Do I need 2 new O2 sensors?!

[mg911x]

I have a '98 Boxster 2.5 (US model) with the following CEL codes....I don't know what they mean and I'd like to go to the mechanic with a little info in my back pocket. Do I need new sensors? Thanks,

P1123 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold

P1125 Oxygen Sensing Adaptation Area 1 (Cylinders 4 - 6) - Lean Threshold

P1128 Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold

P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold

[mikefocke]

The pollution control circuitry consists of a sensor in the air intake (MAF) and ones in the exhaust (O2). I can't see two failures at the same time being probable so my suspicion would be something that can affect both sides of the engine. You can replace any of these parts yourself very easily. There are instructions online and parts cross references so you don't have to use Porsche branded parts but can use parts from the company that makes the parts and sells them to Porsche.

Any other symptoms beside the CEL and codes...like rough running under specific circumstances?

http://mike.focke.googlepages.com/mikespor...boxsterwebpages

[Loren]

I have a '98 Boxster 2.5 (US model) with the following CEL codes....I don't know what they mean and I'd like to go to the mechanic with a little info in my back pocket. Do I need new sensors? Thanks,

P1123 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold

P1125 Oxygen Sensing Adaptation Area 1 (Cylinders 4 - 6) - Lean Threshold

P1128 Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold

P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold

Are some of these old codes - and others are new codes?

It is not very likely that you would have both a too rich and too lean situation at the same time.

[mg911x]

Car runs fine as usual. Not sure if codes are old or new...CEL came on last summer but just getting around to it now. I've replaced 2 o2 sensors over the past 3 years so I assumed CEL was for the last 1 or 2 sensors.

[Loren]

Your O2 sensors are just that "sensors". They are likely fine.

Depending on your current fault code(s) you more likely have an air leak or bad MAF.

[mg911x]

Would you start with cleaning the MAF or just go to a shop? I don't mind spending the cash for a repair, but if a dirty MAF is the likely culprit I'm content to give it a go.

[Loren]

I would start by getting the current fault codes - report those here and we will tell you where to look next.

Without the fault codes everything is a guess.

[mg911x]

The codes above were obtained today.....

[Loren]

The codes above were obtained today.....

As I said it does not make sense to be both too rich and too lean.

Have them read with the Durametric software, or a PST2 or a PIWIS tester.

[mg911x]

As always, thanks for your advice!

[GPDRVR]

As always, thanks for your advice!

Getting the same codes my self 1123 and 1125 - had them cleared multiple times and keep coming back. 1999 Boxster 2.5.

Aurora Colorado....car runs great.

[Haulfron]

I have a '98 Boxster 2.5 (US model) with the following CEL codes....I don't know what they mean and I'd like to go to the mechanic with a little info in my back pocket. Do I need new sensors? Thanks,

P1123 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold

P1125 Oxygen Sensing Adaptation Area 1 (Cylinders 4 - 6) - Lean Threshold

P1128 Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold

P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold

2001 Boxster 2.7

This might help.

Got codes P1128 & P1130 today. Google search revealed that cause could be air leaks in inlet manifold after meter. Found join immediately after air filter box was loose due to corroded/broken clamp. Saved the cost of purchasing 2 oxygen sensors - although conclusion is a bit early as full flow test ;-) not carried out yet.

[Topless]

It is unusual to get both rich and lean codes at the same time. I suppose it is possible if the MAF sensor is going south and giving inconsistent readings from day to day. Try simply unplugging the MAF and go for a spin. If the car runs better, replace the MAF. Cleaning the MAF works sometimes but is often a temporary fix.