Is it common for engine ECU to go bad 355

hi.

how common is it for the engine ECU to go bad/faulty on the 355

I'm referring more specific to 96+, 5.2 cars.

what are signs of a dying/faulty ECU?

what have others experienced with this?

is any 5.2 motronic ecu, compatible with any region ( us, can, euro) car ?

thanks.

 

Hi
Not common at all to go bad they are pretty robust

Nothing else fits

Signs of going bad are the diagnostics stop working (CEL) or they just wont run

Any issues you are chasing or just asking?

 

it has been brought to my attention that the engine ecu
on my 97 GTB euro spec is faulty.

and it is plausible that the unit in my car now is not the original one
as it is labelled with yellow marker.

1. it is stuck with a reading of 1,100 degrees on right cat, bone cold, with constant flashing sdl. swaped in brand new cat ecu's same result no change, TC are believed to be functional.

btw: euro spec 355 has only two TC and two cat ecu's. does not have 3rd up top at valve.

2. car is running a little lean/rough.

3. ecu is not sending signal to valve to open at higher rpms.
valve has been tested manually and opens with vacuum. so it is functional

car is drivable, it does not go into limp mode, but overall there is a parasitic affect bogging down the car.

and I've been advised the most likely suspect is a bad engine ecu.

 

I could make a point for bad connections but the 1100 degree thing on the right cat tends to lead to a bad ecu

I would check connections to be 100% sure, remove and clean the ECU and look for pushed in connectors.
Check for correct signal inputs at the plug

One issue that happens is when the engine is taken out more often the connections get woofed up a bit by hanging or pulling on them



If you have access to another ecu try swapping it this will tell you right away.

BTW could you take a picture of the ECU for me and possibly any serial number on it? I have been messing with the 5.2 ecu's trying to map all the functions

Best of luck

 

I have located a used ecu from a US 1997 spider 6 speed.
so it's a 5.2 motronic.

but I am wondering if it will be compatible with euro car ??

 

Does the shop have an ECU from another car that you can throw on to test before buying another unit? Perhaps a friend with a 355?

Is it a big job or risky to take it out of 1 car and then put it right back when you're done?

I would let you have access to mine with pleasure but unfortunately it's a 95 motronic 2.7 US car.

 

I could not tell you for sure but my thoughts it would work, you maybe need to trick a sensor for the other TC.

Where are you located?

 

Why don't you have a look at the signals going into the ECU. There are 3 pins for those TCU signals, pins 14 and 15. 2.7V is about 1000 degrees F. See if the signal there corresponds to 1000 F.

 

Max'd out cat temp suggests an open circuit. Test for that.

Lots of reasons for a bypass valve to not work either and for that matter rough running.

The symptoms need to be diagnosed individually. In my experience the Motronic ECU is about the last component I ever suspect and to say it is rare is a gross understatement.

SoCal1 did kind of touch on it. The harness where it goes through the firewall is vey susceptible to damage. Bared or broken wires there are common. It was a dumb design.

 

Thermocouples are easy to test. As Brian suggested, check the wiring.

 

As far as swapping ECU's ?

It can't hurt to try but don't spend money on one yet.

 

thanks for the feedback.
I'm working with mechanic to figure this out.

would anyone be able to confirm which of the 10 ecu part #'s on table 7 on Ricambi website, applies to the euro 5.2 cars?

 

If you know your assembly number it is pretty clear.

 

yes.. I do know my assembly #..
ok I can see now, did not notice it before..

on the list of Table 7, it has descriptions (valid from Ass#) (Valid Till Ass#)..
its still not too clear..

but two part# fall into place for my ass#

PN 168600: CONTROL UNIT IGNITION -Valid till Ass. Nr. 26746 -Not for USA, CDN, AUS, SA and ZA -Valid for ABS

PN 172859: CONTROL UNIT IGNITION -Valid or USA My97 and CDN My97 -Valid from Ass. Nr. 23429 -Not for 355 F1.


neither of them say Euro, but I assume would be 168600, since it eliminates all other regions.

hopefully it doesnt come down to it, but if I do have to buy a new ecu, it would be used unit for sure.. its too bad cause ive found a used ecu PN 172859 above at a steal price. just have to figure out if its compatible with my car.

Eurospacers.com has a ton of used ECUs too.. but they are charging way too much for a used unit..

 

Finding the number of what you have is very very simple......you said your mechanic looked at yours and noted the yellow marker affixed.
That means he removed the cover which is behind the passenger seat....the Ignition Control Unit has decals from Bosch and Ferrari...the Ferrari Decal has the PN on it.
Visual verification of that PN is the only accurate way to determine what you actually have on the car.....you can do the VIN thingy and Chassis Build # from a parts book all day long, but you indicated that your mechanic believes the control unit has been replaced. If this is true then it is possible that the replacement unit used is not as per the parts manual.....I've seen a 355 from Dubai(UAE) that had a control unit that wasn't even listed in the parts manual..

I'll send pics to your email within the hour

 

correct, this is what I want to find out..

first I want to confirm which ECU pN, should be in a euro 5.2 6spd 355.
the Pn vary according to region/6spd/f1

from what I can see on Ricambi, the correct ECU pn for Euro 5.2 355 should= 168600
I will have to verify if my unit is this.

whether the unit in my car was replaced or not, if I can confirm its the Pn that it should be, then its a start.

if its not the Pn it should be for a euro 355, then i'll know for sure it was replaced..


then the next thing to determine, is if a USA/Can Ecu will function in a euro car..?
if the unit in my car, does not match to what it should be for a Euro, then that could be the answer, and is not compatible, causing the car to run rough, and/or looking for a 3rd TCU that is not there..causing the ECU to malfuntion, with irregular cat temp readings bone cold..

 

Don't assume anything...first thing is to use the VIN to find out exactly which market the factory built the car for.

http://www.ferrarichat.com/forum/140392375-post1.html

 

great tool.. !

confirmed. Digit 8 = B ( Left hand drive,Europe)

but I knew 100% it was Euro.. it was sold new in Germany.

 

Bruce, thanks for reposting that information.

 

hi.. just to update for people who may research this in future.. as threads often die off with no conclusion..

my SDL system is 100% corrected now..!

as described in previous posts, my mechanic was going nuts trying to figure out why the SDL was still flashing, even with new Cat ecus in..

as Rifledriver suggested above, it was an open circuit.. one of the wires was exposed..
fixed the wire and its 100% now.. but I did need two new cat ecus, the old ones were tested once the bad wire was fixed.. and they were still dead.

however it has been confirmed, that the ecu in my car is not the original for my assembly#.

for my Ass# the ECU should be PN 168600
but ECU PN 176224 is in my car..

its still for the Euro region at least.. so I dont see thats its a problem..

as for my BPV, it opens under permanent Vacuum.. my mechanic attached a vacuum hose directly, so that its under permanent vacuum and open all the time.

but without it, the BPV does not seem to be getting the signal to open at appropriate rpms..

as it is now is fine, so will just leave it for now.. my euro car does not have the 3rd TC probe at the top.. so im not getting any codes with the valve open..

 

Other problems can happen with a fully opened bypass - don't do it.

 

yes ive read it can have other affects..

its just temporary for now, since ill be storing the car soon..but for the few drives I have left, id rather have it open, instead of always closed for now..

other then codes, do you know of the affects of a permanently open valve..?
if I recall correctly, i read something about exhaust gases being recirculated back up into the headers..? and that you can take a piece of paper to the tail pipes to see if it sucks on the paper..