Hello all. I just pulled my trouble codes from my 03 H2.

P0171 System to lean bank 1
P0174 System to lean bank 4

I will be doing more diagnostics today but is there a quick fix to these? A cronic problem others have had with these codes and first place to look?

Manual advises
the system will go lean if injector is not supplying enough fuel.
A lean condition could present during high fuel demand.


Any ideas? thanks in advance

 

Vacuum leaks or plugged injectors would be my guess.

 

I started up my rig this afternoon and the engine light came on? just my dam luck! truck is running fine...
i didnt resent my oil life since my last oil chnage... will that trigger a check engine light?

 

No the light will not come on if you dont reset the Oil Life Monitor. make sure your gas cap is on tight. That is about the #1 cause of the Check Engine light coming on.

 

Thanks for the replies folks. Ya I did more diagnostics with engine running according to my manual and scan tool. All other systems check ok. Says that the left bank and right bank (2 oxygen sensors) were out of parameters. Apparently should be fluctuating between about 200 millivolts and 800 millivolts. Top end was around 800 but bottom was hitting 70 regularly. I will put a few bottles of injector clean and change the filter. The latter first.

I cleared the codes with the scantool to get rid of the check engine light. Oh also checked the O2 connectors which were healthy. Dont think its the O2 sensors. Both reading low / failing at the same time? I doubt it but who knows. I always buy the cheaper parts first and work to the expensive parts. Couple bottles of injector cleaner and filter is much cheaper than injectors or 02 sensors. Hopefully I can get the right amount of fuel squirting and that light will stay off.

RE that check engine light that came on due to oil change. The Check engine light only comes on when a trouble code is stored. I bought my scanner at Autozone. Its the higher end one at 180 bucks but I believe the techs at autozone could pull your code for free. Thanks again.

 

If you have a po171 (bank 1) and a po174 (bank 2), no such thing as a bank 4, opposite sides ofthe motor most likely you have a intake gasket leaking which is very common on GM v8 motors. The fuel cap would either give a small or large evap leak code. Felpro has just come out with an updated intake gasket that is well worth it. I did my gasket about a month ago and wish I put the updated one on oh well I will do it next time the gasket leaks

 

You are correct. Meant bank 2. Seemed to cure after a gas filter change and couple bottles of injector cleaner. Although I havent checked the O2 readings yet. Will do that soon when time permits. Thanks for the replys.

 

Well the O2 codes are back. It did eleviate the lean burn for close to a year. I think its the injectors being plugged and not shooting enough gas. Anyone know any Great! injector cleaner to use. I used gummout FI cleaner. Ill probably try a different cleaner.

 

dude when the 02 sensors keep setting the engine light on they are bad and need replaced, im having the same problem. I wish there were never any 02 sensors invented, their useless like an apendix in ur body and only cause problems. But its nothing major when that happens, or really nothing at all bc a bad sensor really means nothing , at all except they want u to go spend 60 dollars a piece and buy new ones so they can just fail later on. Its stupid, all this emmisions crap. Ive had mine reset a few times and about 10 miles later they just set the light on again. replacing them is the only way

 

Just a belated update. It usually stumbledat startup and set the engine light off. Plugged injectors. 2 bottles of sea foam on a full tank and light went out on its own. Idles fine now at any temp.