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Warnings on MID; BCM problem?

Discussion in 'Technical' started by mahen.jnk, Oct 24, 2013.

  1. mahen.jnk

    mahen.jnk Novizio

    Messages:
    36
    Hyderabad
    My 2011 August bought Punto Emotion Pack has done 30,000 KM. After getting my car washed last week it started displaying "Check LHS turn light", "Check RHS turn light", "Check front side light", "Check rear side light" warnings on the MID after turning ON the ignition. However, all the lights are working fine but the turn indicators are flashing fast.

    Disconnecting battery -ve for 10 minutes and connecting again didn't solve the problem. Took the vehicle to the service station and after examining with the scanner the SA said that the BCM (Body Control Unit) has gone bad and need to be replaced. whopping 30K including labour if it cannot be replaced under extended warranty. With past experience with the so called authorized service centers (not necessarily Fiat) how do I conclude that the problem is really with BCM before replacing such expensive and complex part? It could also be some wiring problem, failed sensor or short circuit right?

    My battery reads 12,8V with engine off and goes down to 9.8V during cranking. Is this normal voltage range. Just trying to make sure weak battery is not causing this problem.

    -mj
  2. PatchyBoy

    PatchyBoy Esperto

    Messages:
    2,438
    Bangalore
    The battery voltages indicated are fine. The BCM is right behind the fuse box, under the steering wheel and washing the car cannot cause that to fail, unless you used a pressure washer to wash inside the car :D

    That said, it is quite possible that some electrical connections were shorted, resulting in the issue you are facing. Did you by any chance use a pressure washer in the engine bay? The BCM is a computer and it is binary, literally. It either works or it does not. Displaying the error messages you are seeing is one of the functions of the BCM. The very fact that you are seeing these messages indicate that the BCM is fine. Check for water / moisture inside the fuse box in the engine bay, especially around the relays.

    May sound crude, but my bet is the problem will go away, if you park the car in hot sun, with the bonnet open for a few hours. If that does not work, try changing the relay responsible for the turn indicators. I do not buy the "BCM has failed" diagnosis.

    Rajan
    Last edited: Oct 24, 2013
    2 people like this.
  3. DRIV3R

    DRIV3R Esperto

    How was the car washed? Professionally? Body? Under-Chassis? Should take care when giving modern cars for wash at Local garages.

    Once, just few moments of lapse from my side resulted in the wash guy spraying water all over the door pads, power window switches, speakers. I blasted him like anything and immediately got compressed air blown thoroughly, then went home and did a hair dryer session for my Punto.
  4. mahen.jnk

    mahen.jnk Novizio

    Messages:
    36
    Hyderabad
    Thanks guys. I really do not know how and where the car got washed. I was not in city and wifey sent it for washing with the driver. Looking at the wash quality it must have been from local garage. Now the driver is not with us to find out the details.

    After that wash I have done a long trip for over > 1K kms on a hot day. Do you still think I need to park it in sun with bonnet open?

    Relay problem?? The lights are actually working fine except for turn lights blinking fast. So it cannot be open circuit or short circuit of the wires going to these 4 lights for which warnings are coming. But I might be wrong.

    Occasionally odometer keeps flashing...not always. If I start the car 10 times it happens 2-3 times and stays flashing till I turn OFF ignition. The SA said that he resolved this issue with the scanner. Will have to keep an eye on it for next couple of days.

    Do we have any technical person contact at Fiat India who can guide the service center to correctly diagnose the problem? Sometimes it displays only turn light warnings and some times turn light plus front side and rear side light warnings.

    Except this there is no other malfunction in the car. In fact, during my last trip Hyd to Chennai I got an FE of 25.6 with AC on all the time.

    -mj
  5. mahen.jnk

    mahen.jnk Novizio

    Messages:
    36
    Hyderabad
    ....not sure whether it is related to the above problem...When the driver brought the car from washing we also noticed the remote key was dead and also one of the keys got permanently pressed and struck. It must have drained the remote battery also. The service center guys said that the remote key is beyond repair and need to order the new one. We noticed both the remote key damage and above warnings on MID started at the same tume. Any relation to these two problems?
    Last edited: Oct 24, 2013
  6. PatchyBoy

    PatchyBoy Esperto

    Messages:
    2,438
    Bangalore
    @mahen.jnk - The issue is actually very simple. The BCM gets messages over the CAN BUS and takes appropriate action. If any of the bulbs blow out, the BCM will get a open circuit message and flash a warning. In your case, it appears that the BCM is getting a false open circuit message. Logically, the culprit would be the sender and not the recipient (BCM) in this case. Since the BCM is able to receive, comprehend and take appropriate action, I believe that the BCM is not faulty.

    Rajan
    Last edited: Oct 25, 2013
    4 people like this.
  7. rajivc666

    rajivc666 Timido

    Messages:
    3
    Kochi
    Hi,
    Here is what multiecu scan has to say..

    "The PROXI Alignment procedure is used to configure the modules connected to the CAN network of the vehicle. A flashing odometer indicates the the PROXI is not aligned properly. If your odometer flashes or you have added/removed/replaced CAN modules from your vehicle then you need to execute this procedure. The most common cases when you need PROXI Alignment is after replacing your Instrument Cluster or after replacing/retrofitting a Connect Nav module."

    Cant say if there is a real problem with the BCM, but you can request the ASS to do a PROXI Alignment procedure before replacing anything.

    Rajiv
    Last edited: Oct 25, 2013
  8. mahen.jnk

    mahen.jnk Novizio

    Messages:
    36
    Hyderabad
    Just noticed another problem. Earlier when I turn off the ignition the doors used to unlock automatically. Now they get locked automatically after reaching 20kmph as usual but are not getting unlocked after I turn off the ignition.

    -mj
  9. vj_v1

    vj_v1 Superiore

    Messages:
    933
    Hyderabad
    Is that a problem? The doors never get unlocked automatically, The 2 step unlocking has to always be done manually when the car is running or is turned off.

    I think the only scenario in which the doors get unlocked automatically is when you meet with an accident and that is a advertised safety feature. I cannot elaborate this since i have never experienced it.
  10. mahen.jnk

    mahen.jnk Novizio

    Messages:
    36
    Hyderabad
    Not sure about other variants but my EP used to unlock after I stop the car and turn off the ignition or remove the key (don't remember correctly ). After that we still need to pull the lever to open the door.

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