Car is still not right......05 v6.....help

[nh9095]

A few months ago I was driving my 05 v6 Cayenne and while sitting in a drive thru w/ ac on my CEL came on. Upon arriving home I checked codes w/ durametric and had the following codes:

motronic 7.1 module - code p0441

Evaporative Emission System - Incorrect purge flow/ Short to ground or Positive present

A/C module - code 353

Feedback from blower regulator front - Short to ground or positive

Electrical System - code 2197

Potentiometer for footwell lights

Cleared the codes and a few days later while car was running but in park and ac on CEL came back on. Checked codes again and had

p1009 - Oxygen Sensor Behind - Catalytic Converter exchanged

353 - Feedback from blower regulator

457 - Vehical electrical system control (kessey module)

Took it to local Indy dealer who deals w/ Porsche, Audi, VW, Mercedes, BMW etc.

They put in new rear o2 sensors and new blower regulator and new evap purge solenoid and reset codes. Left the shop and CEL returned. I pulled into an autozone and had them check my battery and it was low. I returned to Euro shop later and told them battery was low and I thought it may be causing codes. They replaced the battery and cleared codes. I then drove car for about three weeks w/ no returning codes. Then the CEL returned. I took it back to Euro shop and the owner kept the car for the day. He had it hooked up to a diagnostic and said he thought the tech had put right o2 sensor on left and left o2 sensor on the right. He said after he changed them he was getting good flow on computer diagnostics. He reset the codes and I drove the car home w/ no cel. The next morning I turned the car on and it revved higher than normal for about 5-10 secs and then returned to normal and CEL light came on. I took it to Autozone to have battery checked again and their computer said I had a power drain somewhere in the car. All of my lights are off and I see nothing on that should be causing a drain. Also noticed when I first start it in the morning after running for about 10 secs it makes a slight sputtering sound for about 20 seconds and then is fine. Any other times I start the car during the day its fine, only the first start in the morning. Today I noticed my wife had the lights on Auto but when I was behind a car in the middle of the day(bright and sunny out) my lights were on. I proceeded to turn them to the off position and leave off. Current codes are:

p1009 Oxygen sensor behind cat converter exchanged

p2096 unknow dtc 18528 present

1520 rain sensor/light sensor

Car is returning to the shop in the morning. I think it is related to the battery especially since everything cleared up for three weeks when a new one was put in. Could the auto lights have done this. Any suggestions guys. Thanks

[wvicary]

Have you ever replaced the ignition coils or spark plugs? Coil 5 & 6 often get damaged from water and cause an odd misfire when cold that only last a few seconds and sometimes doesn't set a fault code. If you have a battery drain it often manifest itself with slow cranks speed/no start conditions from being parked up over night and multiple codes for low battery conditions in many modules.

I've no idea what your tech working on the car is on about with good flow and such or the O2 sensor issue.

[nh9095]

Have you ever replaced the ignition coils or spark plugs? Coil 5 & 6 often get damaged from water and cause an odd misfire when cold that only last a few seconds and sometimes doesn't set a fault code. If you have a battery drain it often manifest itself with slow cranks speed/no start conditions from being parked up over night and multiple codes for low battery conditions in many modules.

I've no idea what your tech working on the car is on about with good flow and such or the O2 sensor issue.

wvicary, thanks for the response. You have been helpful throughout my situation. This has been a trouble free car for the three years i've owned it up until the last three months. I was wondering about the coils myself and will have them checked tommorow. I'm sure its better to go ahead and replace them all at once. The plugs were changed around April or May of this year(Bosch plugs oem spec). Should I replace them again if the coils need replacing? I think what I was trying to describe about the good flow was I believe he hooked car up to obdII or something similiar and monitored graph w/ car on. Said one was reading high and one was reading low but when he switched the o2 sensors he said that the pattern of the two were more together and flowed well.....I'm picturing a bar graph w/ two lines moving as car idles but just my thought. They actually restore old Porsche's etc and always have high end cars in(maserati etc) so I believe they have some knowledge but I don't think they have worked on very many if any Cayennes(I see some touaregs occasionally in the lot). Do you think that my sensor for my auto headlights is probably bad since it shows up on the code and since they stay on in bright daytime sun? I wonder why I still have the o2 sensor? He stated that both o2 sensors looked the same....but are obviously different since 2 different part numbers. We'll see what happens tommorow. I just want that cel to go away. Thanks for the input

[wvicary]

The ignition coils are a common problem but the spark plugs should be fine. The light sensor could very well have failed but I think you have a charging system problem that needs to be addressed. Have your garage monitor the alternator output over a 10 minute period with all of the vehicles consumers on such as head lights, A/C, emergency flashers and such. I have seen a few problem vehicles where the charging system test fine under a normal quick load test but fails when exposed to a large demand over a few minutes at idle speed.

[nh9095]

The ignition coils are a common problem but the spark plugs should be fine. The light sensor could very well have failed but I think you have a charging system problem that needs to be addressed. Have your garage monitor the alternator output over a 10 minute period with all of the vehicles consumers on such as head lights, A/C, emergency flashers and such. I have seen a few problem vehicles where the charging system test fine under a normal quick load test but fails when exposed to a large demand over a few minutes at idle speed.

So I dropped it off at the shop yesterday and they kept it for the day. Told them all of the signs that I had noticed. Upon returning they said they had been monitoring all day, had cleared codes and codes had not returned. I stated that the codes normally only return in the morning after it has sat overnight. They then asked to keep car overnight but my ride had already dropped me off. So they gave me a volt meter and told me to check my battery level in the morning and that it should be between 12.25 and 12.5. When I tested the car this morning before starting it was 12.36. I then drove the car for a morning trip and upon returning home checked the codes although no CEL had returned. Current codes are:

p0056 hO2 S Heater control circuit, Bank2 sensor2, No signal communication

p0036 hO2 S Heater control circuit, Bank1 sensor 2, No signal communication

I cleared these codes and will drive more today and recheck battery and codes in the a.m.

They want me to return car and leave it overnight. The shop is apolagetic but says they are stumped. I mentioned the coils and will make sure they do the 10minute test of the charging system on next visit. I'm so over this but hope once we get it figured out it will be back to fun driving. Thanks wvicary.