Technical Stilo Loose connection P1688

[Sparkster]

Hi all
My Stilo 1.4 occasionally gives a "Loose Connection" fault on trying to start. Turning the ignition off and on again usually (but not always!) overcomes the problem within a few attempts. I had it in with our local car repairs place (not a Fiat dealer) who diagnosed it as a P1688 code but since its intermittent wasn't able to get to the cause of the problem. Does anyone here know what the P1688 code relates to and where would be best to start looking for the "loose connection". Is the infamous D4 a good place to start?

Something else maybe worth mentioning here is that on the one occasion when I had to jump start the car the fault disappeared as soon as the other car's battery was connected. This, and the fact that its more troublesome when cold, would seem to indicate that the fault may be related to battery voltage? Also the problem has (so far!) only arisen on starting.

Thanks in advance for any help!

 

[bozzy]

Welcome to the forum. Hopefully a mod might put this in the Stilo tech section and I'm sure decks/rich/t14086 will be able to help.

 

[jug]

that code means fuel pump controller failure. it could be due to poor current supply from the battery, but it sounds like you have a poor connection. if the engine cranks at normal speed but it wont start then the battery is obviously fine and the reason it is not starting is the fuel pump. you could check the wiring connector on the fuel pump.

 

[T14086]

From memory (not to be relied on!) P1688 is common stilo error thrown up often due to voltage problem(s) & mostly ignored unless a fault is suspected in that system...like the common U1600 key error code etc

 

[Sparkster]

Many thanks for all the replies. Some useful pointers there, hopefully I can get to looking at it tomorrow. What puzzles me is why the problem only affects it starting rather than actual running.

 

[T14086]

You yourself mentioned voltage.It's the logical place to start - good battery? correct battery (correct rating & pref fiat battery) ? good earths? Have you a battery cover fitted etc. Got to start at the beginning

 

[Duncan C]

Hi
I have just had the joy of the above loose connection warning. Unfortunately the usual fiat fix of turn it off and have another go has failed to work.
The engine turns over as normal but it just won't catch. I guess this points to the fuel pump.
The question is before I start rolling around on the freezing cold ground, were is the fuel pump? Front, back? If someone could give me a clue I'd be grateful.
Also is it really going to be a loose connection or is the fuel pump most likely FUBAR'd?
Thanks in advance.

 

[Argonought]

I guess this points to the fuel pump.

Sounds like a stab in the dark to me

If it's not starting then wouldn't basic fault finding prove more useful :chin:

 

[Duncan C]

Argonaught
I was basing my assumption on the reply above that said that fault code was the fuel pump. That and the car behaving like a carburated car with no choke on a cold start meant I thought it could be a good place to start.
I have checked all the connectors I can get at in the engine bay. The fact the engine spins at a normal speed leads me to think that:
1 the battery is not flat
2 the battery connections are not loose
3 the starter connections are not loose
So rather than randomly proding connectors I thought I would go to a previously mentioned potential problem.
Were would you recommend I start?

 

[T14086]

Argonaught
I was basing my assumption on the reply above that said that fault code was the fuel pump. That and the car behaving like a carburated car with no choke on a cold start meant I thought it could be a good place to start.
I have checked all the connectors I can get at in the engine bay. The fact the engine spins at a normal speed leads me to think that:
1 the battery is not flat
2 the battery connections are not loose
3 the starter connections are not loose
So rather than randomly proding connectors I thought I would go to a previously mentioned potential problem.
Were would you recommend I start?

Helps if you tell us what engine you have (if petrol you should be able to hear pump prime)

 

[Deckchair5]

I have P1688 as "Metering Oil Pump Stepping Motor Circuit Malfunction" but that's really the throttle body (Plain english award I don't think. Isn't it fun?)


So that's where I'd go and check the connector there but remember "loose connection" is a bad translation of what it really means which is "lost connection" ie "Where's the bloody thing gone?" ie open circuit

 

[Duncan C]

Sorry forgot the engine it is a 1.2 16v from an 02 plate 5 door.
I've just popped out and checked and I can't hear the fuel pump priming.

 

[stilon]

I got the same problem and in my case the cause refers to serial communication malfunction by ignition. As soon as I press the ECU connectors by hand the communication is reestablished and the fuel pump start working and the engine may be started. In my oppinion the ECU pcb has somewhere a micro-crack determined by vibrations and material failure. Because an ECU replacement seems to be expensive I intend to examine the pcb first and resolder at least the connection pins. A schematic will help but I did not found it, maybe someone have it and post it. Come later with the results! Thanks a lot!

 

[stilon]

Indeed! My assumption was correct! I have opened the ECU box (the silicon seal is not a big problem..) and discovered a thin crack on PCB (!!!). Beside this, I have also resoldered the connector pin terminals from PCB, one by one (each, ca. 3-4 second by 300 C dgr. using a solder station). After reassembling I was able to start the motor again. Until now it works fine!

 

[stiloturkey]

Re: Stilo Loose connection alternatör fail

hı.I am among you participated in the new.my vehicle has the problem of loose connection.stop is on the move.I changed the battery new,After cleaning the throttle was,mechanics and service is what you can not find fault.We checked the battery cables,relays cleaned,check the crank sensor ethics,I changed the heat sensor,but I could not find the problem.Waiting for your help.
ı am stilo 2003 1.6 3d dynamic petrol and lpg.

 

[speedyjorge]

I have a Fiat stilo 1.6 16v 2002 and "HAD" that exact problem and i got it fixed myself.
ASR failure cable connection loose and engine would stop. Very frustating and dangerous.
After fitting a new "diesel" battery, checking the brake switch, checking the earths and the D4 connector, cleaned all the connections pin by pin,checked all wiring in the car and still ASR came up.
Until I finally found a stilo for parts and bought the throttle part the ECU and the fuse and relay box from the front and changed all the parts apart from the ECU that didn't work because of the key codes. So the problem was from the throttle part, the square part at the end of the wide air intake pipe were it connects to the engine. Since then i noticed that the idle speed is much better, before the part change the rpm used to move up and down but just slightly about 100 rpm. I dont think the fuse box from the engine was at fault because i checked all the fuses and connection from the old one and everything was perfect, but i choose to change it anyway. Engine is much more responsive smooth and fast and most importantly no more ASR FAILURE Thank GOD. Check your throttle with attention to se if the rpm move slightly if they do most likely cause is the throttle part. I hope this will help. Good luck.

 

[ramborobert]

There is a guide in the guides section on how to clean the throttle body and i doubt replacing it would have cured the loose connection problems. The loose connection problem must have been in the fuse box.

 

[RedRuby]

Last night I bought a Stilo 1.6V 2002, and in less than 24 hours, it has left me stranded.

Waited for the checking to finish, turned key ... nothing...
ASR warning, loose connection, lock sign came on, as well as a number of other warnings... just refused to turn on, click over and let me drive!

Do i need to return this car quickly, or has anyone who's had this problem actually cured it? and if they have... for how long?

Really peeved, as I bought this car as a winter car, so that I could put to bed my 94 GT celica..

My 17yr old lets me know it's ill by preforming badly and making the wrong noises ... these modern cars just flash text messages, scream warning lights at you and decides for them selves that they are in control, and will start if they want to start..

Urgent assistance needed as it is being towed tomorrow, and dont know whether to ask them to dump in back on the sellers drive

 

[speedyjorge]

I thought i had fixed the loose connection problem. But unfortunately NO this stupid car is making me loose all hope in ever fixing it. I'm running out of ideas and after spending so much money on it i didn't want to sell it, not to mention all the time i lost fixing it.With fiatecuscan i got loose connection with the laptop on and got errors U1600 and U1601. Can any one advise me because i'm at my last straw and if i cannot fix this i'm selling it and that's the end of it. Thanks.
Things done on the car: D4 cleaned, ECU connections cleaned, wiring checked nothing wrong, earths checked, new big battery, battery tested, key antena connections cleaned, new throttle body fitted, new fuse box engine side fitted, new air filter, new oil filter, full service done, new wheel bearings, new brake pads, new front bumper and spray, and new heavy duty drop links fitted. Not spending one more dime on it. Car runs like a dream except the stupid loose connection. Curse you on board computers.

 

[emzo]

U1600 - immo related
U1601 - CAN data bus