The Error code 28 Plague

madfronter · 06-15-2006, 10:49 PM

Is anyone else plagued with the catalyist efficiency code? I have been trying to put an end to this issue for months. I've replaced my cat, both O2 sensors, charcoal canister, ignition wires, valve cover gasket, exhaust, coil pack and nothing has helped in resolving the issue. The car runs fine but the code comes on every couple of days and it is really frustrating me. I have the bavauto fault code reader so I can turn the light off but I want to resolve this problem. Anyone else having this problem?

DustenT · 06-16-2006, 12:01 AM

YOu might try replacing your thermostat. if the car runs too hot, you will get that code.

roadrash · 06-16-2006, 01:41 AM

I don't know how Error 28 compares to the one I had (P0420 - Catalyst Efficiency Below Threshold - Bank 1), but it sounds similar. Read more here.

Short answer: I agree with Dusten, check your thermostat. One sign of a bad thermostat is that your temperature needle doesn't go to the center of the range and stay there. It may fluctuate between cool and hot, or it might stay steady, but not stay at the center of the range.

madfronter · 06-16-2006, 02:57 PM

Thats something I wouldn't have thought of. My car has been running a little cooler than normal lately. My temp normally would sit in the middle but it has been fluctuating and reading cooler than normal. Thanks for the input, I'll try replacing the thermostat.

fourbysix · 06-16-2006, 03:08 PM

should my temperature gauge needle be resting in the middle of the gauge pointing straight up once my car is "up to temp"

roadrash · 06-16-2006, 03:13 PM

According to my mechanic, the temp needle should move to the vertical position as the engine warms up, and then not move. Keep in mind that because you're looking at the gauge from left of center, the needle will appear to be just a bit right of center.

madfronter · 09-28-2006, 07:54 PM

I replaced a few more things and they didn't do jack **** to help with the code plague.I replaced the spark plugs a couple weeks ago and the thermostat about 1-1/2 months ago and and code 28 from chart 7 "catalytic efficiency" code is still making my CEL light up. Does anyone have any other suggestions? I am getting really annoyed with this situation and would like to resolve sooner than later.

roadrash · 09-28-2006, 08:57 PM

Are you sure that the new thermostat is working properly? The first replacement on mine went bad in a few weeks and the temp wouldn't ever get up to the center of the gauge. So, that kept causing the same error. Keep an eye on your temperature gauge and let us know what it's doing.

After the second thermostat replacement the temperature would stay steady in the center of the gauge. But, I still occasionally got the P0420 error code. Once I started shopping for a new catalytic converter, the CEL went away. Apparently, after a set number of drive cycles, the OBD system decided that things were OK. And naturally, since I mentioned this, the CEL will come back in a day or so. LOL

I wish I could be of more help, but I'm not a mechanic and we've pretty much reached the limit of my personal experience with this specific situation.

JMJ

madfronter · 09-28-2006, 09:36 PM

Quote:

Originally Posted by roadrash

Are you sure that the new thermostat is working properly? The first replacement on mine went bad in a few weeks and the temp wouldn't ever get up to the center of the gauge. So, that kept causing the same error. Keep an eye on your temperature gauge and let us know what it's doing.

After the second thermostat replacement the temperature would stay steady in the center of the gauge. But, I still occasionally got the P0420 error code. Once I started shopping for a new catalytic converter, the CEL went away. Apparently, after a set number of drive cycles, the OBD system decided that things were OK. And naturally, since I mentioned this, the CEL will come back in a day or so. LOL

I wish I could be of more help, but I'm not a mechanic and we've pretty much reached the limit of my personal experience with this specific situation.

JMJ

Thanks for the response. I've been watching my temp like a hawk and it is in the center rite where it should while running.

madfronter · 09-29-2006, 03:00 PM

Does anyone else have any suggestions?

mohaughn · 09-29-2006, 04:06 PM

Have you thought about tapping into the wires at all of the sensors, measuring the reading while the car is running, then tapping into the wires at the ECU and seeing if there is a difference? This is really the reason that you should have a good mechanic with good tools doing the diag for you. It is very possible that you have a wiring issues that is causing the wrong data to get sent to the ECU.

Find someone who has a diagnostic computer(not a code reader) that can actually pull up the data that the sensors are sending out. It should be very easy to determine the problem by looking at the sensor outputs. And it probably would have been cheaper in the beginning than throwing all of those parts at the car.

madfronter · 09-29-2006, 04:17 PM

Quote:

Originally Posted by mohaughn

Have you thought about tapping into the wires at all of the sensors, measuring the reading while the car is running, then tapping into the wires at the ECU and seeing if there is a difference? This is really the reason that you should have a good mechanic with good tools doing the diag for you. It is very possible that you have a wiring issues that is causing the wrong data to get sent to the ECU.

Find someone who has a diagnostic computer(not a code reader) that can actually pull up the data that the sensors are sending out. It should be very easy to determine the problem by looking at the sensor outputs. And it probably would have been cheaper in the beginning than throwing all of those parts at the car.

You are right and have a great suggestion. I should have done this in the first place. I do like knowing that all the parts I replaced would have had to be replaced at some point anyway, so it doesn't bother me that I spent money to replace those parts and infact some of those things like the coils, spark plugs and wires resolved my missfire problem. So all in all I am happy that I have replaced all the things I did and I just want to figure out this code issue.

Thanks for the advise...

mohaughn · 09-29-2006, 05:32 PM

Yeah.. Most of that stuff is normal wear and tear anyway, so if it was at the end of their lifespan it is money well spent. About a week or two I posted a link that had information about how to probe the O2 sensors and understand what the readings mean via a multimeter. I'd post the link, but I can't find it and I'm at work so i didn't want to spend a bunch of time searching for it..

I think I googled for something like BMW Bosch O2 sensor volt reading. It is a good DIY article on troubleshooting emission related codes.

At this point I would think it is wiring since you have replaced just about everything else and the car is running properly, just throwing the code. Unfortunately I've never dug that deep into the car myself as most issues have been easily repaired with parts and I've not had any major wiring issues so I can't say for sure.

madfronter · 09-29-2006, 06:45 PM

Well I appreciate your helpful comments. I'll do a google search for that O2 sensor DIY. Thanks for the heads up.

Mad-Machine · 09-29-2006, 10:14 PM

see, I am pretty sure that my code really is for the cat. While she runs great when I give her throttle, my Ti has a very rough idle and you can smell the exhaust/fuel when you walk behind the car when she is idling.

I changed the wires and plugs.. old plugs were perfect.

.	Powered by site supporters vBulletin Version 3.8.8 Copyright ©2000 - 2024, Jelsoft Enterprises Ltd. Copyright ©1999 - 2024, 318ti.org © vBadvanced CMPS v3.2.2 [page compression: 115.17 k/138.26 k (16.70%)]
318ti.org does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information or products discussed.