Nissan Titan Forum banner

P2A03 cel code - help!

9K views 18 replies 4 participants last post by  Streamline 
#1 ·
Ok been going rounds with my truck. Have to get it thru emissions within the next few days and been chasing down this bug.

I have the p2a03 code for 02 sensor out of range. Bank 1 sensor 1..

Checked it on my scanner and that 02 is reading low and not cycling. It does respond to throttle posisition so it is getting a reading.

Readings I am getting -

.29v on bank 1
.45v on bank 2
Not cycling when warmed up

Replaced sensor same result
Flushed injectors thru rail cleaning no change

Fuel trim on bank 1 is running about -3% and bank 2 is running about +7% at idle. Seems to me the ecu is leaning out bank 1....

Maf reading is about where it should be.

Before I swap more parts need more suggestions...don't want to spend more good money after bad

Any help is appreciated
 
See less See more
#2 ·
You need to look for intake and exhaust leaks, as well as possibly a fuel pressure issue.
Your fuel trims do not look bad.
 
#3 ·
Checked for leaks first thing all manifolds are tight did the old intake mani carb cleaner test too nothing obvious. No audible leaks from exhaust got under the trucks wheel well with tire off to check.

Maf reading is about 7 grams per min at idle...

So the fuel trims being 5-7% different is ok?

Will check fuel pressure but I can't imagine one bank being lean and not the other if that's the case.

Also would point out it runs smooth....gas mileage is spot on.....
 
#9 ·
You can pretty much forget what's happening at idle. The ecu is seeing the a/f go out of range for a pre-determined length of time, probably as you drive. The voltage for this type of sensor can go well above one 1 volt, but somewhere around .5 is ideal.
My truck routinely runs about .45 for B1 and .80 for B2. The fuel trims also reflect that, but I have no code or leaks.

You did an ecu reset I assume?
 
#10 · (Edited)
Yep.

Did the maf reset then ecu reset per the manual...

At idle vs driving at 50mph there is not that much difference in the voltage readings per 0bd2

Where is the ECU getting its voltage reading for the scanner though? 4 signal wires all hanging out around 2-3 volts. Its NOT data, its voltage, but which wire? And how does that translate to .29v? The ECU must take the information from all 4, then make up its voltage we see on the obd2. if I knew the formula its using to calculate the A/F from this sensor then I can a least rule out the ECU being the problem.

I just want to see if what is seeing actually is accurate per the sensor.

Good ol 4 wire o2 sensors are easy, one signal wire.

Did do a reset last night, I must of did something out of sequence because it was misfiring afterwards on cyl 3...reset again and it cleared up.

still have 2 more tests to do...

fuel pressure and im going to rig up a pressure tester for the intake mani. After that im stumped.

I love the OBD1 on my 3000gt, I can turn off injectors individually, etc, makes troubleshooting a snap. Too damn many sensors and chicken dances on modern vehicles

At this point if it continues I may just have to get a waiver for emissions. Any repairs that are over $450 to get it to pass we get a 2 year waiver if we cant solve it.
 
#11 ·
How about freeze frame data.
U coukd use uprev to record fuel trims while driving to see if it jumps out of range. Ecu is unlikely. Have you reset kam .
 
#12 · (Edited)
Reset kam? Sorry enlighten me what that is abbreviated for

I realized after this post that the fronts are wideband sensors so voltage readings are pretty much useless at the sensor. However I could probably hook up my AUTOMETER wideband gauge to it from my car to it since it's the same sensor and see what the actual schitz ratio is.

Getting a p1148 code now after doing the maf reset and relearn last night. Closed loop malfunction
 
#14 ·
Kam = keep alive memory.
Basically it is a resetable memory that can be cleared after a repair is done.

You may be able to disconect battery. Touch both cables together for a minute. Sone cars kam must be cleared with a scanner. Im actually a ford master tech (or was a few years ago) nissans are not really my specialty. I will research this product and chime in .


Plus one to a bad electrical connection . Loose pin in a harness. Sonewhere?
 
#15 ·
Ya that was reset.

I'm pretty sure it's the maf...I had a shop check it out too and it seems to be getting leaned out regardless of what the sensor sees...and the maf was dirty prior to all of this. It's clean now but they noted that it's giving an airflow reading when it's off.

I didn't know it had multiple airflow sensors I'm used to dealing with single wire maf sensors......
 
#16 ·
There should be 1 maf and 1 air temp sensor, if I'm not mistaken.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top