: "Reduced Engine Power" mode and multiple codes...Help?



aaldape
03-02-12, 09:01 PM
Well, I've broken down and I'm deferring to the LS6 gurus for some help. Here's a brief synopsis of what's going on with the V, and hopefully it's enough to conjure up a few possible solutions before I'm forced to tow it to a shop somewhere...

Vehicle: 2005 CTS-V w/ 97k miles
Engine: Stock w/ K&N filter, new NGK TR5IX plugs, new Magnecor 8.5mm wires

Problem: Had what I thought was an issue with motor mounts (motor felt like it was dieseling when ignition is shut off, and online/forum searches strongly suggested motor mounts as the culprit). Then, one day on the highway, CEL comes on, and the engine runs like absolute sh!t. It felt like a horrible misfire, and the vehicle wouldn't idle long before it would stall (engine was running VERY rough and poorly, but I did not hear and noise, banging/clanking).

Opened the hood, saw that the intake tube from the air filter had come off of the motor at the intake (makes sense since I had just pulled it to clean my K&N and must not have tightened it enough when I reinstalled it). I put it back on, tried resetting the computer (pulling the fuse in the engine bay, then resorted to disconnecting the battery when that didn't work).

The engine still ran like crap, so the first code was for the MAF sensor, which I replaced, and still had the same rough idle (so I took the sensor back and reinstalled the original).

Fast forward 10 weeks later to today (was out of town for work), and I am back at it. Charged the battery, installed the plugs and plug wires mentioned at the top (LStech forums suggested misfire codes could be the result of bad plugs and wires). With a freshly charged battery and new plugs/wires, I started the engine with with fingers crossed and get the "REDUCED ENGINE POWER" mode on the Nav display.

So I'm out of ideas (I don't claim to be a mechanic, but I have always worked on my older vehicles, dirt bikes, etc), and am looking for ideas on how to fix my poor car before I break the bank for a REAL mechanic... Any help would be HUGELY appreciated!

(Oh, and Hi, my name is Alan, and I'm a long time listener, first time caller)... :D

Codes after new wires and plugs:

P0068 - MAF/MAP Sensor throttle position correlation
P0102 - MAF or VAF A circuit low input
P0300 - Random/Multiple cylinder misfire detected (original had just this code at one point, which is what made me change plugs/wires)
P0352 - Ignition Coil B Primary/Secondary Circuit Malfunction
P0354 - Ignition Coil D Primary/Secondary Circuit Malfunction
P0356 - Ignition Coil F Primary/Secondary Circuit Malfunction
P0358 - Ignition Coil H Primary/Secondary Circuit Malfunction
P0803 "Pending" - 1-4 Upshift Solenoid Circuit Malfunction

My guess on the 4 codes mentioning the ignition coil is that there is an entire bank of coils that are bad, or the source circuit is bad, or something, since it is every other Coil (a B c D e F g H...)

And the pending code? No clue, other then it has something to do with the fact that the previous owner disabled the shift interlock from 1-4 gear...

darkman
03-02-12, 09:33 PM
See attached.


The common denominator for the MAF related codes and the ignition coil related codes seems to be the Igniton 1 voltage circuit, which includes one 15 AMP fuse). Also, anytime multiple codes appear suddenly the first step is to make sure there is a known good battery in place. This means not only fully charged, but also free of internals shorts/faults.

fazz1225
03-02-12, 10:02 PM
Just food for thought, I had similar symptoms a while back with no codes though that turned out to be a bad ground...

darkman
03-02-12, 10:13 PM
Just food for thought, I had similar symptoms a while back with no codes though that turned out to be a bad ground...

Which ground fixed it?

The Ignition 1 voltage circuit uses Ground 0142, which is one of the grounds located on the passenger side cylinder head, but sometimes the "problem ground" is used for reference and can be part of a seemingly unrelated circuit.

RADEoN
03-03-12, 10:32 AM
I had the same issue, there's a harness right beside the drivers side exhaust manifold, and it came loose and fell into my exhaust manifold.

aaldape
03-03-12, 04:37 PM
Wow thanks for the quick replies all. I double checked my connectors on the driver's side fender there and didn't see an issue with the connection. So since the battery is suspect I'll start there and rerun the codes, and then go from there.

I didn't see any issues with grounds but I'll double check. I think those schematics will be the key, thanks a ton darkman.

darkman
03-03-12, 04:54 PM
I didn't see any issues with grounds but I'll double check.

The problem with the three grounds located on the back of the two cylinder heads is not really visible. The metal simply oxidizes over time and becomes insulated. The fix is simply to take them loose and hit them with a file, sandpaper, or anything that will shine them up - star washers can also so help. There is another ground underneath the post that holds up the hood. The fix on includes taking off the paint that is underneath.

CancerJCC
03-05-12, 09:38 AM
The problem with the three grounds located on the back of the two cylinder heads is not really visible. The metal simply oxidizes over time and becomes insulated. The fix is simply to take them loose and hit them with a file, sandpaper, or anything that will shine them up - star washers can also so help. There is another ground underneath the post that holds up the hood. The fix on includes taking off the paint that is underneath.

And here is the oil thread for the OP with all of them pictured:

http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-general/150519-damn-high-oil-temp-alarms-here-7.html

aaldape
03-05-12, 03:21 PM
You guys have any tips for getting to those grounds behind the cylinder heads? I thought the spark plugs were a PITA to repair, but jesus, these grounds are just as bad. Checked the ground under the hood support and cleaned/filed it, so it should be good to go. I did find that I had not connected the connector that plugs into the passenger side coil bank, so that would explain those codes (whoops). I'll go rent another code reader today and see if some of the codes cleared up after plugging in that connector.

I really hope it's one of these grounds that fixes the issue...

darkman
03-05-12, 03:41 PM
If I recall correctly the grounds on the cylinder heads take a 15mm wrench, preferrably a closed-end or gear wrench. Since the heads are interchangeable the pre-drilled holes are in same location as those on the front of the heads which will give you some idea where they are. It is best to check them with the engine cold because you need to locate them with you hands & fingers rather than your eyes.

kjr6306
03-05-12, 04:14 PM
I would just diconnenct the battery for a bit and see if that clears all your codes. The only one that may still remain is the 1-4 shift malfunction which is no big deal....

aaldape
03-14-12, 11:49 PM
Well a quick update without much progress... D/C'd the battery, took it in, and it tested fine. It's all charged up, plugged it back in, and the car is back running like it was before I pulled it. Checked codes again, this time only two codes...

P0068 (MAF/MAP sensor throttle position correlation) --> This seemed to happen after I unplugged the MAF sensor and restarted the engine just to see if it would run any differently than it was (to no avail)

P0102 (MAF or VAF A Circuit low input) --> This points me back to a possible ground issue like had originally been suggested. Any other thoughts where this would arise from?

I appreciate the input from everyone. From some resent searches online, to me, it appears obviously electrical, and it could be the TPS, MAF Sensor, or anything in those circuits that could F up and cause the "Low voltage" or whatever is happening in the "A Circuit"...

Like I mentioned in the first post, the MAF sensor was switched out for a new sensor at one point with no success, so I am running the original MAF sensor under the presumption that it is operating fine, since installing a new one did not affect the way the vehicle ran. Is the TPS sensor the next thing I should try? Or go back to the Ground connections again? Definitely looking to me like I am not cut out for troubleshooting anything newer than a vehicle from 1990...

darkman
03-15-12, 12:02 AM
See attached.

aaldape
03-15-12, 12:12 AM
Gracias senor, in my fervor to fix this I forgot I had pulled those codes earlier, good call! Thanks Darkman

aaldape
04-25-12, 10:58 PM
I never updated this, wanted to let you all know the issue has been resolved, and it ended up being a broken valve spring...

CancerJCC
04-26-12, 02:48 PM
I never updated this, wanted to let you all know the issue has been resolved, and it ended up being a broken valve spring...

Thanks for the update and glad you got it figured out. These new cars with all of their fancy schmancy electronics still have mechanical internals that can and do break! Not knocking you it is something we all seem to forget time to time.

aaldape
05-21-12, 07:13 PM
Yea, troubleshooting on my old bronco was a different sort of process. Now that I am trying to use the OBD tools to do the same job I get so caught up in the sensors and electronics that I forget that their job is to detect the mechanical problem in some way... Anyway, thanks all for the help. The V is running like a champ now with the repair and a set of new high-flow cats.