Hi all,
my bravo t-jet 120 goe's crazy every few days.
while driving, suddenly those lights turn on: ESP, ASR, check engine.
and shows the messages "hill holder unavailable see handbook", "abs unavailable see handbook".
Additionally: the cruise control stop working and almost all the trip data shows "----".

at the moment it happened, the car turn into "safe mode".
if switch the engine off and on, the car isn't in "safe mode" anymore.
if starting the car after few hours, everything good except the check engine light that still on.
if starting the car after a lot of time (next day), all good.

i connected to ECU with multiecuscan. the results:
engine:
P0121- throttle potentiometer track 2
P0221- throttle potentiometer track 2

gearbox:
P2906 - engine torque (from CAN)
P0856 - VDC messages (from CAN)

all messages records shows very low voltage (9.5V - 12V)

i made a record of the voltage and the hydraulic pressure from the gearbox while driving. i found that everytime the pressure goes up, the voltage goes to much down. (less then 13V)
but this is the wierd thing: the minimum voltage while driving is HIGHER then the voltage on the error records.

do anyone knows this problem? any ideas how to find what is wrong?

check the charging system with some load.
to me it seems the voltage regulator isn't working as it should.

can the battery do 15-20 starts one after the other?

i forgot telling about my battery tests:
idle voltage about 14V
minimum voltage when starting the engine: 10.22V
i also switched to a new battery.

the multiecuscan show always a difference of 0.4V between the gearbox ECU and the engine ECU. (if gearbox read 13.5V, engine read 13.9V)

never had engine starting problems.

i thought about faulty voltage regulator, but there is no clear sign to that.
i don't think 20 engine starts will testify about faulty voltage regulator. it only can tell about the battery capacity right now.

matansab said:

i forgot telling about my battery tests:
idle voltage about 14VOK
minimum voltage when starting the engine: 10.22VOK-ish preferably should be more. but it's still over 9v


the multiecuscan show always a difference of 0.4V between the gearbox ECU and the engine ECU. (if gearbox read 13.5V, engine read 13.9V)
If the earth cable was bad you would have gotten a higher voltage (close to 13.9v) so this kind of rules that out
A voltage test between battery negative and gearbox would still be nice to have ( should be 0 Zero or really close to 0 maybe 0,15v.



i don't think 20 engine starts will testify about faulty voltage regulator. it only can tell about the battery capacity right now.
That is exactly why i mentioned it

You check the voltage regulator using a multimeter with different loads. As long as the load doesn't change the voltage should remain constant ( 0,1-0,2v is acceptable ). A recorded graph with MES should be ok as well, but this is dependent on having good earth and power between the ECU and the battery

Click to expand...

As i understand you have the "Automatic" gearbox (the mechanized one) selespeed.
A problem with the hydraulic pump motor could result in it sucking more current that optimal ... resulting in a lower voltage.
How old is the car, years, miles and has it done much of the miles in city traffic?
A possible fault with the pump could be the motor brushes that wear. The resulting carbon dust gets everywhere and in time can cause a short-like effect.

You could get a clamp-on amp-meter and see what the pump is sucking. then check the internet for specs.


An other possible fault could be that the hydraulic reservoir is loosing pressure. that would cause the pump to start more frequently in a short time leading to a discharged battery. Check for leaks. a very small leak would cause a lot of problems.

thanks,
i forgot to mention, my bravo drove 98,000 KM, year 2011, with the robotic/dualogic/selespeed gearbox.

i will check the voltage between the negative pole and the gearbox.
i have checked and tight all terminals to the body. all looks good. also checked and tight the alternator output.

i have a DC clamp meter. i will check how much current the gearbox takes. hope to find the spec.

i think the reservoir still good.
when the engine is off, i raised up the pressure using the multiecuscan. the reservoir hold the pressure well.

i found that all the foulty systems using the same earth connection.
it suppose to be on the dashboard, maybe someone knows were can i find C038 earth?
i searched under the dashboard and behind the gauges, but didn't found it.
tommorow i will check behind the radio.

please check the attached pictures

if i wasn't so lazy, i would search extra 5 minutes on the eLearn and find the exact location :bang:
i found it just now, after one hour of searching + writing a post about it

I have some good news!

few weeks ago i discovered the throttle make wierd noise when i floor the gas pedal (key on MAR position, engine is off)
i let the multi ecu scanner to draw a graph with the gas pedal position, throttle position, battery voltage and the signals from the gas pedal.

i press the gas pedal slowly and hold it to the floor for a few seconds, as you can see the signal from the pedal is stable and stay constant when the pedal 100% pressed.
but the throttle angle is going crazy, and the battery voltage also drop about 0.7V



I took the throttle out, cleaned it, opened it and moved the potentiometer contacts to a place didn't worn yet.

i let the multi ecu scanner to draw a new graph. as you can see, the throttle angle now stay constant and stable. also the battery voltage





i made a test drive with the multi ecu scan, now there is no voltage drop while shifting gears. it seems like the problem solved.


before cleaning



after cleaning




the contacts i moved about 1 mm left




this is bosch 0280750137 or fiat/alfa/lancia 77363462
by the way, the official price here in Israel is 10,000 NIS (about 2500 USD)

Out of curiosity i just checked a online parts store ( from here in Romania) and the bosch code part is about 100 -120 euro ...maybe.

From Fiat yah.. i have no doubt they would charge that much for the same part.

I think the same part is used in the Stilo 1.4 16v engine (..and maybe every 1.4 16v engine fiat made )


When i put the key to ON ( not cranking), without pressing the accelerator pedal , my throttle valve moves quite a bit ... i thought that was normal ( is it????).
Does yours o that now?

a lot of cars makers using throttle looks just the same, all made by bosch, but with different inlet diameter and maybe other input/output. but looks pretty much the same outside and inside.

this specific throttle used in turbo charged fiat/alfa/lancia.


when you put the key on MAR without starting the engine, the throttle should move a little. and when pressing the gas pedal, it should moving according to the pedal position.
so i think you'r Bravo is just fine