Technical Engine Light On - P1691 Code (Seeking opinions & experience)

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Technical Engine Light On - P1691 Code (Seeking opinions & experience)

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Aug 31, 2013
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About a week ago I drove 60ish miles and no problem. Car has been sat on the drive for about a week and now has the engine light on. It is rather hard to get started (you hear it try 2/3 times before finally firing up). Took it out for a drive around the block, but couldn't feel/hear/see anything out of the ordinary (other than the engine light).

My OBD reader has detected P1691 which, from reading other threads and Google, could be any of the following:

  1. Safety cut-off from controller
  2. Safety Cut off - Secure shutdown
  3. Secure Breakdown
Unfortunately these threads don't conclude in any obvious solution - hopefully this one can :).


It's been suggested it may be the MAP sensor or throttle control. What can you suggest?
 
Hi and WELCOME TO THE FORUM! :wave:

Does your obd reader have live data so that you can look at the MAP sensor readings and the TPS readings?

P1691 is one of those codes that has various different causes rather than pinpointing one, however the majority are linked to the throttle body.

You could also try a throttle body clean and re-learn procedure, as it will cost you nothing.

Have a look at these threads for more info.

Link
Link

Alan
 
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P1xxx codes are manufacturer specific so you will need to find out from a Fiat dealership what the code is or have access to these manufacturers (Fiats) codes or use Fiat diagnostic equipment.
 
Thanks for the welcome! :)

Sadly this problem has developed into something far more serious. I have now got the code P0115 - Engine Coolant Temperature Circuit Malfunction and the car will not start - just tries to turn over but never gets there.

I am currently suspecting the head gasket has gone because the engine coolant visibly rises each time the engine tries to turn over. I'm going to do a compression test tomorrow to try and confirm. Has anyone had any experience with this?
 
Really, compression testing is easy. Just -- charge the battery the night before -- remove all the plugs, unplug the TDC sensor (on Mk2s it's usually on a plate by cam cover), screw in the comp tester to plug nearest the timing side (#1 cylinder), get your assistant to hold the throttle wide open and crank the engine (about 5 revolutions of the motor). Write down the reading, continue, post results.
 
Autodata lists
P1691 Fiat specific
Fuel shut-off control - malfunction
Wiring, poor connection, fuel pump (FP) relay, throttle control unit, ECM

in basic terms
Check plugs for fuel cut off - fuel pump - the connections to the throttle body and the earthing strap on that

Check the relay for the fuel pump (energise low current side) and then check resistance across High current

The throttle control unit is the throttle body

---

p0115
is yes looking at the CTS
To test it
When coolant is 10C the resistance across the 2 pins should be around 3800ohms resistance
When its hot at 90c it should be low around 230ohms

Sensor sometimes fail, but not often, its also worthwhile checking the wiring

A daft thought, but have you tried removed the ECU connections - giving them some contact cleaner and refitting

it could be easily a simple wiring fault here

Ziggy
 
grapeman can you tell me the exact model you have including engine size and whether its man or automatic and year i have been doing some digging for you and need a bit more info to finally give you answers as i personally do not think your head gasket has gone.
 
grapeman i have done some extensive reading of approx 3200 pages of fiat (special docs)
lets just say for now fiat dont like the public having them, however after routing through i need to know the following before i can give you the answer/diagnosis that you need.

things i need to know is: when you just turn on the ignition does the fuel pump prime for about 2 to 4 secs then go off?

if the pump does, then does your engine fire periodically when trying to start?

if it does fire then is like a promising fire where it almost seems like it will run or is it a very feeble or slight engine fire?

in advance of you giving me these answers above i also need you to leave the spark plugs in but disconnect the plug leads (all of them but label them before you do so you know which lead belongs to which plug) then i need you to insert a plug into every lead and let me know if they all fire as they should when turning it over.

once i have all this info i should have your answer.
 
3200 pages.....looking forward to the answer.


Me too!

Ive only come across it a handfull of times and it will be fun to successfully diagnose without Examiner!

I think the problem may lay elsewhere but ill hold on that for now as bigbrava sounds like he's on to something.

Goodluck!

popcorn.gif


Alan
 
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Hi guys,

First off, apologies for the delay in getting back - it's been a rather hectic few days.

I was recommended by a friend, who's a bit of a petrol head :), to have it looked and quoted by a local garage as he too thought it was the head gasket. So I booked it into a garage and they confirmed the head had indeed gone. They replaced and skimmed the head, replaced a leaking water pump and all the sparks as they had become brittle from the excess heat.

So all in all theses were the issues:

  1. Head gasket blown
  2. Water pump leaking
  3. Heat damage to plugs and plug leads
Got to car back today and all is running smoothly. Little disappointed with the ODB reader giving P1691 however P0115 was a good indication towards the problems.


Thank you all for your help (in particular bigbrava)! You have been very welcoming and hope to stick around :)
 
glad its sorted my findings was poor compression on number No 4 cyclinder and too anyone who thinks i dont know what i am talking about kindly refrain from taking the ****.

one day it could be you who needs the help :)
 
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