Troubleshooting Help! p0120 & p0121

[Lawngoose]

I have been throwing these 2 codes since I did my header install and EGR delete.

DTC Code : P0101
Description : Mass Air Flow (MAF) Sensor Performance

DTC Code : P0121
Description : TP Sensor Circuit Insufficient Activity

For the p0101, I am assuming to clean the maf, and reset and try again.

But I wanted to see if you guys have experienced these codes and have any tips and advice.

Thanks,
Matt

[Reptile]

Check wiring, mainly on your O2 sensor. The TPS, MAF, O2 share a common fuse because they all work together. If a wire is grounding out, it cold blow a fuse as well. Might check in the under hood fuse box I think it's engine cont 1 & 2, location 25-26 or something like that. If you have a Powertuner, you can check your MAF frequency, O2's etc to make sure they look like they're operating like they should. If something doesn't look right, you can start looking there.

[Lawngoose]

Thanks, I had some exhaust welding work done this morning at the Y for my pacesetters, but the o2 was out and I got these errors when my EGR was leaking.... I first saw these codes after I did my header install.

[Lawngoose]

Here is a nasty scan.

RACETRACK_10-21-2008_9_20_03_A from lawngoose -- Scan Depot dot net

[Lawngoose]

Checked fuses, all appear to be ok.

I think I am going to buy a new o2 sensor, since it was messed with when I installed the y pipe.

I also may pick up a TPS sensor... even though I doubt mine is bad... just for peace of mind.

[TDCRacing]

Yeah reset the codes. If not and you've cleaned you're MAF then it's more than likley bad.


I have an o2 sensor if you need one. I'd bet a thousand bucks that one of the wires for the extension harness has a bad connection.


It happend to me a bunch of times.

[TDCRacing]

If you have a Powertuner

Who has those anymore?

[TDCRacing]

Brian mentioned a o2 sensor but i didnt see where you mentioned one. Do you have a code for you're o2 sensor too?

[Lawngoose]

I have reset the codes numerous times, actually my car has shut off once or twice... like it would with the egr leak. But I have a aluminum plate on it that is copper RTV'd. I may remove that again and reseal.

Im not getting a code for my o2..just these

DTC Code : P0101
Description : Mass Air Flow (MAF) Sensor Performance

DTC Code : P0121
Description : TP Sensor Circuit Insufficient Activity

I just bought a new o2 sensor. And the extension harness was from zzp. I am going to check those wires when I get off work.

I also bought some electrical parts cleaner, but I have never used it before.

[Lawngoose]

Ok guys, I think I found the problem.

Got up under it, and the front o2 sensor is wedged inbetween the Y pipe and the under carriage. The wires are pinched bad.

Now I am assuming thats whats causing all these codes... but now the question is... how do I fix it?

The only thing I can think of is to have a muffler shop weld me another o2 bung in a better location.

Any ideas? I got to get my DD fixed soon.

[Reptile]

On pacesetters, the stock O2 sensor is too long and will rub on the body, obviously......A Denso will not because it has a shorter body. See about finding one.

[Lawngoose]

Thanks!! Where can I get a denso?

Also, I assume an OEM replacement w/plug?

[TDCRacing]

Auto Parts Fast at RockAuto


Look under your year and model and under oxygen sensor. It is in with all of the other o2's and yes It comes with a plug.Wich will need to be cut and extended with the same gauge wire.

[Reptile]

You can also get one through ZZPerformance.com

Theirs isn't universal, plug and play. Just be sure to get the racing one...just in case in the future you want to use leaded race fuel for whatever reason.

[Lawngoose]

Before I purchase one, I am going to see what another exhaust shop can do for me.

I went to one this morning to get the y-welded, but at this point, I dont care if they knock my floorboard in.... HA But I want to see if they can contribute, since if I have to order it... and still go to work.

I appreciate everything you guys have contributed... I am in the panic/breakdown/sell the gtp.

I will update this tomorrow with the results from the shop, im hoping the can knock the *&$@ out of what looks like the floor board pan to allow a stocker to fit for time being.

Crazy LTFT's and 16 mpg and misfires cant go on much longer. Me nor the car can take it... she ran so good before I got headers, maybe I can bring her back.

-Matt

[Lawngoose]

:::: Update ::::

Took it the shop, had them relocate the o2 bung and replace the sensor.

Now nothing is hitting or pinched.

However, even after that, im still throwing the same codes.... As TDCRacing mentioned earlier... I am thinking its the o2 extension harness.

The plan is to do a conductivity test on each pin on the harness to see what the results are. I am thinking this is the best way, but if you guys have a better idea, let me know.

If the harness pans out ... I dont know what to do... I have triple-checked all the wires of the MAF, TPS (even replaced it).... but have not checked the o2 harness yet.

[Lawngoose]

All wires were fine. All voltage's checked out.

However, when scanning... my MAP was 99 at idle.

Come to find out the vac line under the snout at the T connector was not fully in, causing a small vac leak.

PROBLEM RESOLVED!

Now its off to tuning my car to get my LTFT's back in shape.

Thanks for all the help and input guys

[Reptile]

Good deal!

[TDCRacing]

No problem. Glad you got everything worked out.