The Dreaded P0171

[Micholas]

So next on my list is to finally sort this out. 
About a year ago an EML came on, after a plug in it was ‘P0171 System Too Leak Bank 1’. Quite common and equally stubborn apparently. 

If I clear the fault I can literally go 2 months without it appearing.. but then it’ll come back, usually when I’m doing motorway miles. Looking at the DTC chart, the amount of parts that could impact this and should be replaced is absurd. Injectors, AFM, Coolant Temp Sensor, all 02 sensors and ECM. Even though you should replace one then check, then replace the next and check etc. knowing my luck it’ll be the last part that fixes it. Maybe I should start at the bottom 😉 

The airflow meter and temp sensor are cheap and easy enough, but the others will all end up costing me a fortune. I would just take it to the dealers to see if their software can pinpoint the exact cause, but they won’t do any engine diagnostics on my car because it’s got an LPG conversion! 
 

Anyone had any experience with this? Noticed any trends? Obvious fixes? 

 

 

[Malc]

9 minutes ago, Micholas said:

because it’s got an LPG conversion! 

might the people that did the LPG conversion be able to do some appropriate diagnostics for you ?

Malc

[Micholas]

2 minutes ago, Malc said:

might the people that did the LPG conversion be able to do some appropriate diagnostics for you ?

Malc

It was done by the previous owner. The place that I use to do the LPG servicing specialise in LPG systems, but don’t strike me as being wizz’s at technical V8 diagnosis. 

[cruisermark]

Have a read here - quite a lengthy and detailed post - hope you get it sorted:

FINALLY SOLVED! P0171 and P0174 Codes!!!! - ClubLexus - Lexus Forum Discussion

[runsgrateasanut]

This video has great reviews though not a Lexus it may be of help?  https://www.youtube.com/watch?v=SugtR4KMIDU

 

 

[Razor61]

15 hours ago, cruisermark said:

Have a read here - quite a lengthy and detailed post - hope you get it sorted:

FINALLY SOLVED! P0171 and P0174 Codes!!!! - ClubLexus - Lexus Forum Discussion

That's a cracking post, from reading the post the issue was on an RX I think but the details on what causes the error codes is very interesting and informative.

[Razor61]

The car has been converted to LPG so have a look at the YouTube video below and you could have the same issue.

https://youtu.be/NOesoTKyalc