P1275 Cel?
 

I have been chasing a P1275 CEL code that I started getting when I put headers and 100-cell cats on the car. I replaced all 4 oxygen sensors at the same time that the headers/cats were installed.

Shortly after the installation I started getting the P1275 CEL code, which pointed us to low efficiency from the cats or oxygen sensors. We first checked the oxygen sensor wiring and it seemed to check out fine.

BTW, the car has had the CPU reprogrammed to take into account the headers and high-flow cats. The last time we looked we got the P1275 and it said the left bank was running at low efficiency. We then swapped both pre-cat and post-cat oxygen sensors on the left and right side and again got the P1275 saying the left bank was still bad.

That made us think it was a bad cat on that side, so we replaced the cat on that side last week, and again got the P1275 CEL, any ideas on what might be going on would be greatly appreciated,

Ed

:(

My guess (which is a good one) is that o2 sensors are experiencing large amounts of unburned fuel and or heat which headers and high flow cats usually will cause. Simple fix is to buy an Anti-Fouler from auto parts store which can fit your O2 sensor and thread into your header/exhaust system...

Drill a larger whole into the anti-fouler so that the head of the o2 sensor can thread all the way into the anti-fouler.

By installing this, you will be setting the o2 sensor back a bit out of the way of all the heat and gases and will likely eliminate your CEL issue.

I had to do this to my friends Acura RSX Type-s cause he bought a Header kit that eliminated the cats. The after-cat sensor required the anti-fouler in order to keep the CEL by O2 errors away.

I think you might be chasing the wrong things.

The generic meaning of the OBDII P1275 code is:

P1275 Accelerator Pedal Position (APP) Sensor 1 Circuit

Since his car is MY00, his OBDII codes are different than 97-99 OBDII codes

for him MY00, P1275 is - Ageing of oxygen sensor ahead of TWC, bank 1

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Edit:
Actually, even for MY97-MY99
P1275 is - Aging of Oxygen Sensor Ahead of Catalytic Converter (Cylinders 1 - 3) - Below Lower Limit

Which means they are basically the same from MY97 - MY04

So clear this up for me... when was the change to OBDII? Aren't all OBDII codes universal, thus the OBDII standard? Is his car OBD (I) not OBDII?


I'm confused.

They are both OBDII, but on renntech.org, they have 2 different OBDII sections... one for MY97 - MY99, and one for MY00 - MY04 so i assume the P codes might differ slightly. In your case, its the same error message either way.

Hi,

Nope. The OBDII Codes are a Standard created by the SAE (Soc. of Automotive Engineers) - they are the same. They are properly referred to as DTCs (diagnostic trouble codes) and are all 5-digits.

Within this mandated Standard, a Manufacturer has the ability to set proprietary codes or sub-codes, meaning that a generic DTC can have multiple meanings albethey related. The 1st digit identifies the type of code. There are 3 variations: 'P' (Powertrain), 'B' (Body) and 'C' (Chasis). A 'P' code means that it is powertrain related.

The next digit identifies the DTC as either an SAE code or a Manufacturers proprietary code or FCs (Fault Codes). This will either be a 0 - SAE or 1 - Porsche specific code - FC.

The 3rd digit refers to a specific System or value within the DTC type. 0 -Total System. 1 - Air/Fuel Induction, 2 - Fuel Injection, 3 - Ignition System or misfire, 4 - Aux. Emissions Control, 5 - Vehicle Speed/Idle Control, 6 - ECM Input/Output, 7 - Transmission.

The final digit refers to a specific component or condition within the defined System.

So, the code P1275 means: P Powertrain, 1 Porsche subcode, 2 Fuel Injection, 5 Pre-catalyst O² Sensor, Bank 1-3.

Now, the software version of the ECU (DME in Porsche Speak) allows for greater/lesser subgroups based on it's sophistication and memory. Version 5.2.2 allows fewer specific parameters than does version 7.2 or 7.8.

To read these subgroups, you need a Porche specific code reader (PST2 or PIWI). But, several lists of these codes are available through any number of sources such as the Workshop Manual or the Bentley Service Manual.

Code P1275, Posche FC 16 for Bosch Motronic 7.2, indicates that this is an aging O² Sensor on Bank 1-3. Clearly, this is not the case, You have now reached the limit of what the onboard diagnostics can tell you. So one must look at why the DME is indicating this fault or why the sensor itself is emmulating an aging sensor.

My intuition and awareness of past similar problems tells me that the most likely (but certainly not the only) possible cause is that the pre-cat and post cat sensors are not properly spaced apart, or that the new Cat is incapable of flowing as well as advertised. Long distance diagnosis is difficult at best, but this is where I'd start. Hope this helps...

Happy Motoring!... Jim'99

Since the problem is only on one side of the engine, try putting the left O2 sensors on the right and the right ones on the left. If the code stays on the same side, the problem is not the sensors. If the code moves with the sensors, it's them. Then, if that's the problem, I'd try swapping just the sensors in front of the cats and seeing what happens to the code. If it moves, the problem is the front sensor. If it stays put, it's the rear.

"Since the problem is only on one side of the engine, try putting the left O2 sensors on the right and the right ones on the left. If the code stays on the same side, the problem is not the sensors. If the code moves with the sensors, it's them. Then, if that's the problem, I'd try swapping just the sensors in front of the cats and seeing what happens to the code. If it moves, the problem is the front sensor. If it stays put, it's the rear."


Good idea to swap the sensors from side to side, we did that and when we did it said the same side was at low efficiency, that is why we put in a new cat on that side, but we are still getting the same error code.

I think Jim's idea about the height and spacing of the oxygen sensors is where the problem actually is.

Ed

:cheers:

P1275
 

Is it possible that these codes are just a reflection of the fact that ethanol has been added to the fuel since the cars were manufactured?

No.......................

I am having he exact same problem only I have not had the PCM reprogrammed. I have the old pre cat sensors in place and have yet to swap in the new ones. I had assumed it was the old sensor but your thread here has me worried. I will get on swapping those sensors this week.