Input and advice needed! - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Well a couple of weeks ago my CEL came on and it read P1123 and P1125 and I cleared it with my OBD II Reader. During the time the light was on the car would hesitate eveyr once and awhile when I gun it. I was advised to clean the MAF which I did and the hesitation hasn't happened since. 55 Miles later the CEL light comes on with P1123 and P1125 again,but the throttle response is the best it has been with no hesitation at all. Is it normal for the CEL light to come on again with the same codes? Should I clear it or take it to a pro shop to deal with it?

Hi, How are you retrieving the Codes? Are you using a Digital Readout or counting the Flashes? What scanner are you using? Are you certain there's not a typo in your post? The reason I ask is that P1123 is not a valid DTC Code for the Bosche DME 5.2.2 - '97-'99. I suspect your DTC Codes are P1125 and P1132 . These are upper Range load O² Sensor Fault Codes. They may not have been properly reset the first time, or may actually be faulty. In any event, both Codes signify a possible Lean Condition on each Bank and that's not a good thing. The mileage you achieved since cleaning the MAF means little. The DME will not send a MIL (Malfunction Indicator Light - pretty much same as CEL) until it has stored the same Fault in two consecutive Complete Drive Cycles. A Drive Cycle is a set of Parameters of Vehicle Speed, Engine (Oil ) Temperature and Time and must be met before a MIL is indicated. A Generic Federal OBDII Drive Cycle states the Vehicle must Start Cold and Idle for 2min. 10sec., then Accelerate to 20-30MPH and hold steady for approx. 3min. 15sec., then Accelerate to 40-60MPH and remain steady for approx. 15min., then Decelerate and come to a Complete Stop and Idle for approx. 5 min. Porsche's Proprietary Drive Cycle will be EXTREMELY similar - BY LAW! If a second Complete Drive Cycle is not completed, the fault will remain stored until a 3rd Drive Cycle is completed. This may be waived as it is a possible Emissions Fault. In addition to this, the Bosche 5.2.2 contains Diagnostic Montior Software which monitors Signals from, and operation of, various Components. It uses 3 criteria to determine whether the component is at fault. These are: a.) Short to Ground, b.) Short to Battery + and c.) Component Missing or not functioning (Open Circuit). The DTC Codes you claim indicate these criteria being met. So, while the MAF may be masking their symptoms, you may actually have faults in these components too (possible, but too coincidental for me to believe it). My recommendation would be to disconnect the Battery for 5 min. (Have your Radio Code and disconnect the Neg. (-) Terminal 1st), then reattach the Battery. Hope this helps... Happy Motoring!... Jim'99

I am using my Actron OBD II Pocketscan. I ran it again and it read P1123 and P1125 again. I have the radio code and will disconnect the battery in the morning and drive it for awhile and see what happens.

Hi, Interesting about the Actron. It would seem to have incorrect codes for Bosche DME M 5.2.2 -'97-'99, or is coded specifically for Bosche DME ME 7.2 - '00-'06. There is no P1123 Fault Code for Bosche DME M 5.2.2, but there is a P1123 for Bosche DME ME 7.2 which reads as: O² Sensing, area 1 cylinders 1-3 , but the corresponding code for Bosche M 5.2.2 is P1125 which reads as : Oxygen sensing adaptation, upper load range, cylinders 1-3 . Code P1132 for Bosche DME M 5.2.2 reads as: Oxygen sensing adaptation, upper load range, cylinders 4-6 . Assuming that a bad MAF would trigger an O² Fault Code, it should trigger both cylinder banks 1-3, 4-6 simultaneously, and you are getting two codes, albeit improper ones. If Battery disconnection doesn't clear the fault, you may have a Failed, rather than Contaminated MAF Sensor. It may also be possible that you didn't properly seat the MAF Seal and it's leaking Air, similar to the Doughnuts on my old Europa. There's some merit to my reasoning about the seal, because when you add Air without adding more Fuel, you run Lean. If the MAF is sensing the Air passing past it and signalling this to the DME, and then additional Air is introduced which the DME does not know about, it meters the Fuel based on a lesser quantity of Air and you're running Lean. You want to stay with this until solved because a bad A/F mixture can cause all sorts of issues, especially if running Lean. I once had a Lotus Europa which used Rubber Doughnuts as insulators for the Carbs to keep engine vibration from foaming the Fuel in the Float Bowls. I was tracking the Car and didn't realize that one of these was leaking, adding Air which the Carb didn't compensate for - my Buddy had leaned on the Carbs when helping me time the motor and accidentally pinched the Doughnut to where it broke it's seal. The Mixture ran so Lean that I burned a hole in my #3 Piston in about 6 Laps (and these were Steel Pistons, not the Alloy ones used in the Boxster). A Car will usually run best when running Lean, so I am concerned by your comments about how well the Car is running. Avoid running it excessively hard until you get this sorted. Hope this helps... Happy Motoring!... Jim'99

Well my car has 53k on it now with the original MAF so ordering a entirely new unit has crossed my mind before as I know they tend to fail in Boxsters. I will give Suncoast a call tommorow but I do not think they can beat $246.77 per MAF(non e-gas) from Arizona Auto. I will not let the RPMs build up for awhile till I can find out what going on for sure. MNBoxster as far as you know all indications point to the MAF correct, and not the oxygen sensors or what else could trigger those codes?

Hi, Well, the only codes you're pulling are O² codes. The MAF Codes for the Bosche M 5.2.2 are P0102 (short to Ground - upper limit - Rich mixture threshold). Now a malfunctioning MAF will cause problems downstream with, and possibly trigger, the O² sensors. There's some history of this. The difficulty is that we don't have the resistance values for the O² sensors and so these are not easily checked. MAF sensors do fail somewhat notoriously, especially the early ones. But, so do O² sensors (although with less frequency, but at 50k mi., anything could happen) and these can cause real drivability issues with the values they send to the DME. One could easily misdiagnose one as the other, especially with all the recent chat about faulty MAFs and K&N Filters. But, the odds of both Banks of O² Sensors going at the same time is unlikely, very unlikely. I'm still thinking MAF. Check the MAF Seal as I suggested, disconnect the battery, try to reset again with your tool, and then reassess. It could be as simple as your Actron not being able to reset the fault - we already know it does not have all the proper codes for M 5.2.2. Hope this helps... Happy Motoring!... Jim'99

OK,well I tried to reseat the MAF and disconnected my battery. The CEL light cleared as it should and I started it up twice and let it run for awhile,no CEL but the idling was high,around the 900-950PM area for the first start and more around the 900RPM on the second start.

I was advised to remove the MAF harness from the MAF and see if I could get other codes to pop up besides the O2 sensor codes. Codes P0102 and P0112 came up, and not the O2 sensor codes. Sounds like my MAF has gone bad.

Hi, Those two Codes are exactly what you Should Get when disconnecting the MAF, that would not be abnormal. It reports an Open Circuit which indicates that there is no MAF hooked to the System. The MAF would definitely be Bad if you had it connected and still got those two codes. You may still have an underfunctioning MAF, but those Codes alone don't justify replacement, especially at $200+. Try to drive the Car a day or so and see how it behaves... Happy Motoring!... Jim'99 PS Was this Test with the Car running? The O² Sensors have to be up to Temp to test them.

MNBoxster yes the car was running when I had the MAF disconnected. I ran it for about 10 minutes without it the O2 codes never came on even when I revved the engine and restarted it. The moment I went to move the car out of the driveway the P0102 and P0112 codes came on. I would think that if it was really the O2 sensors doing then shouldn't those codes have come on along with the open circuit codes? I connected the harness to the MAF and put everything back together for the night,its too dark to continue to troubleshoot.