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Discussion Starter · #1 ·
A few weeks ago I got a CEL on my '99 Boxster and the following fault codes read out on the OBDII reader-P1124, P1126, P0130 and P0150. I took the car in and a smoke and liquid test was done to determine if any intake leaks were occurring and none were present. The MAF was removed and cleaned and I replaced the K&N filter with an OEM filter and the intake box was cleaned out. The codes were cleared and I drove for a few days and the CEL came back on again this time with the following codes-P1124, P1126, P0410 and P1411. The shop I use wants to do another smoke test and basically start at the front of the car and test all the way back. I'm starting to feel like this is another wild goose chase like the one I just went through trying to fix the gas gauge needle that ended up with me spending almost $500, replacing parts that turned out to not be defective and the gauge still doesn't read full when I fill the tank. Does anyone have any experience with these codes and what was done to solve the problem. Your help will save me several hundred dollars in another test that may or may not solve the problem.:cheers:
 

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Cant help you on the codes but I had a fuel gauge problem once as well after the battery had died. The shop had to empty the tank and recalibrate it with a measured amount of fuel.
 

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not about codes...but most often when gas gauge doesn't read full...check to see if gas tank is truly filled or not...could be problem with the gas tank vent system...not unusual on any older car
 

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P0130 - Precat O2 Sensor Cyl 1-3
P0150 - Precat O2 Sensor Cyl 4-6
P1124 - O2 Sensing "Rich Threshold" Cyl 1-3
P1126 - O2 Sensing "Rich Threshold" Cyl 4-6
P0410 - Secondary Air Injection System "Signal Implausible" Cyl 1-3
P1411 - Secondary Air Injection System "Signal Implausible" Cyl 4-6

Afraid I can't help you with what this all means with respect to your car though . . .
 

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P0130 - Precat O2 Sensor Cyl 1-3
P0150 - Precat O2 Sensor Cyl 4-6
P1124 - O2 Sensing "Rich Threshold" Cyl 1-3
P1126 - O2 Sensing "Rich Threshold" Cyl 4-6
P0410 - Secondary Air Injection System "Signal Implausible" Cyl 1-3
P1411 - Secondary Air Injection System "Signal Implausible" Cyl 4-6
Based on those one might say that the secondary air injection pump may have failed causing the system to run too rich, which would also bring a fault with the cat. Personally I'd start with consdering the first 4 codes as possibly being side affects of something else in the secondary air injection systems as they are codes from systems/sensors that come after the secondary air injection system.
 

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Based on those one might say that the secondary air injection pump may have failed causing the system to run too rich, which would also bring a fault with the cat. Personally I'd start with consdering the first 4 codes as possibly being side affects of something else in the secondary air injection systems as they are codes from systems/sensors that come after the secondary air injection system.
Secondary air injection system is only active during the first 30 seconds after a cold start. If that is the problem, while it is registerng fault codes, unlikely it will cause any issues while driving.
 

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Secondary air injection system is only active during the first 30 seconds after a cold start. If that is the problem, while it is registerng fault codes, unlikely it will cause any issues while driving.
Correct it is for the first 30 seconds, but as the OP did not mention that the codes came on when driving or not it is posible it is something up with the secondary air injection pump and it is only a start up fault which is being logged.

I would expect the first 4 codes relating to the rich running to be codes created when on the move and would be seperate from the secondary air injection, but knowing that the air injection system is there to weaken the initial start up fuel air mixture is a point that shouldn't be overlooked.
 

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Discussion Starter · #10 ·
After the third smoke test on my car one of the culprits were finally found a small $18 rubber hose part that is a part of the air/oil separator system. Cost for diagnosis, part and repair $266. I've learned a lesson to not assume anything about fault codes as they do not necessarily point to a specific part but an entire system. I still have to deal with the secondary air flow issue but for now my car is no longer running lean. Here's a pic of the part that had a small hole in it causing an intake leak. The part had to be cut off so that is why it appears in three sections, the leak was a pinhole.
 

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its been my read that an intake leak points to AOS /bellows as the first thing to check
 

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the AIR is like a mini leaf blower,when you first start the car the ECM commands it to pump filtered fresh air into the exhaust system in from of the o2 sensors it then [ecm] looks to see how active the sensors are [health] you need a scan tool that can run that test....basic stuff...the hoses that come and go to the pump,exhaust check valves,. ive seen GM cars pop a cel for the AIR system when a K/N filter was put in but calm down after a few hundred miles....todays cars demand a very good scan tool and the car maker to provide the data...which po doesnt believe in....somewhere there should be a vac/emission decal showing the various componets of the AIR system
 

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Discussion Starter · #15 ·
the AIR is like a mini leaf blower,when you first start the car the ECM commands it to pump filtered fresh air into the exhaust system in from of the o2 sensors it then [ecm] looks to see how active the sensors are [health] you need a scan tool that can run that test....basic stuff...the hoses that come and go to the pump,exhaust check valves,. ive seen GM cars pop a cel for the AIR system when a K/N filter was put in but calm down after a few hundred miles....todays cars demand a very good scan tool and the car maker to provide the data...which po doesnt believe in....somewhere there should be a vac/emission decal showing the various componets of the AIR system
Thanks extanker, I understand how the system works and what the components are but was trying to narrow down the parts of it that typically fail but I guess there really is no way of doing that without testing the whole system. Would that be a vacuum test to se if the valves are closing and or the vacuum reservoir is cracked? I did have a K&N filter on the car for 7K mi. but have removed it for an OEM. It's probably a stretch to think it had anything to do with it.:cheers:
 

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Anyone any ideas what makes an "implausable signal" is in regard to the secondary air injection pump, because I believe you can remove teh pump without any codes, so how is this code generated.

It's good they found the air link, but it sucks that such a cheap part costs so much, relatively, to fix, but that's the way it goes. That's why it's generally easier to be a tuning shop than a repair shop ;)
 

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Discussion Starter · #17 ·
Anyone any ideas what makes an "implausable signal" is in regard to the secondary air injection pump, because I believe you can remove teh pump without any codes, so how is this code generated.

It's good they found the air link, but it sucks that such a cheap part costs so much, relatively, to fix, but that's the way it goes. That's why it's generally easier to be a tuning shop than a repair shop ;)
My take, on the secondary air pump system, is it comes on at first start up to pump air into the cats so they heat up faster. The pump runs for about 20 secs. and the O2 sensors are reading the pre and post mixture in a set of parameters and that signal is sent back to the ECU. If the signal, from the O2 sensors, falls outside the parameters for a certain number of cycles (I believe two) then a fault code is sent to the ECU where it is stored and eventually will lead to a CEL. What makes it confusing, and expensive, is you don't know, even if the fault code is a secondary air system code, if it is the secondary air system or a bad O2 sensor. That's why the system has to be tested instead of the individual parts to narrow it down to a specific part (s). The system on my '99, although sophisticated for its time, is old technology today. I'm curious about the new Boxster's ECU system and if it is more part specific and less system generic.
 

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i can fire up my scan tool and look to see what tests can be done...be advised po gives away data to few...do you have use of a hand held lab scope /scanner....AIR tests want the rate at which the o2 sensors react/some tester let you view all 4 sensors/crossover counts/min,max values
 

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Discussion Starter · #19 ·
extanker thanks for the offer but I don't own a scan tool at this point as it is a violation of my lease where I live to work on cars so I'm pretty much at the mercy of shops. My concern now is that I now have a very strong gasoline smell coming from the back of the car at cold start up. God only knows what it is but at this point if it catches fire and burns up it might be a blessing.:beer:
 

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Bad to the Box, I know what the secondary air system does, but was wondering if anyone knew exactly how an implausible signal is associated to the air pump itself.

If you're getting a strong smell of fuel on start up then as I said before the codes for the cats and O2 sensors are most likely the result and you need to look at the secondary air injection system.
 
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