P0154 and P0134 pending?
 

Hi all,

I’ve been trying to get the car (99 2.5L) ready for smog and last time I took it it literally had the check engine light come on at the testing station! That code was EVAP related, and I think may have been related to the gas cap.

So I replaced the gas cap and went out to do the drive cycles. All the tests pass except EVAP which is still incomplete (not unusual for that one to take a while and CA allows one incomplete test).

However, I’ve also somehow picked up both P0134 AND P0154, which is an error about both pre-cat sensors on completely different sides, but they are only pending. The confusing part is that the O2 monitor just passed! How could the O2 monitor pass if the sensors were not working??

So now I’m wondering if they are spurious codes... I’ve never had them before as far as I recall, and not had to replace those sensors. For both to happen simultaneously, and for the car to have zero running issues (rock solid idle, etc), and have the O2 tests pass - must be a random pending code?

Just wanted to check with the community in case I’m missing something specific to this car. Really hope I can get this thing smogged tomorrow!

Thanks!

S.

P0134 and 0154 are codes for the interruption of signal from the O2 sensors on both banks. Usually, this is a wiring or connector issue.

Thanks! However, is it common for it to happen to two different banks at the same time when these codes have never been seen before on either bank? Just want to make sure there isn’t a common connection issue. I believe all four O2 sensors use a common rail, but then I would have thought I’d have seen 4 pending codes (unless it didn’t get a chance to show failures on the others before the wiring “corrected” itself).

Thanks!

S.

Well, passed smog today with no issues, and still no check engine light, so I guess the sensors are fine right now. Will keep an eye on it in future tho..