Fuel Trim Too Lean P0171, Fixed Vauxhall Insignia 1 8

the code p0171 fuel trim too lean relates to the engine ecu detecting too much air being burnt in the engine cylinders thus compensating by increasing the fuel injected into the cylinders to give a richer mixture which throws up the trouble code.
A difficult problem to solve if your engine has no running symptoms as many things could cause this code such as air leaks on manifold and rocker cover, faulty injectors, fuel pressure regulator or pump, air flow meter, lambda sensors and engine ecu to name a few.
in my case here the fault was rectified by replacing a faulty charcoal canister purge (evaporative) solenoid.

[@richardjones3112]

Great video,this code is a nightmare to pin down-leaking brake booster is common for this.

[@colinbrown3364]

Common on the 1.8 the EVAP valve. If you can blow through valve it's knackered.

[@bazasulli4975]

8/10 times. Fuel trim to lean codes on Opel/Vauxhall/GM 4 cylinder petrol engies will be the evap purge valve. They are easy to get at. As many people say, blow through them and if air comes right through replace them. As Alan said you could do a fair bit of mileage before the ECM becomes displeased. They will usually present a fault on a cold start up (in my experience).

[@paulfianatravels]

Well done Alan finding that problem

[@patkelly7999]

Great job Alan, Thank You👌👍🙂

[@priteshchampaneri5101]

I always sensors with genuine parts, least you know they work right! Might be slightly more in price but worth it!

[@Codebreaker4981]

That's one to check in the future!😉 Brilliant work and video Alan 👍👍

[@jgrant2350]

This is exactly the problem with my vauxhall thank you I will change my purge valve

[@alan4x]

good luck

[@owss001]

Great job Alan, Thank You

[@alan4x]

Very welcome

[@paulfeatherstone7095]

Hello nice one Alan 👍

[@Diogo_A]

Top man thanks for the videos.

[@alan4x]

cheers Diogo

[@buur8178]

Damn, I changed my MAP, MAF sensors (10 years old though) and I closed the 90 degree angle hose on the EVAP. Funny though, my first part I wanted to change was the EVAP valve. However, I closed the leak on this angled piece and I got more power, but still I had the problem, so I thought the EVAP valve wasn't the problem.. and now seeing your video, I immediately ordered the valve and I will get it next week and I hope for the best. I hope it's not the intake manifold. That will be very expensive.. Fingers crossed! P.S. the net needs more video's like this!

[@ME-hw8ef]

Any update bud? 😂

[@buur8178]

@@ME-hw8ef it was literally the EVAP Valve.. So I could have saved myself a couple of 100 Euros. However, that the sensors I changed as well were more then 10 years old. It was also good that I changed them. Now my engine is running good again and the values in my OBD scanner are correct again and my car got through official inspection

[@ianwheat1577]

Good bit of info 👍

[@alan4x]

Thanks 👍

[@powerpower1797]

Good video.

[@ianwilkinson5549]

Cheers mate.

[@eddiejones.redvees]

My now x vw polo 1.4 tdi had i similar problem only on tick over the engine management light cam on Permanently one day I plugged a cheep scanner in the code Indicated that the valve for the slow running side of the engine was faulty I was going on holiday and the car was running ok under wise when a few days into the break I decided to take a look when I pulled the engine cover off I could see the problem right away the cover was rubbing one of the rubber pipes I did a temporary fix and put some Insulating tape around it the car came back to life I was always told by my uncle who was Head mechanic at the bus garage look for the simple things before you take the engine apart

[@pankajmakwana2300]

Using 5senses usually sorts out basic problems: see, hear, touch, feel, smell and breathe out through component. It works with more than cars.

[@dariuszkaps1444]

another mystery solved 👍

[@jamiewhittaker7399]

Hi ,I had same problem with my insignia,on/off eml light on.car had no issues like limp.mode or loss of power , I sprayed mass air flow sensor with electrical spray and eml light went out, Lucky it was simply and your video helped me so thankyou.......update.....light came back on after an hours driving so took evac valve off and blew through it,was very little air coming through but ordered new one and blew through that one and it was air tight,replaced with new one and light went out straight away and has been good for over 300 miles now ,I should of done straight away😂.thanks again

[@alan4x]

yes that electrical cleaner works well and maf do get dirty

[@davyarthurs]

If you have a vacuum leak, the fuel trims would be bad (showing positive numbers) at idle, but improve under load. Best graphing the fuel trims as easier to monitor changes. Negative fuel trims, shows the computer is taking fuel away. You don’t want to see anymore than plus or minus 10 (short and long term combined).

[@aaronditchfield781]

Ive got the ecn 17010 atm on pedal test my fuel consumption went from 29mpg to 15mpg. Maf or o2 sensor. Day after i got a 161450 and 161600 CIM fault i pressed the beake hard and heard a slush from water ingress. My guess is the loom inside has water ingress though not sure

[@pankajmakwana2300]

Evap valves are common problem with Vauxhall and P0171. Blow for test and replace if letting by.

[@ogukarakus]

Aftermarket or oem?

[@mosiahpeniston6429]

deleted the code (check engine light code ).But me being curious decided to checked my evap(took it off and blew in it no air on the other side )and check my mass air filter and cleaned it with a bit of brake cleaner,but my long term fuel trim is still sitting high and the short term is sitting at 13.. should i get them reset and see if they continue to rise again? or should once the problem is fixed they should go back to normal? the code hasn't come back but i am still wondering what was the problem

[@Chris-jy3dm]

Hi good info but does diesel have 0zero fuel trims the same I’ve had same code

[@neildean7515]

Great video, thanks. What model is the snap on tool you are using? My Launch 129 will not show fuel trims?

[@alan4x]

hi, that is a snap on solus ultra

[@bartoszk4812]

Haha, just today I watched the other car you tuber saying that those lean fuel trims can be a real bitch to pinpoint 🤣 he was actually showing smoke machines to detect leaks.. Frankly, after watching you for a few years now I'd say you fixing it had more to do with experience than luck 😉

[@yazan8841]

I need help please I’ve a noise in the engine and the car running perfectly only when I park I hear some noise , what do you think I’ll should check

[@andygill1977]

I'm having the same problem changed coil pack spark plugs and injectors also oil breather pipe since it broke when removing just so brittle and it still runs like a tractor I waiting on the purge valve to replace hopefully it's this lol. When do you give in thanks for the share

[@falcon7897]

I have the same code error P0171 in my Opel Astra J (P10) 1.4 Turbo + LPG. But this error appears only when I use LPG and not when I use Gasoline. Any ideas for what causes this problem?

[@MattyEngland]

Lambdas and MAF, always go genuine Bosch.

[@theoldskoolboyzzzz6958]

I changed the evap on my 1.2. Still no joy it’s sitting at 32 long trim and 8 short trim any help my friend

[@jamesjohnston-conn4049]

We're is solenoid on corsa 1.2 d. Code P0011 keeps coming up.

[@MrGodsking]

alan where is the body socket on a Ford anglia 105e,

[@MattyEngland]

Next to the USB socket 😉

[@TheHousty123]

I have the same car and I have literally just fixed the evap valve

[@davidhalfacre7220]

Mine was throwing P0171 and was running rough. Removing the oil filler cap was impossible with the engine running and I could hear a hissing noise from the cover I replaced the rocker cover with a new one (this also replaces the cam cover breather). Fault code went away and engine was running fine again

[@StefanKrunic]

Why was it impossible to remove oil filler cap with engine running ? DId it pull that much vacuum ?

[@cyborgmatumula650]

Where is garage sir I think I got same problem my one is 2013 petrol 1.8

[@philiplythgoe7173]

l have the same problem, changed a few things, can't find a purge valve for my 1.8 insignia at europarts . What part did you ask them for ?

[@pankajmakwana2300]

Get it on internet.

[@philiplythgoe7173]

@@pankajmakwana2300 l know i can get a part off the internet (i want the right part). europart don't do one.

[@pankajmakwana2300]

Get it from eBay, don't go for very expensive ones, once the diaphragm tears it needs a new one. I have said blow through to test, order one look for similar on the engine behind the cover and you can't miss it. Replace reset em light and run it and you will be fine.

[@MartinJones-tl9kt]

Genuine Bosch on Ebay £15 !

[@youngnunu7651]

I have a 1.6 insignia and on ignition there is no fuel to the rail but I have powered the fuel pump manually and it’s pumping fuel. I’m confused because the fuel pump works fine operating it manually but once I try to stay it it’s struggling to start feels like fuel starvation can anyone help I have check med fuses and relays and they are fine please someone help me

[@pankajmakwana2300]

Injectors could be blocked. But first there is a valve on the rail. It should register about 60 psi on footpump. Try restarting to see pressure is around 60. If it is problem is not fuel pump but may be a faulty injector(s). Good luck.

[@philiplythgoe7173]

GSF don't do a purge valve for my insignia either...

[@avtarsinghhoonjan6660]

I had same fault code on my insignia same sensor was at fault.

[@clueless6559]

A decoke usually sorts this ,

[@simonparkinson1053]

Threw me the first time I had that. You'd think it would actually be running rich rather than lean - it might initially but then go lean once all the fuel vapours are purged and it's pulling mainly air through the tank vent

[@johnysmart8545]

you need op-com off e bay is a vauxhall diagnostics anything with a plug on or sensor attached to it the program picks up. ford do one too called f-super they are a must for any toolbox they even work on most older obd1 systems too

[@andyduplooy363]

PCv velve system

[@glitterpop9467]

Evap on a vx every time

[@saintnick7]

Purge valve...

[@simonsmith2802]

If manufacturers didn't put crap electronics in cars we wouldn't have this problem at all electronics doesn't need to be in cars cars used to run better on a distributor and points and carburettors it's just a pile of junk

[@foxy1960]

Absolutely 100% correct. Designed to fail for people to fire the parts cannon to make money for the motor industry

[@Sherlockshere]

Can you help I have a vw passat 2 litre tdi brm engine 170bhp and dpf,flashing coil light are on and when engine management light joins the party the fault code is turbocharger boost control position sensor circuit range/performance along with particulate filter restriction-soot accumulation bank one. Is the turbo fault code affecting the dpf and is it just a case of replacing the turbo actuator and doing a regen that would get it out of limp mode. Can do 80 downhill but only 25 up hill Cheers

[@keithavian8129]

Could be the egr cooler that's blocked, it's quite common on the vw2.0tdi engines, it's bolted to dpf