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Old 05-17-2011, 11:07 PM   #1
holabr
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Join Date: Oct 2004
Location: Pittsburgh
Posts: 21
My Ride: 2001 325xi
From SES to Transmission Light

The problem started out with an SES light and codes that would not pass state emissions tests. According to the mechanic, they indicated an O2 sensor which I had replaced. The codes were cleared but within a few miles of driving, the SES was back on. I had the codes read at Autozone, since I didn't want to pay the garage again. This time the code pointed to the MAF sensor. I took it off the car and cleaned it. After driving for a while, the SES light went out and I passed emissions. I thought I was home free but...

I was wrong. The SES light came back on so I assumed it was the MAF sensor and I replaced it. I also bought my own OBD II cable and software for my laptop. When I read the codes (which I didn't record) I remember them indicating lean fuel and low fuel (I did run very low on gas but never really ran out of gas). A mechanic friend, who doesn't work on BMWs, suggested that since I changed the MAF sensor, I should clear the codes and run the car to get a clear indication of what problems might still exist.

From there things started to get worse. I now had the following codes :

P1345 Misfire Cylinder 2 With Fuel Cut-off
P0313 Misfire detected - low fuel level

And the engine would run real rough.

Based on something I read here, I disconnected the MAF sensor and cleared the codes. Now the only code I get is:

P0102 Mass air flow voltage low

And the SES light is off, however now the Electronic transmission control module indicator lamp is on. Do you think these are related or have I developed a totally new problem? My OBD II software won't read the transmission codes so I really don't know what the light is telling me.

What do you suggest I do next?
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Old 05-17-2011, 11:34 PM   #2
cvx5832
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What brand MAF did you replace the old one with?
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Old 05-18-2011, 10:03 AM   #3
holabr
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I'm not sure what brand it was. I bought it through ebay as suggested by someone else on this forum.
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Old 05-18-2011, 10:13 AM   #4
g6
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Quote:
Originally Posted by holabr View Post
The problem started out with an SES light and codes that would not pass state emissions tests. According to the mechanic, they indicated an O2 sensor which I had replaced. The codes were cleared but within a few miles of driving, the SES was back on. I had the codes read at Autozone, since I didn't want to pay the garage again. This time the code pointed to the MAF sensor. I took it off the car and cleaned it. After driving for a while, the SES light went out and I passed emissions. I thought I was home free but...

I was wrong. The SES light came back on so I assumed it was the MAF sensor and I replaced it. I also bought my own OBD II cable and software for my laptop. When I read the codes (which I didn't record) I remember them indicating lean fuel and low fuel (I did run very low on gas but never really ran out of gas). A mechanic friend, who doesn't work on BMWs, suggested that since I changed the MAF sensor, I should clear the codes and run the car to get a clear indication of what problems might still exist.

From there things started to get worse. I now had the following codes :

P1345 Misfire Cylinder 2 With Fuel Cut-off
P0313 Misfire detected - low fuel level

And the engine would run real rough.

Based on something I read here, I disconnected the MAF sensor and cleared the codes. Now the only code I get is:

P0102 Mass air flow voltage low

And the SES light is off, however now the Electronic transmission control module indicator lamp is on. Do you think these are related or have I developed a totally new problem? My OBD II software won't read the transmission codes so I really don't know what the light is telling me.

What do you suggest I do next?
Holabr, it is hard to tell with the generic codes but from my own experience, everything you have posted is pointing to a lean condition. (Vacuum leak) When i had lean codes and misfires, i had the exact same course of action and details as you, almost down to the tee, even unplugging the maf and getting no other codes than the maf then. mine was a vacuum leak. i would start there because it is cheap and easy to diagnose. i am def putting my bets on a leaky valve cover gasket or the rest of the vac. system.
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Old 05-18-2011, 10:18 AM   #5
holabr
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G6, Where did you finally find your leak and how did you find it? Also, did your transmission warning light come on?

Last edited by holabr; 05-18-2011 at 03:30 PM.
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Old 07-01-2011, 05:26 PM   #6
holabr
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Ok, I seem to be making some progress. The lower air intake boot did have a rip in it. I replaced that which was quite a job since the clamp screws were facing down and toward the firewall. When I started it up the SES light went out and the only code was the MAF low voltage code remaining from before the boot replacement. I cleared that code and everything seemed fine. Now I got everything hooked up including the MAF sensor but after about 10 miles of driving I got a P1345 Misfire Cylinder 2 With Fuel Cut-off code. Do you think I still have a vacuum leak somewhere? What's the testing procedure for a DISA or valve cover gasket leak? Should I disconnect the MAF and run it for a while? Any suggestions welcome.
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Old 07-01-2011, 07:20 PM   #7
LivesNearCostco
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I'm not well versed on EFI or code P1345, but if you have eliminated possible vacuum leaks, you might look at fuel and spark, especially for cylinder 2. Possible cause might include fouled spark plug, failed coil, clogged fuel injector on that cylinder, or the fuel filter (which should affect all cylinders). But before you start pulling out any of these parts, let me ask you... your car is a 2001. How many miles on it and when did you last replace the spark plugs and fuel filter? I think the normal recommended replacement is fuel filter at Inspection II (or 60,000 miles) and spark plugs every 100,000 miles.

There are other places you could get a vacuum leak (DISA, upper intake boot, CCV, valve cover gasket) but you fixed the most common one already--the lower intake boot. Plus if you still had a vacuum leak I would think you'd get some other kind of codes too (like P0174).

Is the engine running smoothly now? Maybe find out if that "fuel cutoff code" you got means the cylinder is not getting enough fuel, the DME is cutting off fuel to that cylinder because it detects a misfire, or something else.

Last edited by LivesNearCostco; 07-01-2011 at 07:22 PM.
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Old 08-07-2011, 06:15 PM   #8
holabr
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Ok, I finally got back to working on this problem. I checked for additional vacuum leaks using the propane gas method and found nothing. My next step was to check coil pack, spark plug and injector for cylinder #2. Since the plug and coil pack were easier than the injector, I started there. I first switched the plug and coil packs between cylinder #2 and #3. I reset the code and drove the car. Now I got a P1347 which indicated the problem now moved to cylinder #3. Again I cleared the code and switched the coil packs only and the problem moved back to cylinder #2 with the P1345 code which indicates to me that the coil pack is bad. I am now looking for a replacement coil pack. Any recommendations on the brand to buy and where to buy it? I really don't want to go the the BMW dealer if I can get the same product someplace else without the BMW markup. Does anyone think that it may not be a bad coil pack?
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