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View Full Version : Any Fiat 500 Mechanics on the Board?



budzinsk
08-18-2013, 11:11 PM
Hi everyone. I am in the process of bringing a 2013 Pop back from being a flood car. I have some pretty detailed questions around how the BCM communicates with the ECU and determines when it will allow the car to start. I believe I need to have the BCM reprogrammed for the car, but before I take it to the dealer I want to make sure I covered all bases. Since a wiring diagram is not available I am limited to what I am able to troubleshoot. If there is someone who is is familiar with these components I would appreciate it if you could PM me and answer some questions.

Thanks so much!
Rob

otbiker
08-19-2013, 05:51 PM
I'm not a Fiat mechanic per se, but experienced in ECM / BCM. I understand you have a no crank situation. Are you using the old ECM / BCM? If new, you'll need base programming from Chrysler. Do you have any CANBUS errors or can you not get past the BCM?

budzinsk
08-19-2013, 08:13 PM
Thanks so much for the reply. Ok, I replaced the main wiring harness in the car along with the Key, ECU and BCM from a donor car. I specifically asked that the Key , BCM and ECU com from the same car so that I did not need to reprogram. I was told they did, but I am honestly not 100% sure. When turn the key, the dash lights all work, I am getting a transmission error - which is due to the trani position sensor, and I do not have the dash in yet so I am getting air bag errors. It is my understanding that none of these are a requirement for the car to start, but I am not 100% sure. When I turn the key, I hear a click in the front fuse box (relay), but the starter does not crank. Also, i pulled the starter relay, and the wire from the ignition switch to the relay has power when I turn the key to crank. There are 2 thin wires to the relay that I assume come from the ECU/BCM that tells the relay to engage and allow the starter to crank. My thought is the BCM or ECU is not allowing this to engage.

I did notice the Check Engine light is on in the dash before I try and start it, so I am thinking it may need to be reprogrammed but I am not sure. I have a ODBC II reader, and I did not get any code when I tried it earlier in the week. However, I was trying it before I had the key transponder antenna hooked up, so I may be getting an error code now - I will try later this evening. How can I tell if I have a CANBUS error?

Thanks!
Rob

budzinsk
08-19-2013, 08:21 PM
Ok, I just checked and the check engine light is no longer on. Also, I did a ODBII scan, and no codes showed up (8888)..

otbiker
08-20-2013, 07:46 AM
I think you need to resolve the transmission position sensor. This will definitely cause no crank. Speaking of that, the crank sensor also has to be good. Was the engine submerged? Debris at the crank sensor or cam sensor?

budzinsk
08-20-2013, 12:33 PM
Thanks. Yes, the engine had water up to the oil pan, but it also splashed around. No water made it into the internals of the engine - I have confirmed this. The transmission has water in it and I will replace within the week. This should fix the trani position sensor issue. As for the other sensors, they appear to be potted so water should not have affected them - but I will take a close look at the crank position sensor...