# Darn Check Engine Light



## ABES (Jun 10, 2007)

So my check engine light is still coming on and its bugging me at first i thought the code was just system too lean bank 1. i was getting this code from a scan tool from checker. But when i had my truck in for the intake work they pulled 4 codes 

HO25 Heater Perf. Bank 2 Sensor 2,

P0171 Fuel Trim System Lean Bank 1

P0174 Fuel Trim Lean Bank 2

P1345 Crank Position - Cam Position Correlation

now my next plan of action is to replace all 4 o2 sensors and the fuel filter. anybody else have an idea of what all this could be. i thought at first all this was due to a leaking intake apparently not. 

The truck has a complete tune up new platnum acdelco plugs wires cap rotor new distributor intake gaskets


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## yard5864 (Nov 8, 2007)

ABES;534763 said:


> P1345 Crank Position - Cam Position Correlation


I had that same code a month or so ago in my car, i threw in a new camshaft position sensor, and problem solved. It was pretty cheap, installed myself.

Sorry, can't help on the other codes. O2 sensors sounds like the right path to follow though.


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## sechracer (Nov 4, 2007)

after the work was done, what are the current codes calling out?


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## B&B (Nov 4, 2006)

Are you sure they cleared the codes after they performed the intake work?

Your O2 sensor problems may be due to coolant contamination of the sensors from the leaking intake gaskets.. if the sensors are contaminated, it can cause your lean fuel trim codes as well due to them sending incorrect info back to the ECM.

The crank/cam correlation code is due to them either not clearing the code after they set the distributor position correctly after reassembling the truck, or the distributor is too far out of phase. Remember in a previous post when I mentioned about the cam phase needing to be + or - 2 deg with the crank position sensor? Thats what that code can be caused by.


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## ABES (Jun 10, 2007)

well it stayed off for 2 days after the work was done and i havent had a code reader on it yet but i bet if i go to checker there code reader wont show all or the right codes since its just a cheap generic parts store scanner. And the shop would probly charge me to have it checked again.


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## ABES (Jun 10, 2007)

B&B;534787 said:


> Are you sure they cleared the codes after they performed the intake work?
> 
> Your O2 sensor problems may be due to coolant contamination of the sensors from the leaking intake gaskets.. if the sensors are contaminated, it can cause your lean fuel trim codes as well due to them sending incorrect info back to the ECM.
> 
> The crank/cam correlation code is due to them either not clearing the code after they set the distributor position correctly after reassembling the truck, or the distributor is too far out of phase. Remember in a previous post when I mentioned about the cam phase needing to be + or - 2 deg with the crank position sensor? Thats what that code can be caused by.


It was pulling these codes before i told them to go ahead and do the intake i know they used a scan tool to reset the distributor after they put it back together but then i also noticed there are some marks they must have used as reference points when reassembling. This shop does a lot of engine work so hopefully they did it right.


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## B&B (Nov 4, 2006)

Gonna have to scan it to find out for sure. 

I'd have the place that did the actual work scan it, they should offer to do it at no charge if they're good business people.


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## ABES (Jun 10, 2007)

allright i will hopefully be able to make it there friday (its about 30 minutes away) and ya they are a really good shop nice guys to work with. Tommorow i will go to the local oreilly and use there scanner and see if anything pops up.


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## theplowmeister (Nov 14, 2006)

AutoZone will scan for free.


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## ABES (Jun 10, 2007)

theplowmeister;534839 said:


> AutoZone will scan for free.


Most parts stores around here scan for free im just not 100% sure that the scanner they use is as good at pulling codes that professional shops use.


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## B&B (Nov 4, 2006)

ABES;534844 said:


> im just not 100% sure that the scanner they use is as good at pulling codes that professional shops use.


Exactly ABES!

Wish more people understood that.


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## Spitz (Feb 28, 2008)

Well the o2 code is for the heater not for the sensor half of it.. Installing a new o2 in that specific location will cure that code.. The 02 sensor has a heater built into it to help it be more accurate quickly so the engine can run in closed loop and therefore lower emissions.. 


The lean codes are both set which probably means its something that will dilute the whole intake with unmetered air, such as a decent sized vacuum leak.. If it were only set for one bank or the other you'd be looking at something related to that one side of the engine or one or two cylinders.. Like i said if both codes are set for lean it'll be something related to the whole intake manifold, maybe a vacuum line off.. 

The crank/cam correlation is like bb said with the distributor being turned too far or the gear being off a tooth, anything over + or - 2 will set the code, it shouldnt be on..

Both the cam/crank correlation and the lean codes should be dealt with by a decent scanner.. You're going to need one that can get into the "factory" portion of the ecm to get any relevant data like the CMP ****** for the crank/cam corrleation and the lean codes you could get data with just a generic setup for looking at fuel trims to see if there actually is something going on.. Usually +/- 10% on fuel trims for Long term FT will set codes..

The 02 sensor just needs to be replaced is all.


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## Bowtytek (Oct 22, 2007)

i've seen a contaminated mass air flow sensor cause the p0171/p0174 causing the pcm to lean out the engine. try a new mass airflow sensor or a known good one from a buddies truck. may take a few days to see if it is fixed.


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## plowman4life (Jan 16, 2008)

idk what type of vehical you have but try screwing on the gas cap tighter. i know it sounds stupid. but it happens with a lot of trucks. if you dont screw it on real tight the sensor goes off and the check engine light goes on.


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## Spitz (Feb 28, 2008)

Ah bowtytek made a good point, something i overlooked.. Dirty maf can cause that issue as well.. Dirt coating the hotwire of a MAF sensor can make it inaccurate and read less air that what is actually being drawn into the engine.. Instead of replacement though, a simple spray of carb cleaner on the wire inside the sensor can cure it (if this is the issue).. This can be done just by looking into the sensor without any disassembly.


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## ABES (Jun 10, 2007)

i cleaned the mass air flow sensor several times with brake cleaner didnt change anything


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## Spitz (Feb 28, 2008)

You'd almost need to get a scan tool with some decent software then to go any further really.. There isnt a whole lot that can be done without looking at some information.. Any other way and you're just guessing.. No need to replace 250$ in 02 sensors though.. May as well put that into the diagnosis of your other issues.


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## ABES (Jun 10, 2007)

the 02 sensors are origional and the truck has 142K i was told they should be replaced at 100k


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## Spitz (Feb 28, 2008)

If you want go for it.. But if your on a budget then there is no reason to replace all 4 when the code only pertains to one.. The heaters do go out once in a while.. Chances are you'll end up replacing the other three in the next 10k mi anyway..


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## Charles (Dec 21, 1999)

plowman4life;534921 said:


> idk what type of vehical you have but try screwing on the gas cap tighter. i know it sounds stupid. but it happens with a lot of trucks. if you dont screw it on real tight the sensor goes off and the check engine light goes on.


I just leave the gas cap hanging off on my 2500 diesel. The suction effect was causing the engine light to come on and the engine to sputter and shut down. The air filter really needed changing but that didn't effect the suction effect. I was wrongly led to believe that it was the electrical controller that sits on top of the engine and that was a waste of $300.
You should also check your battery connections to see if they are not corroded. Check both batteries if you have two for charging


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## Spitz (Feb 28, 2008)

Ok guys, this has nothing to do with the codes hes having. The codes he'd have for the fuel tank issue as you describe would be evaporative emissions codes.. Diesels dont have evaporative emissions systems on them due to the fact diesel fuel doenst evaporate really.. If your fuel tank is being sucked into a vacuum charles you have a venting problem, either the gas cap itself or there is another vent on the tank somewhere.


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## ABES (Jun 10, 2007)

All right so i am going to order the new 02 sensors from summit today and when i did a search i got 2 options one is a 2 wire and one is a 3 wire so i am guessing that i need 2 3 wire ones (before the cats) and 2 2 wire ones (after the cats) is this correct thanks again guys!:waving:

http://store.summitracing.com/egnse...24667+4294908013+115+401120&Ntk=KeywordSearch

one other thing i dont understand is that they are both listed for "rear" location is that just a typo or what?


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## Spitz (Feb 28, 2008)

Why not just go to an auto parts store and get the correct OE fit ones.. Bosch is the manufacturer you want to get.


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## ABES (Jun 10, 2007)

The ones on Summit are the Bosch ones and its quite a bit cheaper than buying them from an auto parts store. Ive had excellent luck with buying from summit in the past they ship fast and have great customer service.


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## B&B (Nov 4, 2006)

ABES, your truck _*should*_ have 4 wire O2's all all four locations. But some of them had 4 wire pre cat O2's and 3 wire after cat O2's..

If your going to mail order them, roll under the truck and count the wires on them first to save yourself an exchange headache.


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## ABES (Jun 10, 2007)

Allright upon searching other sites it looks like i need 2 Bosch #13027 sensors for before the cat w/ 4L80E trans

and then i need 2 #13474 Bosch sensors for after the cat

I am not sure why the sensors depend on what type of trans the truck has?


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## B&B (Nov 4, 2006)

ABES;536029 said:


> I am not sure why the sensors depend on what type of trans the truck has?


Thats because of the cat/exhaust placement difference between the two transmissions. It changes the wire lead length on the sensors.


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## ABES (Jun 10, 2007)

Allright so i just crawled under the truck and its got 4 wires on every sensor in the exhaust. even though they all have 4 wires i still need 2 different types of sensors right??


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## Spitz (Feb 28, 2008)

The sensor are the same thing but the length of thier pigtails may be the difference in the part number.. To me buyign them from a local store saves a lot of headaches as far as warrenty and fit/form issues..


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## B&B (Nov 4, 2006)

ABES;536044 said:


> Allright so i just crawled under the truck and its got 4 wires on every sensor in the exhaust. even though they all have 4 wires i still need 2 different types of sensors right??


Yes, in most cases you will still need two different p/n's as the wire lead lengths will be different between the front and rear, and many times the connecting plugs are a little different.


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## ABES (Jun 10, 2007)

Allright sweet thanks B&B I will order up a set tommorow.


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## Green Grass (Dec 5, 2006)

i would replace the fuel filter that will give you the lean faults


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## ABES (Jun 10, 2007)

Ya i never got around to buying the sensors (it snowed so i was busy) i think now i am just going to try a new filter and see if that helps. i really dont want to be dumping money into this truck since i plan on trading it in this summer.


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