Help with scanned error codes

[kiev]

Looks like it is on pin 7 (K-line) of the OBDII port, from the FSM

 

[tomhanman]

Thanks to both of you.

I don't really understand the half chip full chip nonsense. My adaptor was sold as full chip over ten years ago, but on opening it, that is clearly not the case! But it gives a "full chip" code to diagbox, so it works, but I guess just fails on certain tasks, maybe like airbag fault resets. Why do they keep making both variants when the price difference in components is cents?

Thanks for the direction towards capacity reset. I'll remember that.

2.2 Ohm came from the Internet. I'm not sure it's reliable. But I was just about to invest in the little black boxes sold on Aliexpress that plug in in place of an airbag and make the srs unit think the airbag is all good. They're cheap and pretty common. But as always, before getting over excited with cool things I find on AliExpress, I googled them and quickly discovered they're a black box with a 2.2 Ohm resistor inside! So I just went to my resistor drawer and problem potentially solved. There is some debate about the resistance of the pretensionners being potentially higher. I'll try unplugging some things today as hj... suggested and see if I get new codes, and see if I can remove them.

I have a suspicion that the unit is now basically locked up as it has flagged those two indelible faults that can only be removed by accessing the chip directly. The imiev manual says the only solution after these codes is replacement with new unit, so I would be surprised if they could just erase them with their software. But I have been surprised before!

I will definitely be looking into the srs-car communication, but Can and coding is a whole new frontier for me. (I did code in bbc basic when I was 10) I've been hovering around can and arduino for years, even bought a couple with can boards but nothing more!

Even if it were possible I'd need the system fully functional to sniff the canbus and find the happy messages to spoof. So I need to resolve the srs unit repair/replacement.

Does anyone know if the unit is coded to the car? That is the big question. If not I can get one used, otherwise I need mine reset.

I'll report back. Cheers,
Tom.

 

[tomhanman]

Indeed it does Kiev, that's outside of the standard obd2 protocol I think, and only available to dedicated units like the oem diagbox unit (and maybe fullchip clone) and mut3 etc. I don't know if the MX+ unit can do that, it certainly claims extra protocol abilities.

 

[MickeyS70]

I have a suspicion that the unit is now basically locked up as it has flagged those two indelible faults that can only be removed by accessing the chip directly. The imiev manual says the only solution after these codes is replacement with new unit, so I would be surprised if they could just erase them with their software. But I have been surprised before!

According to @hjdlsnbc it’s possible to clear these faults with original VCI’s?

I will definitely be looking into the srs-car communication, but Can and coding is a whole new frontier for me. (I did code in bbc basic when I was 10) I've been hovering around can and arduino for years, even bought a couple with can boards but nothing more!

Looks like it’s done via K-Line comms, CAN bridge won’t help here, unfortunately.

Does anyone know if the unit is coded to the car? That is the big question. If not I can get one used, otherwise I need mine reset.

Afaik SRS ECU isn’t VIN coded.

 

[tomhanman]

hj... didn't mention exactly which fault codes he has cleared and from where. I have just unplugged the SRS unit completely from the car, and with the diagbox I have successfully removed the B1499 and B1698 codes from the EV_ecu. However, two new codes U1805 and U1802 replace them complaining of com problems with the SRS unit (fair enough )

Unfortunately it still won't go into ready, or charge. BUT it does initiate charging, I hear the fans, and contactors, but the charge icon flashes and then goes out. I'm super happy to hear the contactors for the first time, it feels so close (and yet so far).

If SRS really isn't coded at all, then any used part would do (from a non accident damaged car), but that sounds too easy!

 

[tomhanman]

As suggested I've unplugged the G sensor, I also took the opportunity to unplug an airbag replacement resistor, and one of the side impact sensors.

Unsurprisingly the SRS unit shows three more fault codes.

These have no effect elsewhere and only show up in that ecu. I cannot clear them (which makes sense as they are active).

And when I reconnect them, the SRS unit clears them automatically without any intervention from me. So it goes back to showing the faults from before, and not complaining about any missing sensors or airbags... a very nice confirmation that the 2.2 Ohm resistors are indeed all that is required to replace an airbag!!!

 

[martinwinlow]

Why should someone want to spend about 80$ on OBDLink LX and about 20$ on Hobdrive just to get Hobdrive working? This is a cost of about 100$ for a fraction of the functionality of what you can get with MUT3-SE or Diagbox. Getting MUT3-SE and Diagbox working cost each less then 100$.
With original quality adapters it cost more, but it is also by far more worth it then spending that much money for some third party software named Hobdrive
Here the overview:
https://myimiev.com/threads/overvie...ters-their-functionality-and-the-future.5719/

Well, Hobdrive is a much simpler interface than MUT3-SE and, in my experience, what Hobdrive gives you is generally all that's needed to fix the common issues on these cars. MUT3-SE is pretty awful in terms of user-friendliness. It is also very slow - but that may be more down the the old laptop I use than anything.

 

[kiev]

The K-line is just another serial buss protocol. Started looking into it awhile back but didn't have any need at the time.

One approach might be to trace out the circuits in the SRS unit and look for an eeprom to read out contents. It could just be a crash flag that sets some bits, or more complicated and destructive flag that disables a circuit completely. For legal liability reasons i could see a reason they might completely disable it. It might be like a flight data recorder in an airplane.

Nothing to lose by looking in there.

 

[tomhanman]

Kiev, that is exactly what happens - something stored in an eeprom that just keeps the srs unit sending out the same error code endlessly to the vehicle ecu so it won't start.

I've nothing to lose by looking inside except my dignity! I wouldn't know where to start with trying to dump and then mod and then flash an eeprom.

I've found an online company offering a reset of the unit for 100€. Surely worth that, so it's going in a box this evening and away. So no more diag until.next week... which is good because I've got to build my kid's Christmas present which, to my untrained eye, does not look nearly finished!

 

[tomhanman]

Ok, couldn't resist before sending it!

 

[hjdlsnbc]

Well, Hobdrive is a much simpler interface than MUT3-SE and, in my experience, what Hobdrive gives you is generally all that's needed to fix the common issues on these cars. MUT3-SE is pretty awful in terms of user-friendliness. It is also very slow - but that may be more down the the old laptop I use than anything.

Then write to the people in need of help that the most cheap and functional tool is MUT3 SE. And if they have problems understanding MUT3 SE, do not like the design or its speed, then they could spend more money for other tools that have less functionality.

I wouldn't know where to start with trying to dump and then mod and then flash an eeprom.

This would be awesome if you could do that research and tell everyone how this could be done.

 

[kiev]

Ok, couldn't resist before sending it!

If you can read the marking on the 3 little 8-pin chips on the board--one of those could be eeprom

Is that white connector visible from outside of the closed unit, or only with the cover removed?

Likely candidate eeprom marked here

 

[tomhanman]

Yep, I think you're right Kiev. From.all the videos of other srs modules being reset it looks the right choice.

But I would need to buy gear and get it right first time, and there's too much to lose, with little to gain I'm afraid.

The only things accessible from outside the case are the other side of the yellow connectors. If you're meaning the white thing with 25281 written on it, then it's not a connector. Some sort of roll over sensor maybe?

 

[kiev]

When an accident occurs, the SRS airbag control module stores information from the event in the form of crash data and hard codes. Everything from the vehicle speed, throttle position, engine speed, and brake light switch position is recorded. The unit may also pick up seat belt pre-tensioner deployments, airbag deployments, seat belt use, and impact speed change. As you can imagine, that can go a long way in painting the picture of an accident scene...

police and investigators can extract the information from the car’s on-board diagnostic port. On a side note, the diagnostic port is what mechanics use to check what is wrong with a car, whether or not a car still has power, and the like. Once the investigators lay hands on this information, they can then proceed in printing out a report on it. When the data is good, it can help test the truth of eyewitness statements obtained at the scene of the accident.

i found pictures of other SRS boards and see a large capacitor and the white module. The cap likely provides the energy to write the data after a crash; maybe the white module is the storage device?