P1152, Lack of O2 switch, sensor indicates rich

[Colt45ws]

Bank 2 Sensor 1
Quote:
A HEGO sensor indicating rich at the end of a test is trying to correct for an over-lean condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.

Ive had this code pop twice now. The first time I cleared it and now its back. Ive looked at the fuel trims for both banks and they are excellent. Under 5 or 6% correction. Ive also datalogged the O2 sensor in question and didn't see anything out of the ordinary. So intermittent.
Both times it happened just a minute or two after startup.
I have a pair of O2 sensors with 6000 miles on them, so they will be going in the car tomorrow to eliminate the 200k mile originals.

 

[Trav]

Did you check the exhaust manifold for a broken stud(s)? Might as well start simple.

 

[Colt45ws]

It doesn't sound like it, but Ill be in there to replace the O2s so, Ill look everything over and make sure its good.

 

[Colt45ws]

Whoopsie! It was actually P1151, which is the same but lean. So since both times it happened just after startup I setup for datalogging before I started the car from dead cold.
What I found pretty much solves it.


Very cold blooded sensor. Bank 1 was ready and started switching after 15 seconds. Bank 2 took over a minute. So I think replacement of the sensor will solve this one.

 

[Trav]

It sounds like you found it.

 

[Colt45ws]

I forgot to screenshot the after, but yeah, replacing them fixed it.
Bank 2 was hot in 15 seconds and bank 1 in 20.

 

[Trav]

Probably a failing heater, most of the time they just fail and throw a heater code so its a bit unusual.

 

[Colt45ws]

Yeah, I was trying to think of why it would do that, take forever to warm up, unless the heater wasnt working. But, then where is the code for bad heater? It still mustve been sinking some current and the lower threshold in the PCM is too low to diag this particular circumstance.