Car throwing error codes and goes into limp mode

[Yehia23]

Can anyone interpret the video above taking into consideration the following.

• Car throwing codes P0700 and U122 on torque
• When i put it on diagnostics scanner at the workshop it found more than 50 trouble codes (AC,Airbags, lost communication woth other ECUs,etc)
• Car Always Throw This Code When I Start The Engine For The Second Time In The Same Day. It rarely happens when the car is moving. Usually when idle or just after starting.
• When i run the car over 5k RPM all the dashboard lights come on for a sec and then disapears without any codes.
• When the MIL light comes on, car lose its acceleration as if the gas pedal is limited, ABS and cruise control.
• If i drove the car for a while the speedometer starts acting crazy... As Seen In Video
• When i reset the codes..everything comes back to normal..for days..maybe weeks Without Any Observations On The Car. And without any introductions oneday it throw the code again at any random period..random situation

Exclusions:
checked the following and excluded it from my list:
Water intrusion
Transmission or engine faults
Over heating
Fuses
Battery
Ground

[Yehia23]

Trouble codes scanned are attached below

[humfrz]

HELLO, Yehia23 ....and WELCOME to our forum ........

I'm afraid your car just doesn't like that music and is telling you so .....

Seriously, what power mods do you have, if any (including any tunes) ... ??

What is the last thing you did under the hood ... ??

We got some pretty smart folks that will come along soon and try to help you out. The rest of us would just be guessing. My guess it that the ECU has water in it.

If it were my car, and I hadn't modded it, I would take it into the dealer and ask them to fix it. At least in your case, when it's acting up ...... they can't say it's "normal".

Gad, I hope you get it sorted out.


humfrz

[cjd]

Anything plugged into the OBD port?

[Yehia23]

Thanks so much humfrz, no mods the car is stock.
I'm living in Dubai and believe me there is no water there ...only much of sun burns.
I wanted to have some info before i take it to the dealer.

Thnks CJD ..i usually remove the OBD after using it. It still throw the fault code when the obd is removed

[cjd]

Next guess is a short in the wiring harness, but the second start / idle only leaves me doubting. It may also be a bad ecu, but at this point I'm guessing wildly. Check the battery, make sure it's in excellent health and the connections are clean.

I've dealt with all three, and they all caused of erratic behavior. The failed computer sometimes decided it needed to honk (assuming the alarm module was being tripped). That brings to mind the cause of the failed computer though, a battery that shorted a cell out internally. The dealer insisted on jumping the car, and it ran but all the gauges were flashing and idle was horrible. And it toasted the body computer.

If the car has warranty, use it. Hope you get it sorted.

C

[steve99]

All those codes relate to communications between the various computer/modules in the car ie the ECU dash cluster traction stability system.


Be very unusual for all those modules to fail


However they all talk to each other on the CAN buss (controller area network) its a pair of wires connecting all the modules and the obd port.


It possible for a device plugged into the obd port to interfere with the can buss communication. It also possible for any one of the modules on that can buss to put rubbish data onto the buss and cause issues like your having.


It likely going to be a difficult fault to find.


Unfortunately a series of those modules ecu,dash cluster,imobiliser form a security set and if you isolate any of them car wont start.


if you have ant aftermarket bits plugged into obd port remove them. Some reverse cameras or entertainment systems plug into can buss to detect reverse




see here https://www.linkedin.com/pulse/autom...kiril-mucevski

[Yehia23]

Thanks steve and CJD, so the guesses are all about CAN bus or ECU.
I purposly drove the car wildly..took harsh corners and humps and it doesnt seem to me like a loose connection or shorted wire that comes and goes with the movement...its a permenant thing.
The issue disapeared for a week and only yesterday when i changed the oil the error came back.
well since its not a common fault i believe i have to go through trial and error.

[humfrz]

Originally Posted by Yehia23

Thanks steve and CJD, so the guesses are all about CAN bus or ECU.
I purposly drove the car wildly..took harsh corners and humps and it doesnt seem to me like a loose connection or shorted wire that comes and goes with the movement...its a permenant thing.
The issue disapeared for a week and only yesterday when i changed the oil the error came back.
well since its not a common fault i believe i have to go through trial and error.

Now, that could be expensive and time consuming.

I suggest you just quit being stubborn and take your car to a dealer or a tuner for a diagnosis and repair.......


humfrz

[Yehia23]

Finally I took it for Dealer after 1 week of testing they came back and told me it's the (Brake actuator assembly) and it will cost me 5000$!!!!!!!!!!!

I took my car back and i asked for diagnosis report, they refused to give me the report by i found my ways

Diagnosis:

1- Check Resistance between DLC and Vbus main line (CAN H - CAN L)
Normal condition: 57-63 Ohm
Actual:130.3 OHM!
(IF exceeds the limit go to point 2)

2- Resistance between terminal (DLC 3 branch line) (Main bus)
Normal : 114-126 Ohms
Actual: 130.3 Ohms
(If actual exceeds 126 Ohms go to point 3)

3- Check for open in Can Bus line (ECM)
Normal : 114-126 Ohms
Actual: 163.8 Ohms
(If actual exceeds 126 Ohms go to point 4. If value is within the limits replace the ECU)

4- Check Can bus line (SCM)
Normal : 114-126 Ohms
Actual : 119.0 Ohm

If Value is OK replace Skid control ECU

I asked them is it the ECU or Actuator they told it's coming in one package!!!

Probably they couldn't tell so they are going to replace everything within 5K$. I told them it's better to ask me for 20K$ and replace the car

Hope someone can tell if it's the actuator or Controller as i'd better jump with the car over a bridge than to give these bastards 5K!

PS. It's out of warranty