Fault code 1126 & 1133

[faperry]

2000 Boxster 2.7, 5 speed. 7.2 DME. The car has 38,000 miles was purchased new and all maintenance has been preformed by the dealer including a recent 30,000 service. The check engine light came on and we pulled the codes. P1126 and P1133 (Oxygen sensing adaption, lower load range, bank 1 & 2) We then removed the MAF and spray cleaned the entire part and reset the check engine light. After driving about 50 miles the light came back on, we disconnected each O2 sensor and spray cleaned the contacts, reconnected the leads and reset the light. After driving around 50 miles the light is back on. My sense is the o2's are ok and something else is triggering the fault code. Anyone have any suggestions as to the path to check likely items that would yield codes 1126 & 1133?

[Loren]

Your DME can not make the mixture rich enough (it sees too much air).

Potential causes:

– Incorrect signal from MAF sensor

– Intake air system leaking

– Fuel pressure too low

– Volume supply of fuel pump too low

– Fuel injectors fouled

I would start with the MAF. Since the problem indicates both sides of the engine - it is likely getting a bad MAF signal.

You can try cleaning it - but may need to replace it.

[faperry]

Thanks Loren,

I will replace the MAF

[faperry]

Thanks Loren,

I will replace the MAF

Update on the MAF replacement: After the replacement the car ran better immediately! now with about 400 additional miles it continues to be flawless. Many thanks to Loren for his timely advice.

[Loren]

:thumbup:

[rprieto]

Thanks Loren,

I will replace the MAF

Update on the MAF replacement: After the replacement the car ran better immediately! now with about 400 additional miles it continues to be flawless. Many thanks to Loren for his timely advice.

Was you car running rough while throwing P1126 and P1133 codes? After installing a new MAF Sensor, my car ran worse and I went from P0102 (MAF) to P1126 & P1133. I'm thinking the new one is bad.

Edited December 4, 2008 by rprieto

[1schoir]

Thanks Loren,

I will replace the MAF

Update on the MAF replacement: After the replacement the car ran better immediately! now with about 400 additional miles it continues to be flawless. Many thanks to Loren for his timely advice.

Was you car running rough while throwing P1126 and P1133 codes? After installing a new MAF Sensor, my car ran worse and I went from P0102 (MAF) to P1126 & P1133. I'm thinking the new one is bad.

Did you buy the new MAF on eBay? Lots of members have posted that they have bought defective MAF's both from eBay and from other disreputable sources.

Your new codes may indeed indicate bad MAF.

Regards, Maurice.

[rprieto]

Thanks Loren,

I will replace the MAF

Update on the MAF replacement: After the replacement the car ran better immediately! now with about 400 additional miles it continues to be flawless. Many thanks to Loren for his timely advice.

Was you car running rough while throwing P1126 and P1133 codes? After installing a new MAF Sensor, my car ran worse and I went from P0102 (MAF) to P1126 & P1133. I'm thinking the new one is bad.

Did you buy the new MAF on eBay? Lots of members have posted that they have bought defective MAF's both from eBay and from other disreputable sources.

Your new codes may indeed indicate bad MAF.

Regards, Maurice.

Got it direct from Sunset. Found I did not lock down one of the air filter tabs. Car runs better and no codes... yet. New problem I hear is whistle sound at very low throttle. Been driving it around for 30 mins.

[RFM]

A slight whistling sound with very low throttle indicates a faulty AOS.

[DaemonRa]

Is there a DIY post that explains how to get to the MAF and throttle body?

[mikefocke]

There are web pages on both the MAF and throttle body

This index will link you to both

Link

Edited December 12, 2008 by mikefocke

[DaemonRa]

There are web pages on both the MAF and throttle body

This index will link you to both

Link

Awesome link. Thanks a bunch!

[vealie]

What a great thread, this has just saved me a visit to a dealership.

My 2001 S was giving P1126 and P1133 as well. I've not had the car long and my heart sank when the CEL came on. The dealership I bought it from didn't help much, 'it's only the emissions light, nothing to worry about'. 19 - 21 mpg (uk gallons) was something to worry about though! So I bought a code reader and did some research. After watching a couple of youtube videos I thought I'd have a go at cleaning the MAF sensor. So for £10 I bought a set of anti tamper torq sockets and some electronic cleaner. Yesterday was nice and sunny so I took the engine cover off and got the MAF out and cleaned without any issues at all. The car immediately idled better when cold and generally ran much smoother. This morning I was getting 29 - 31 mpg and no CEL light after 70 miles. So a new air filter and MAF are on order as a more permeant fix.

So thanks to all.

[vealie]

Update.

New MAF installed and the car runs and ticks over even better. Mileage has settled down at around 22 mpg whilst in built up areas and 26 on the motorway. So much better in traffic, before it didn't want to slow down, now it has the proper engine breaking.