Topic: 02 Sensor Testing

[Deep-GXP]

First of all, I hope I am posting in the correct forum.
Second, I got a P2237 code yesterday.
Third, the following is information I recieved on test I should do on my car. Can someone help and specify exactly what I need to do and what I need in order to do it? Any info you can provide would be great cuz im really lost. Best I can understand is that either my ECM or O2 sensor needs to be replaced ??

Conditions for Running the DTC
P2237 • DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, P0338 are not set.
• The ignition voltage is between 10.7-18.1 volts.
• The engine is running.
• HO2S 1 voltage is between 1.48-1.52 volts.
• HO2S 1 heater is at operating temperature.
• HO2S 1 closed loop is active.
• The catalyst temperature is stable.
• DTC P2237 runs continuously when the above conditions are met for 2 seconds.


Conditions for Setting the DTC

P2237 • The ECM detects that the pumping current circuit is open.
• DTC P2237 sets within 4 seconds when the above condition is met continuously, or within 50 seconds when the above condition is met cumulatively.


Ignition OFF, disconnect the HO2S 1.


Ignition ON, test for 2.9 volts between the HO2S 1 High Signal circuit terminal 6 and ground.
If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.



Ignition ON, test for 2.5 volts between the HO2S 1 Low Signal circuit terminal and ground.
If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.



Ignition ON, test for 2.8 volts between the HO2S 1 Output Pump Current circuit terminal and ground.
If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.



Ignition ON, test for 2.8 volts between the HO2S 1 Input Pump Current circuit terminal and ground.
If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.



Ignition OFF, disconnect the ECM connector C1.
Ignition OFF, test for infinite ohms between each HO2S 1 circuit terminal and all other HO2S 1 circuit terminals.
If less than the specified value, repair as necessary.


If the ECM and all circuits test normal, replace the HO2S 1.

[DeepBlueGXP]

What exhaust/cat upgrades have you done?  If neither.  Pull your turbo heat sheet and see if there is any black soot on the inside of it and on the housing.  A leak would cause that code.

So would a bad CAT but that is a easy check.

If you have a Solo CAT upgrade, then you have to make sure the 02 sensor was moved and the bung extender was installed and in the new location 2 inches aft and about 2 o'clock on the exhaust from the existing 02 sensor location.

[Deep-GXP]

What exhaust/cat upgrades have you done?  If neither.  Pull your turbo heat sheet and see if there is any black soot on the inside of it and on the housing.  A leak would cause that code.

So would a bad CAT but that is a easy check.

If you have a Solo CAT upgrade, then you have to make sure the 02 sensor was moved and the bung extender was installed and in the new location 2 inches aft and about 2 o'clock on the exhaust from the existing 02 sensor location.

No exhaust or cat upgrades, all stock, although I will be getting a Solo Street Race exhaust soon.
I will pull off the heat shield and take pics to see what you guys think.
A leak??? umm, i will check the throttle body clamp.  On the stock rubber you have to chop some off if you're gonna switch to tbolt right?  I switched to t bolts but never shaved off that extra rubber, could this be causing the problem ?

[snaponbob]

No exhaust or cat upgrades, all stock, although I will be getting a Solo Street Race exhaust soon.
I will pull off the heat shield and take pics to see what you guys think.
A leak??? umm, i will check the throttle body clamp.  On the stock rubber you have to chop some off if you're gonna switch to tbolt right?  I switched to t bolts but never shaved off that extra rubber, could this be causing the problem ?

The problem is in the O2 sensor circuit. That means electrical, physical, or mechanical. A big enough air leak to cause code issues MIGHT be felt or heard. If your car has less than 36,000 mile it will be a warranty isse. In not, look at the wiring loom for both O2 sensors to see if they are damaged or melted. Since this is a heated wide band O2 sensor make SURE you get the proper one if you go that route. After you check the turbo/cat flange it will be interesting to know what you found.

[Deep-GXP]

I wiped some of that stuff off, you can tell in this next picture.

I wiped some of that stuff off, you can tell in this next picture.

O2 Sensor on TOP of cat

O2 Sensor wire continued.

O2 Sensor wire continued.

O2 Sensor wire continued.

O2 sensor on Exhaust in picture below, seems to be some damage to the wire

O2 sensor on Exhaust in picture below, seems to be some damage to the wire

Close up below of O2 sensor wire on exhaust

Close up below of O2 sensor wire on exhaust

[DeepBlueGXP]

Looks real clean, no problems there.  It has to be an 02 sensor.  Clear the code and see if it comes back (remove fuses 42/43 for a couple of minutes)  If it comes back then you need to trouble shoot...

[Deep-GXP]

Looks real clean, no problems there.  It has to be an 02 sensor.  Clear the code and see if it comes back (remove fuses 42/43 for a couple of minutes)  If it comes back then you need to trouble shoot...

I cleared DTC's with HP Tuners.  Do I still need to remove the fuses ?  If i do, do i need to unplug the battery?

[Deep-GXP]

Anyone know how i perform the test mentioned in the first post ??

[Deep-GXP]

No one ?

[snaponbob]

IF you have less than 36000 miles and IF your Pontiac dealership will ignore your mods (as a tune and high flow cat would not create this issue unless something odd has happened) then have them do the testing. Why? The answer to this will naswer your question a couple posts back. You will need a good hi impedance input volt-ohm meter (most all digital meteres are such), KNOW where the connectors are, and KNOW the pin locations on thos connectors. The interesting aspect of the test procedure you quoted at the beginning is that main tests call for a new ECM, but only the ECM being GOOD leads to an O2 sensor. Huh. If it were me, I think I would be throwing an O2 sensor at the problem, but then again I have idea how much they cost.   

[Critterman]

O2 sensors are part of the emission system and by law have to be warranted to 80k.  the high flow cat will definately cause you an issue at the dealer, they will see an easy way out of the warrantee work.

Not shure of the cost, put it has to be under 2 bills

[Deep-GXP]

I still have my stock tune on my stock ecm, I can put that back in.
I have my stock air box which can go in in 15 min.
Other than that I have only lowered the car and installed a dejon IC.
Oh, I also replaced all my clamps with t-bolt clamps.


Would I need put on my stock IC in order to take it in ??


So my understanding is that I probably recieved a faulty o2 sensor when I purchased the car, or my o2 sensor has gone bad for whatever reason and this should be covered by my warranty?

[snaponbob]

I still have my stock tune on my stock ecm, I can put that back in.
I have my stock air box which can go in in 15 min.
Other than that I have only lowered the car and installed a dejon IC.
Oh, I also replaced all my clamps with t-bolt clamps.


Would I need put on my stock IC in order to take it in ??


So my understanding is that I probably recieved a faulty o2 sensor when I purchased the car, or my o2 sensor has gone bad for whatever reason and this should be covered by my warranty?

If you have the OEM cat, reflash the stock tune and take it to the dealership. "Hey, I have a check engine light. Can you tell me whjat is wrong and then fix it under warranty?" POOF. Done. They probably won't know about the I/C, and it doesn't matter anyway as it couldn't possibly cause the code.

[Deep-GXP]

Sounds good.  I'll put my stock ECM back in (i bought an extra ecm for westers tune).


Only one thing though....I cleared the DTC with Hp Tuners.  Should I wait and take it in next time i get the code ?

[Go-N Def]

You definitely need to wait till you have a code.  In the dealer's eye's, why else would you be there?  Not to mention the fact that they would be a little suspicious of you for clearing it.  Of course, if you re-flash your ECM or put your old one back in, you're gonna loose the code again....

[DeepBlueGXP]

I cleared DTC's with HP Tuners.  Do I still need to remove the fuses ?  If i do, do i need to unplug the battery?

No, that was for those who don't have a code reader/clearing tool. 

[DeepBlueGXP]

Sounds good.  I'll put my stock ECM back in (i bought an extra ecm for westers tune).


Only one thing though....I cleared the DTC with Hp Tuners.  Should I wait and take it in next time i get the code ?

FYI, re-flashing the ECM after you get a code, clears the code.  I had a strange code on the way back from Lexington KY and I thought I'd re-flash to stock and let the dealer look at the code.  I use HPTuners also.  I put the stock tune back on and the codes were gone. 

So... If you want to take it to the dealer, swapping the ECM and waiting for a code is the only way.  If you wait until you pop a code and swap ECMs, the code will be erased when you remove the ECM for the swap.

[snaponbob]

Before you bust you ass any more on this let me mention two things.

1) This is a bit of a wet blanket and a STRONG case for not using second ECMs if you can avoid it. The connectors are simply not engineered to be "used" a lot. If you have ever taken a close look at the physical characteristics of the metal pins and plugs as well as the plastic plugs, they are not made of real stout stuff. Motor vehicles are designed and engineered to be assembled on the production line quickly and thus cheaply. They are NOT designed to be serviced. If one just looks at the wiring looms they are very well secured to AVOID movement. Be damn careful. The female connectors are weak and really hard to find. The plug housings are NOT available for field repair so you'll need a harness ($$$$) or a junk yard.
2) If the code is not present, then I agree about NOT taking the car in as there is, at the moment, nothing to diagnose. Leave the "tuned" computer in the a car and see if the problem reoccurs. It could be a momentary problem. I just had an air intake code of some sort on my Outlook and after a few drive cycles it went out. "Stuff" happens. If the code surfaces again THEN switch computers. BETTER yet is reflash the tuned computer with the stock tune. When you flash or change computers the RAM will "dump" so the learn memory will be gone so each will have to "learn" the car no matter what. If you don't have the stock flash on you HPTuners laptop, just switch in the spare, copy and save the flash (takes 20 minutes), LEAVE the spare IN the car, and either leave it stock of flash the Westor's tune in it. With a spare, there is no need to swap.

Make sense? HTH.