O2 sensor codes

[CobraKing]

@***** My truck's got about 200K km on it, so like yours there's a lot of idle time and resulting fuel pump run time. Looking around on some other forums it is highly possible that the sensors themselves have gone bad and having them replaced cleared out the issues for those people.

Are you noticing the truck running rough? Seems like it's about to stall? Those are usually symptoms of a bad fuel pump.

In the interim try clearing the codes and running a tank of premium.

 

[Paddy]

@***** My truck's got about 200K km on it, so like yours there's a lot of idle time and resulting fuel pump run time. Looking around on some other forums it is highly possible that the sensors themselves have gone bad and having them replaced cleared out the issues for those people.

Are you noticing the truck running rough? Seems like it's about to stall? Those are usually symptoms of a bad fuel pump.

In the interim try clearing the codes and running a tank of premium.

Aaron

Just seams odd both are "bad". I can throw parts at it but I'm an engineer and am always asking "why" something doesn't work.

I plan to replace the fuel pump in any case, I had a Suburban pump fail when on vacation and towing a boat! The lost vacation time and having to pay someone to replace the pump and having two tow trucks, is enough to convince me. Replace before they fail.

I suppose O2 sensors last just so long and bad or not, they could fail in the near future either way.

 

[CobraKing]

@***** - yes I agree that both going bad is odd. In my case it's just the one P015D and it seems to happen right after I fuel up at an 'unfamiliar' fuel station. Do try clearing the code and running 91 Octane to see if it might be a case of 'bad fuel'.

 

[swathdiver]

I noticed the fuel pressure at 43 psi but I have a flex fuel and not sure what the level should be. Regular engines should be 55 65 psi I recall.

My 2009 LC9 Flex Fuel engine calls for 43.5 psi and my pump always delivers 43 psi. Flex Fuel engines have larger injectors.

These P015X codes are referring to a bad sensor. I do not understand why people's scan tools have a letter at the end, these GM trucks do not use such codes, nor does the Tech2.

 

[Crockett]

Know this post is old, but wanted to add a notation for anyone who continues to get the P015B error after replacing the 02 sensor... like I did.

Check the flange between the exhaust manifold and downpipe towards the cat. GM uses a real thin flange gasket on the driver's side that will go bad. Mine was shot, and allowed exhaust to leak and thus trigger the P015B error and engine light even after replacing the 02 sensor and clearing codes.

The gasket was $5 from Advanced Auto... Replaced it, and no more code or engine light!

Also, be sure to run a "Drive Cycle," to clear any permanent DTC's (Diagnostic Trouble Codes that trigger the service engine light). Post 2010, new laws required these "permanent" codes so people could not pass emission tests by simply clearing codes with an OBD2 scanner tool or by disconnecting the battery. Now, you literally have to teach your vehicle that a repair has been completed- and this is done by doing a specific "Drive Cycle."



To perform a Driving Cycle do the following:

1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
4. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
6. Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
7. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

 

[jamesjiayu]

I'll try it. Thank you

 

[rdhogg]

Good information Crockett, I was getting a P015 "Check Engine" code about once a month on my 2013 Tahoe with 148,000 miles, and thought I would check Mr. YouTube and the Tahoe Forum. Seemed pretty straight forward and not a huge project. I ordered up the parts ( OEM ) from RockAuto a, the o2 sensor socket loaner from AutoZone, some Tesa High Temp wire harness tape left over from another project ( I had it why not use it). I went ahead and did both upstream o2 sensors. I have not seen any issues from the downstream sensors as of yet. I did bank 2 first because it is the most difficult to get to, and I had already put Penetrating Oil on both the night before. They did not look rusted but a little prep work can’t hurt. Start to finish about an hour and a half, done (it was 95 in my garage and had a couple of fans going so it was tolerable). The bank1 did not look bad but it was throwing the code so something was bad about it. The harness tape dressed it up, even though no one will ever see it. The loaner tool was new from AutoZone, so I cleaned it up and returned it the next day.