: A few codes to clear up (02 Deville)



soccer_eldorado
11-29-11, 11:57 AM
Hello,
I have 4 persistent PCM codes in my 02 Deville. First, PCM 0174, which says fuel trim lean in bank 1(I think, possibly bank 2), which I think explains random missfire after car is warm, but how do I fix that? Next, I have the pcm 1571 and 1860 which I know are related to the Torque Converter Clutch Lockup solenoid, I know that is very difficult to get to, but I rarely drive above 55, so I'm not too concerned with it (mostly Miami Freeway traffic). The next is the PCM and U1040 codes, which deal with the EBCM sending no data, I'm planning on having that sent to be rebuilt off of this rebuild company I found on ebay. What do you think causes the PCM 0174?

Ranger
11-29-11, 12:58 PM
P0174 is cause by a vacuum leak and is "usually" accompanied by P0171 on the 2000+ engines. The cause is almost always a ripped plenum duct. That's the rubber coupler between the TB and the intake manifold.

soccer_eldorado
11-29-11, 02:23 PM
HMMM, I replaced the plenum with a new dealer one about a year ago

Ranger
11-29-11, 03:53 PM
In that case you might check the PCV dirty air hose connection on the rear cam cover as well as all the vacuum lines.

Submariner409
11-29-11, 05:10 PM
In that year, with the divorced MAF, any loose clamp or torn intake duct at or after the MAF will also set mixture codes.

soccer_eldorado
11-30-11, 10:49 AM
discovered one more thing, the air line that connects to the air valve connected to the rear exhaust manifold does a funny thing. When it's connected, I get rougher idle and a "put put put" sound, almost like an old 60's cadillac, but when I disconnect that air line, the engine becomes whisper quiet, almost like its not even running. I'm guessing that valve (not sure of the name, but the one you have to remove to get to the rear coil pack) is clogged. Would I be able to clean it out, or do you think it needs replaced? ($200, not that big of a deal, but seems a little excessive). I'm getting the pcm0410 code which is for the air pump, but I can hear the air pump running on startup, maybe this clogged valve is the culprit?

Submariner409
12-01-11, 02:01 PM
The AIR diverter valve(s) inject cold fresh air into the exhaust manifold(s) at cold start to quickly light off the cat. If you're getting a putt-putt-putt noise then the piping downstream of the valve - or the valve itself - is leaking exhaust gas.