P0153 and P0174. No other codes or symptoms.

[RogerB]

I'm assuming this is just a bad O2 sensor. I'm only showing lean on the one bank, and the car runs OK. Just over 80k, and I'm pretty sure this is the original O2 sensor in this location.

I'll check for the obvious cracked or loose hoses, but I doubt it's major. Anyone care to comment? Sanity check?

FWIW, I searched, and didn't find this exact combination of codes. (A lot of posts where guys were throwing 7 or 8 codes including these two, or were lean on both banks, indicating a UIM gasket leak or something.)

Thanks.

 

[RogerB]

So, I guess my question is, are these two items related, and if so, which is causing the other?

Can the causes of the 174 (too lean on bank 2) lead to the 153 (slow response on sensor 1, bank 2)? Or is it the other way around?

 

[Tony2005]

Change the Bank 2 Upper O2 sensor. Remove oil filter for better "swing arm" room. Need 22mm or 7/8 inch or O2 sensor removal tool.

 

[RogerB]

Change the Bank 2 Upper O2 sensor. Remove oil filter for better "swing arm" room. Need 22mm or 7/8 inch or O2 sensor removal tool.

Thanks, Tony.

So, do all the "OE Type" sensors come with the modular connectors? (Specifically, Bosch)

Any reason to pay more for the Motorcraft sensor?

MC, $83 (Fordpartsonline)
Bosch, $60 (Autozone)

TIA.

 

[FavoriteMystaque]

Try here the Motorcraft is much cheaper http://www.rockauto.com/catalog/x,carcode,1106424,parttype,5132 You are lucky the bad sensor is the one in front My bank 1 sensor went bad, same mileage, very hard to replace, may be easier on a 96.

 

[RogerB]

Try here the Motorcraft is much cheaper http://www.rockauto.com/catalog/x,carcode,1106424,parttype,5132 You are lucky the bad sensor is the one in front My bank 1 sensor went bad, same mileage, very hard to replace, may be easier on a 96.

Thanks! Only $63 for the Motorcraft from Rock.

 

[Tony2005]

....So, do all the "OE Type" sensors come with the modular connectors? (Specifically, Bosch)
....

TIA.

What you should avoid are "universal" sensors. Those are usually the ones without the connectors and you have to splice the wires in.

 

[RogerB]

Replaced sensor, now have lean on both banks

Replaced sensor, now have lean on both banks

P0171 and P0174.

Interesting progression, here. I'll try cleaning the MAF, next, and then inspecting my vac lines. At least I've made progress.

I think I have a small exhaust leak, but it's after the downstream sensors. Could that throw the lean codes?

A word about Rock Auto. Outstanding.

I ordered my Motorcraft sensor at 12:22 pm on Wed, normal ground shipping, and had it in hand by COB Thursday. Shipped from TX to KS.

 

[Tony2005]

P0171 and P0174.

Interesting progression, here. I'll try cleaning the MAF, next, and then inspecting my vac lines. At least I've made progress.

I think I have a small exhaust leak, but it's after the downstream sensors. Could that throw the lean codes?
....

Yes. The last time I had P0171 and P0174 together, one of my vacuum hoses were broken.

 

[RogerB]

Cleaned the MAF, now P0174, P0420, P0430

Cleaned the MAF, now P0174, P0420, P0430

Just to document the progression, here.

I cleaned the MAF and now I'm still getting the P0174 (Lean on bank 2).

Added P0420 and P0430 (Catalyst system efficiency, both banks).

I'm checking TSBs and searching, etc.

My next step is to check for vac leaks and fix any that I find. Then I'll see if the cat codes come back.

 

[Tony2005]

Your lean codes P0171 and P0174 lead to P0420 and P0430. Need to fix problems causing the lean codes ASAP. Or time for mileliminators for the P0420 and P0430.

 

[RogerB]

Your lean codes P0171 and P0174 lead to P0420 and P0430. Need to fix problems causing the lean codes ASAP. Or time for mileliminators for the P0420 and P0430.

Tony,

I suspected the lean condition might be leading to "false" 4xx codes.

Are you saying the causes of the P017x codes might actually damage the cats?

I might not have time to look at this myself until this weekend. Would you recommend I act sooner?

 

[Tony2005]

...Are you saying the causes of the P017x codes might actually damage the cats?
....

Yes. Instead of running normal, the engine is running on a set of predetermined numbers ("limp" mode) and it is running richer than what it should be.

Assuming there is unmetered air going in to the system, the PCM is leaning rich until it reaches a limit and then turns on the lean code. Then it runs in limp mode.