that sometimes the voltage levels went up/down to 3.8V / 0.7V.

canbus 3.8.png


So I could not do more than that, and recommended the garage to replace the sensor.
Which they did one day later and I was relieved when they said the errors were gone.

This is the sensor and I am going to receive it Tuesday, for a closer look.

IMG_2817.JPG

IMG_2818.JPG

IMG_2819.JPG
liviu2004
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Re: Opel Agila B 2012 ESP fault

Postby Tronic » Sat Nov 04, 2017 4:36 pm

Well done liviu2004 and thanks for sharing!

Interesting reading about your thoughts and what you did to solve the fault. If you do not mind, could you please take some closer pictures on the board when you get the sensor on Tuesday. If components on the other side, that one as well. It is always interesting to look what is inside. I have a bad habit to open everything in order to see if there is something that can be done and of course out of curiosity :lol:
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Re: Opel Agila B 2012 ESP fault

Postby liviu2004 » Sun Dec 31, 2017 12:16 am

I got the sensor, had a close look on the chips, they are masked. No sign of damage nor bad soldering. Went with the heat gun over it but did not improved. Scoped the sensor over 60 ohms network and got a really bad image, my other laptop is off now but I will post a picture. This part goes to the garbage, actually I am going to split the plastic from the electronics and give it to the recycling place we have here in the village.
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