OBDII P1421, P1423 What are these ?

[HGS]

1997 328ic: My scan tool reads two codes related to the evaporative control system- P1421 and P1423. Can't find any info on these manufacturer specific codes.

I have the Bentley manual for my car but it doesn't seem to have any kind of code list for OBDII. I've also checked www.obd-codes.com and they don't describe these particular codes.

Can anyone tell me what these codes mean and most importantly what repair might get rid of them ? (I already replaced the fuel cap and made sure it is 'installed' properly)

[Robcast]

http://autorepair.about.com/cs/troub.../bl_obd_14.htm

[stuvx]

Check if your secondary air pump comes on when you first start your car and make sure the secondary air passages are clear.

[LinearX]

Your secondary air pump valve probably got jammed with crud, causing water to fill up the hose to the electric air pump. This probably made it squeal and howl when your car had just been started.

One day, the squealing went away, but the check engine light was on, right? You'll need a new secondary air pump and the valve that failed. It would probably be a good idea to replace the hose as well.

[HGS]

Thanks for the suggestions above, but the secondary air pump works OK and has never jammed, sqeeled or howled. I guess that gives me something to look forward to, eh ?

What actually happened was that for a long time I had a P0442 code (small evap fuel system leak) and finally had a BMW mechanic track it down. $350 later he found a crack in a hose connection on a purge tank in the rear fender well area and fixed it. When he did the P0442 code went away but it was replaced by the P1421 and P1423 codes. The link above defines P1421 as a secondary air system bank 1 problem. Anyone have an idea of what that means ? If it has to do with the secondary air pump why does it refer to bank 1 ? Also I still can't find out what the 1423 code refers to.

[LinearX]

Thanks for the suggestions above, but the secondary air pump works OK and has never jammed, sqeeled or howled. I guess that gives me something to look forward to, eh ?

What actually happened was that for a long time I had a P0442 code (small evap fuel system leak) and finally had a BMW mechanic track it down. $350 later he found a crack in a hose connection on a purge tank in the rear fender well area and fixed it. When he did the P0442 code went away but it was replaced by the P1421 and P1423 codes. The link above defines P1421 as a secondary air system bank 1 problem. Anyone have an idea of what that means ? If it has to do with the secondary air pump why does it refer to bank 1 ? Also I still can't find out what the 1423 code refers to.

The secondary air pump pumps both into the first bank (1-3) and second bank (4-6). When P1421 and P1423 appear simultaneously (Bank 1 is one code, the other is Bank 2), it means the secondary air pump as failed (it did on my car, anyway). There is a port on each bank where the secondary air pump pushes air into the exhaust manifold during startup (depending on ambient temperature) to reduce emissions.

[328 Power 04]

u can always check the vaccum lines that lead to the air pump... if theyre broken it wont start up

[pfd964]

if the 2ndary air pump is working properly and you remove the hose from the air box, you should feel suction, correct? So if you don't, the pump has failed correct? If it failed a while ago and you didn't know it ( check engine bumb was blown) how can you be sure the pump and or valve needs replacing?

thx

[WSeffens]

i bought my e36 vert last year from a dealer that said they replaced the secondary air pump due to check light on. When i drove the car, it was fine for 1 month, then the check light came on, giving me the same codes as you report. i checked the air lines but they were fine, then read past forum messages, but most responses were like the above. i just kept resetting the codes, but worried about the coming emissions test in georgia. i discovered that if i let the engine warm up till the pump goes off, about 2-3 minutes, the check light stays off, and no codes are set. i plan on doing this again for the next emissions test. I believe it is a problem in a vacuum line near the rear of the engine, as mentioned in an old thread. Seftec

[sKunkman]

Thanks for the suggestions above, but the secondary air pump works OK and has never jammed, sqeeled or howled. I guess that gives me something to look forward to, eh ?

What actually happened was that for a long time I had a P0442 code (small evap fuel system leak) and finally had a BMW mechanic track it down. $350 later he found a crack in a hose connection on a purge tank in the rear fender well area and fixed it. When he did the P0442 code went away but it was replaced by the P1421 and P1423 codes. The link above defines P1421 as a secondary air system bank 1 problem. Anyone have an idea of what that means ? If it has to do with the secondary air pump why does it refer to bank 1 ? Also I still can't find out what the 1423 code refers to.

Kind of to bump an old thread, but I had a hell of a time searching and finding any info on this code (P0442), so I figured I would add a bit.

I had the exact same problem, the evap tank located in the rear passenger fenderwell (near the gas filler cap) is what caused the code. I took the fender liner off, took the tank out and saw no problems, so I put it back together and continued to hunt. It was only until I went to a shop and had them do a smoke test (pumped smoke through all the evap lines), and found that it indeed WAS the top left hose (nipple, on the tank actually) that had broken and needed to be replaced.

I could not see the broken nipple as the hose was on it, but the smoke test confirmed it, and when I took the hose off to replace the tank this was indeed the problem.

I replaced the tank, reset the codes, and successfully passed emissions (about 24 days past due, to be specific ).

Later I was driving (a good 3-400 miles later) and the CEL came back on. Codes P1421 and P1423. I had earlier replaced the secondary air pump (used, from a friend) and the check valve thinking it would help get rid of the CEL. Well, the codes went away for long enough to pass emissions but later came back on (I'll admit, I was driving the car bone cold, which probably triggered the CEL).

So the moral of the story is:

If you have p0442, it's most likely the evap tank in the rear passenger fender well.
If you have p1423 and p1421, replace the air pump and check valve.
If you're too broke to replace those parts, you can just let the car warm up for 2-3 minutes before driving it and you won't trigger the CEL (the pump only runs for about 2 minutes).

I think this is the longest post I've ever made, so I'll stop typing now.

[Stealthyfish]

If you have p1423 and p1421, replace the air pump and check valve.
If you're too broke to replace those parts, you can just let the car warm up for 2-3 minutes before driving it and you won't trigger the CEL (the pump only runs for about 2 minutes).

Thank you very much. I was trying to find out what P1423 and 1421 were and how I could cheapily fix it. Do I have to reset code now. My check engine light is on and comes on immediately when I start up my car.

[ejwalden]

Hey Everyone,

So, I have searched a lot and found a lot of advice similar to above. It seems though, that most people who get code P1423 get code P1421 along with it. Well, my OBDII is only throwing code P1423. The default message is "Manufacturer controlled auxiliary emissions controls". Does anyone have any suggestions on what to check when just this one code is being tripped? As far as the secondary air pump, when I start my car cold I definitely hear it come on as it makes a somewhat loud noise from the passenger side under the hood. If I can hear it, the pump is working but is it a bad sign that it is pretty loud?

As a side note, I plan on replacing the O2 sensors in the next two weeks because I'm not sure if they ever have. I have a 1998 323i vert with 113xxx miles.

[ejwalden]

Hey Everyone,

So, I have searched a lot and found a lot of advice similar to above. It seems though, that most people who get code P1423 get code P1421 along with it. Well, my OBDII is only throwing code P1423. The default message is "Manufacturer controlled auxiliary emissions controls". Does anyone have any suggestions on what to check when just this one code is being tripped? As far as the secondary air pump, when I start my car cold I definitely hear it come on as it makes a somewhat loud noise from the passenger side under the hood. If I can hear it, the pump is working but is it a bad sign that it is pretty loud?

As a side note, I plan on replacing the O2 sensors in the next two weeks because I'm not sure if they ever have. I have a 1998 323i vert with 113xxx miles.

Just as a follow up to anyone with the same situation, I replaced the pre-cat o2 sensor and the CEL light turned off. It has been a week now and it hasn't come back on. One thing to check if you are getting only code P1423.

Eric

[Irate 328]

i was driving yesterday and went to pass some one, rpms went up to around 5k in second and the car shuttered. my cel light came on. i got home and the whole car was shaking and the motor was knocking pretty hard. i turned it off and back on and it ran fine. i scanned it and got P1421 and P1423. i also had a previous code (P0135) for an o2 sensor. the car doesnt feel like it use to and when i get on it throws those codes. i havent checked the secondary air pump yet but i guess thats where ill start.