Unhappy 612 - Suspension control system failure and engine control failure

Hi can you give a description on how to access the frayed wires? And why they were frayed? I’d like to inspect mine that they aren’t in danger as well
Thanks
Mike

 

Thank you so much Diny for posting it. My car now doesn't start, says can bus error and transmission error. Had issues with the wiring under the passenger seat before, and when used the car last time, some things rolled under the seat. Will look for the solution there.

 

I know this is an old thread but the answer is interesting and maybe related to an issue I need to sort. Thanks for bumping this.

 

Hi,

I lifted the car searching for sign of an animal eating the cables, couldn't find any.
Issues are:
-Steering wheel not lowering when ignition turned on,
-not cranking,
-after a minute, transmission error beeping,
-trunk doesn't open from button,
-fuel cap cover doesn't open on button,
-central lock buttons not working.

If someone has a wiring diagram, or an idea of where to look, much appreciated.

 

Make sure your battery is good, real good. Also, sometimes the failure of buttons not working can be remedied by locking and unlocking the car 3 times.

 

Thanks Nospinzone, just bought a new battery, everything works except cart wont start and transmission failure coming up. I also dont hear the f1 pump priming. My obd reader which has a function of clutch relearning and f1 bleeding, doesnt show any fault codes.

 

Just ordered a new relay for the f1 pump. Most likely the issue is with it as it's not priming.

 

Some updates:
Changed the 50A F1 pump relay but did nothing.
After 20 minutes of reading fault codes i heard that maybe the f1 pump primed once. Then it let to engage 4th gear and back neutral, but no other gears.
Obd reader says either no can message, can line error, or permanent power supply absent error. When the dashboard is beeping for transmission error, or i try to engage a gear through obd reader, i hear a clicking noise from a relay in the trunk. I now try to fully charge the brand new battery i bought, and cleaned the connections on it.

 

battery update:
charged the battery to 12.9 volts.
Installed to the car, dropped to 12.7 volts.
Turned ignition on, dropped to 12.5 volts.
Is this normal? A relay is ticking in the boot every 20 sec.

 

Updates:
disconnected all relays, and found that 50A F1 pump relay makes the clicking noise.
After removal, the obd diagnostic tool couldn't communicate with none of the computers.
Reinstalled, and exported the results. What is interesting is that most of the computers show below 12V, although the battery is at 13V.
Also, there is two gearbox computer showing (Marelli CFC231 and CFC301), showing some identical and some different values. Hydraulic pressure circuit is -2Bar and 100Bar on the other.
The results:
Full diagnostic: https://reportview.thinkcar.com/report/think_car/?id=5b40da84ge3b54nR8cnR2YLrLr&type=diag&lan=en-us
Gearbox CFC231(issue: -2Bar, Voltage OK): https://reportview.thinkcar.com/report/think_car/?id=b693f883ge3b54nR8ctZoGLrlp&type=diag&lan=en-us
Gearbox CFC301(issue:100Bar, 43.6V): https://reportview.thinkcar.com/report/think_car/?id=1b2b8f10ge3b54nR8ctZ2YOMDh&type=diag&lan=en-us
Engine management left bank(issue 11.83V): https://reportview.thinkcar.com/report/think_car/?id=8ced41a6ge3b54nR8cOMKwDhtZ&type=diag&lan=en-us
Body system(issue 11.54V): https://reportview.thinkcar.com/report/think_car/?id=8ced41a6ge3b54nR8cOMKwDhtZ&type=diag&lan=en-us

Is it more likely a broken cable somewhere or i can go with replacing the f1 pump?
Thanks

 

Updates:
After being two weeks on vacation, when i returned home the car started and drove. Driven around 20 miles. After the last start, transmission error came on after five minutes in the traffic, and needed to trailer it back home.
Today i measured parasitic drainage in search for electrical issues, the result is 2.6A. After removing every fuse step by step, i found that removing ecu1 and ecu2 fuses caused parasitic drainage to go down to 50 mA.

 

Had the exact same problem

Power cut while driving and then suspension and check engine light came on

1. Tested wire continuity for MAF sensors to ECU

Turn out to be MAF sensor faulty, replaced and car runs fine now

2. Also did heat insulation wrap for wire harness around manifold area

 

Weird...

Suspension failure light came on followed by the check engine light

After checking wire connections and fuses and relays, all are intact.

All fault codes went away after replacing the MAF..

How is the MAF related to suspension failure?

 

I'm currently working on a 612 that has similar issues to the original poster. It has a MAF code (right side) and a suspension failure light on the dash. The f1 gearbox engages suddenly and chirps the tires. Scanning the car produces a host of CAN bus codes. After thoroughly checking the can bus and the wiring of the vehicle I found proper resistance everywhere I checked. The voltage on the canbus hi and canbus lo is also correct. I have a canbus sniffer and the bus shows no baud rate and no data flowing through the bus, confirming the bus is in an off state and not transmitting data even though it has power.

A CAN bus will typically only enter an off state if it has ~250 consecutive error frames of data being transmitted or its shorted. I have eliminated the possibility of short. The only thing that makes sense to me is the maf error is throwing off the data the right side ECM is trying to send over the CAN and the bus views the incorrect data as an error, then shuts down. I've ordered replacement MAFs for the car and I'll report back if that fixes it.

My life would be a lot easier if there were real wiring diagrams available for these cars.

 

Fix Update:

Replacing the right side MAF fixed the issue. It seems when the ECU's have a disagreement between the two MAF's the canbus for the rest of the car goes into an error state and shuts down.