Technical Grande Punto 1.4 8v Dualogic Not Starting

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Technical Grande Punto 1.4 8v Dualogic Not Starting

SzymonP

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Hi All
I got myself 2007 Fiat Grande Punto 1.4 8V with Dualogic transmission recently. The car was driving fine for two weeks but after one morning I just wouldn't start. When you turn key to the first position everything is fine, all lights come on and off as it should but when you are trying to start nothing happens. Starter not turning at all, no noise, just one click at the back of the car (from fuel pump?) I try to get it going again with my friend but we are nearly out of ideas at the moment. Checked battery and engine ground as on manual found on the forum. After connecting starter directly to battery starter is turning. What else can I check before I spend a fortune on towing and mechanic bills? Can dialogic transmission block start the engine? I can see that Speedstep oil level goes down.
 
In order to run the starter, the ECU needs the dualogic controler to give its consent; either the selected gear should be none (neutral) or the brake pedal must be pressed, assuming the other parameters (e.g oil pressure) are ok …
There is also a relay and a fuse for the starter motor, located in the engine bay distribution box.

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
 

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... Checked battery and engine ground as on manual found on the forum. After connecting starter directly to battery starter is turning.

How did you check the power and ground?
Describe with all the details.
 
Thanks, Bernie I will check if there are any pressure issues in dialogic. Is there any way I can bypass dialogic checks to see if the gearbox is the reason car not starting?

Aurick86, the battery was fully charged overnight, we also try to start with other battery and starting with jump leads. I checked ground as described in a guide on this forum using jump leads. Also checked if multimeter show voltage between positive on battery and different parts of the engine.
 
This fault is not necessary coming from the dualogic system, that's only one possibility. I would investigate it in a logical way, starting from the end, which you've already done by activating the starter engine (A020) relay directly. From that connection follow the wire to the distribution box (B001) and check for any cut/disconnection. At the distribution box verify the fuse (F35) and the command realy (T18) which must "click" when you try to start the engine. Remove the relay from the DB and direct feed it from battery to verify it's working, also check with DVM that the contact is closed when powered. You can swap the relay with another similar (amps) if defective. If all is ok check the connection of T18's coil to the ECU (M010) and finally check the connection / verify voltage is present @ wire(s) between ignition key and the body computer (M001).
If you haven't found the fault yet, it possibly comes from the dualogic controler …

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
 

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Hi Bernie

I checked all the above and everything looks OK. So it looks that problem is with Dualogic gearbox. I topped up dialogic oil but I can see Dualogic tank is "wet" at the front side. I can hear the pump goes on for few seconds every time and open the door and again when I turn the key. So it looks that it tries to pressure the system. I also realised that it don't change gears anymore. Before even if the engine wasn't working I could change gears after turning the key. Now when I turn the key, press the brake pedal and try to put N or R or a gear nothing happens. Also, the dashboard shows that car is on N but physically there is gear on as I can't move the car. What is the procedure to diagnose Dualogic? How can I check if dualogic is the reason that my car doesn't start?

Szymon
 
Hi All
Todays update: I got Multiecuscan today, so I was able to check gearbox ECU for faults. Here is a list what was stored in ECU on errors1 photo. Then I cleared all errors and car started :slayer: So it was definitely an issue with dualogic.
After I drive around the house for few minutes gearbox itself was working fine. But after all there is new error from gearbox ECU see errors2 photo. There is also gearbox oil leak so I will check this next week. I suspect gear selector sensor could be the fault. So I want to change it and replace dualogic oil as the old one doesn't look good. Was are the steps and procedure to do both tasks? :confused:
 

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hi i have the same problem one thing i have noticed is that the brake pedal has gone quite hard is this part of the failure process?
 
the brake pedal has gone quite hard is this part of the failure process?

Hi trelly72
Brake pedal went hard as you pomped it without the engine running. It is normal in every car if you press brake pedal few times with engine off it will go hard until you start the engine again and it is not related to the problem.

If you have the same problem as me you need service software to read errors from gearbox ECU. Then you need to fix what is wrong and delete stored errors from ECU. In my case topping up Dualogic oil let me start the car again and I was driving it last two weeks without an issue. I still need to figure out why Selespeed oil level went low.
 
A bit of theory ?

Here we go: modern cars have what is called "servo assisted brakes". That means that a system eases the driver's task of applying the brakes shoes to stop the car, which normally require quite high pressure on the pedal. The assistance is done via a menbrane in a half sealed tank whose exposed to a vacuum when the driver brakes. The vacuum is either created by the engine succion on petrol cars or by a dedicated pump on a diesel engine. In either case if the motor is not running there is no vacuum and therefore no assistance so the pedal gets "hard" …


BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
 
well i have had a diagnostic done on the car and it said that it looks like its a gear selector sensor fault from the gearbox ecu is this an expensive fix?
thanks
trelly
:cry::cry::cry:
 
Hi Trelly,

what's the error code ? If P1741, P1742 or P1743 it is related to one of the 3 position sensors that are on the robot. Each is about 30€ only and they are relatively easy to replace. If you want to DIY, there are tons of them @ the scrappy: they are the same as throttle body position sensor, from Fiat, Alfa, Opel, even some Peugeot … Basically its just a carbon track potentiometer in a custolmized shell. Be carefull tho as there is a special procedure to re-install them properly !!

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)
 
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