Trouble Codes 1128 and 1130

[SpeedRacer350]

My check engine light came on and I pulled two codes:

P1128 Oxygen sensing adaptation, idle range, bank 1

P1130 Oxygen sensing adaptation, idle range, bank 2

I don't think it's as simple as a bad O2 sensor- especially since it's both of them at the same time. I've read on other forums where codes like this can indicate a bad MAF sensor.

I do get this problem after I drive the car about 5 or 6 miles. It used to happen every few months, but now I've got it twice in the past week.

I really don't want to start swapping parts in hope of fixing the problem. And I really don't want to take it in for service. I just paid $750 to have the coolant expansion tank replaced. My wallet is still aching from that one. But I'd be glad to swap the MAF as long as I have some comfort level that it is truly the problem.

Also, I heard a rumor that the emissions system is warranted for 7 years. I no longer have my warranty book, so I can't verify this. Is that true?

My car is a 2000 C2 Coupe 6 spd.

Any advice would be greatly appreciated!

[Loren]

If P1128 or P1130 (oxygen sensing at rich threshold) is stored in the memory, this means that the fuel/air mixture is too lean.

Air leaks ahead of the oxygen sensors can lead to a fault in adaptation. Check exhaust system for leaks. Check for air leaks in intake air system.

If nothing obvious there then we need see your MAF readings.

[gcp]

If P1128 or P1130 (oxygen sensing at rich threshold) is stored in the memory, this means that the fuel/air mixture is too lean.

Air leaks ahead of the oxygen sensors can lead to a fault in adaptation. Check exhaust system for leaks. Check for air leaks in intake air system.

If nothing obvious there then we need see your MAF readings.

<{POST_SNAPBACK}>

Also make sure your air filter is in good shape. A dirty filter can cause all sort of bad readings.

I plan to do the expansion swap myself when I get home, hope I can do it with not too much pain.

[dtschroe]

I had the same exact DTCs (P1128 & P1130). Actually, started with just a P1128 and eventually both (I suspect the sensitivity of the O2 sensor in the one bank was higher than the other). Checked for leaks, as Loren suggested in a previous posting. Found none. Ordered a MAF sensor from Sunset Imports for about $270. Changed it myself in about 10 min. (you'll need a T20 security Torx socket that can be purchased at various auto parts stores for about $10). Problem fixed. Haven't had CEL for over 600 mi. now. I use to get a CEL about every 100-200mi (sometimes sooner depending on driving habits). Also, idles much smoother now.

[SpeedRacer350]

Wow, thanks for the great information. I'm feeling pretty good about blaming the MAF now. :cheers:

I'm new to this forum and really like it so far. There's some good info here that's hard to find.

Word to GCP- Be careful doing that coolant tank swap. You have to be sure to bleed the system correctly or you can get air pockets in the head and seriously damage your engine. At least this is what I've heard.

I'll order a MAF soon and keep you all posted to how it turns out.

[gcp]

SpeedRacer350, thanks for the tip!!

And BTW you know the MAF can be cleaned right? And even though I've not done it I would try that first if I needed to.

[SpeedRacer350]

Thanks for the info. I think I'll try to clean it with electrical contact cleaner while I have it out to see the part number.

One more question though: What part number should I get? I'm finding several available. At first I thought I'd get the latest one, but I then heard I might have to reprogram the computer. I definitely don't want to do that. What do you guys think?

996 606 123 00 - original - Bosch PN B3130-70627

996 606 124 00 - update 1 - Bosch PN B3130-128499

986 606 125 00 - update 2 - Bosch PN B3130-149265

Thanks.