KHE

I figured out what the problem was - a bad coil on the rear bank. When the engine was cold, the car ran fine. Once the engine was up to operating temperature, the misfire would occur. Sometimes, the misfire was slight and other times, it was severe. I borrowed a friend's Actron CP 9180 scan tool but it did not have the capability to display misfire counts and all it did was display PCM P0300 which was no help... I went to the storage facility where I keep my '05 Deville for the winter and removed the front set of coils. I installed them on the front bank of the '04 and took it for a drive - it was misfiring once the engine warmed up so the front coil unit was good. I then removed the rear coils and installed the front coil unit from the '04 in the rear bank and put the '05 coil unit in the front bank. I took the car for a drive and it ran fine. When the warranty replacement arrives, it will be an easy swap on the front bank vs. fighting with that air pump solenoid unit on the rear bank.

I discovered a very loose boot that connects the PCV valve line to the intake manifold and thought I had it diagnosed. I put a zip tie at each end of the elbow and it is now snug. Took a test drive and PCM P0300 set, blinking service engine soon light. The intake coupler was replaced when I had the head gaskets done three years ago so I doubt that is the issue. When those tear, they set the PCM P0171/P0174 code and those are not set. I need to find someone with a scan tool that can monitor misfire counts in order to proceed with the diagnosis. I believe it is something simple but I don't want to fire the parts cannon at it.

It is a coil on plug system - eight coils. I have verified I have spark on all cylinders. The spark plugs and coils are OK.

I don't think it is a fuel quality issue - I don't think it was fueled up prior to the misfiring (wife's car). It is not re-setting the PCM P0300 code but I can definitely feel it misfiring. None of the parts stores in my area have the ability to read the misfire data - only the codes which I did from the dash. What brand of scan tool do you use as a Tech 2 is out of my price range. I am going to check the PCV elbow at the intake manifold and the injectors to rule them out.

The '04 Deville developed a severe misfire the other day. Blinking service engine light and PCM B0300 CURRENT misfire code was stored. I suspected it was a bad coil but all eight coils were replaced about three years ago as they failed one by one back then. I removed the coil assemblies and spark plugs - one bank at a time and tested for spark - all eight coils had spark. I noticed a fair amount of oil in the #3 or #5 plug well and cleaned it up and reassembled everything. I started the car and the PCM P0300 changed to history but I could still feel a misfire. I don't have a Tech 2 so I am not sure what cylinder is misfiring or why it is misfiring when there is spark on all cylinders. I suppose it could be a bad fuel injector - I plan to check into that in a couple of days when I get some time. I am also studying the information on the PCM P0300 code in the service manual.

It's fixed. I could not remove the lock cylinder since I could not insert the key and the lock cylinder couldn't be rotated to depress the release pin. That failure mode was not listed in the service manual... I could not find any information online other than a locksmith from Georgia who repaired the same issue on a 2001 Deville but the video did not include the method he used to remove the cylinder... I called a locksmith because I did not want to risk causing any damage to the column. The locksmith confirmed there was a bent wafer in the furthest position in. He removed the piece that has the two wings and worked it with a couple of picks and was able to remove it. He replaced the bad wafer and re-installed it and started the engine. I just need to re-assemble the covers, steering wheel, etc.

The column is locked - I can't move the shift lever out of park as the key won't go all the way in to unlock the column. The column being locked presented a problem as I couldn't rotate the steering wheel to access the airbag release clips. I was able to remove the lower column shroud and depress the lock pin with a right angle pick enough to rotate the steering wheel enough to access the airbag clips. The center airbag is out and the steering wheel is ready to be pulled. My puller is for the old style Saginaw columns that have threaded holes for the puller. This one takes the type that uses j-bolts so it's off to one of the parts stores to borrow a puller. My plan is to get the lock cylinder out tonight and get a new one ordered tomorrow morning. Even if I were to free the existing cylinder, my fear is that it would act up again at a more inconvenient location or distance from my house.

My wife was running errands yesterday and the ignition key could not be inserted into the ignition. I drove over to where the incident occurred and sure enough - the key could not be inserted into the ignition. There was a brass tab sticking down and I used a pick to get it to retract and then was able to insert the key into the ignition except for the last 1/8". I sprayed some lock graphite in there and worked the key in and out, tapping it but after 15-20 minutes, gave up and called a tow truck. It's in my garage and I am about to tear into the column. I figure the lock cylinder is worn out or somehow damaged. I figure it's going to take a new lock cylinder and have a locksmith re-key it to the existing keys.

A little lifter tick is not a big deal compared to loading the crankcase and exhaust with moisture by starting frequently during the winter months. I used to start my car up during the winter months too until the guru told me that I was doing more harm than good to the engine.

Even if I would have known the screw had left hand threads, it wouldn't budge. It was seized into the bushing of the sensor which was strange since the car doesn't see road salt. I wonder what the failure mode is on these sensor? Mine was most likely some component on the circuit board. I would bet the seizure of those screws in the sensor is the reason a new screw is included with the sensor. The new one in my car has anti-seize on the threads. Hopefully, I don't need to do the job again but if I do, it will be much easier.

My '05 Deville had the airbag light on and a SDM B0101 CURRENT code. It just happened one day a few weeks ago when I backed it out of the garage to wash it. I store it winters and have put less than 1000 miles on it this driving season. The shop manual defined the code as "front impact sensor discard". The manual concentrated on the SDM B0100 which is an opened sensor and there was not much information on the B0101 code. I figured the sensor was shot but the retail price of the sensor is $220.00 - I decided to remove the sensor from my wife's 2004 Deville and install it in the '05 to see if the code went away. The sensor is mounted on a crossmember behind the radiator - the splash shield needs to be removed to access the bolt. It wouldn't budge so I abandoned the idea - if something went wrong and the sensor got damaged, I'd be buying two of them... I decided to take the sensor out of my car and plug it into the '04 to see if the SDM B0101 code set on the '04. No luck - I broke my T-30 torx driver socket. I thought if I unplugged the sensor and the SDM B0101 changed to history and the SDM B0100 code set, there was a good chance the sensor was bad. Sure enough that is what happened. I used to order parts from Brasington Cadillac in Florida - great prices and the parts were delivered to my door in three days. They became Palm Chevrolet Cadillac and are now Davis Chevrolet Cadillac. Long story short - they don't discount parts anymore. I ordered one from gmpartsgiant.com for $159.00. It arrived Monday and I immediately noticed the screw was a left hand thread! The service manual made no mention of that! I attempted to remove the screw from the old sensor but it would not budge - even after removing the radiator support cover and spraying the exposed threads with penetrating oil. I then decided to drill out the screw using a 1/4" drill bit at a low speed to not work-harden the screw. I got just past the bottom of the torx feature and very few chips would generate. That screw was hard as rock. I didn't have a cobalt drill bit so I kept drilling, keeping the drill bit lubed with cutting oil. I got to a point where I was able to get a small cold chisel in there and gave it a whack with a ball peen hammer and the head popped off and I was able to remove the old sensor. A cobalt drill would have made the job much easier. I lubed the screw that came with the new sensor with anti-seize and installed the new sensor and no more code/airbag light. I inspected the old sensor and could not see any cracks or any evidence of water intrusion. I sawed it open and saw a small circuit board - something must've failed on the circuit board. I thought I'd post this as there was very little information on the various forums about the B0101 code and certainly no mention that the mounting screw had left hand threads. If anyone has to change out the sensor on their car, it is a left hand thread so turn it clockwise to remove it. If it won't budge, buy a 1/4" cobalt drill bit and drill the head down to the body of the screw. The cobalt drill bit will make the job much easier.

Your list is decent except for the part on running the engine once per month. One thing that should be done is to change the engine oil and filter just prior to storage so that there is fresh, clean oil on the bearings for the storage period. The WORST thing you can do to a car in storage is to start it and let it run. Coolant temperature has nothing to do with oil temperature. All you're doing is loading the crankcase with blowby and moisture. The exhaust is also being loaded with moisture. The only way to get the engine oil hot enough is to drive the car for 10+ miles (which you don't want to do with a stored car as it will get full of salt). Prep. it, park it and leave it until spring.

Mike, Same here.

Terrance, I'm not sure if it is still working - I sold the '96 SLS in the Fall of 2010. Hopefully it's still working. Further experimentation on a '97 STS showed a 4700 ohm resistor did the trick but that was an STS, not an STS and the systems are different. The '97 STS went to the junkyard in early 2017 (at 225,000 miles on the clock) due to a cracked water jacket on the engine block. My current fleet is a '05 and '04 Deville plus the '93 Fleetwood Brougham that I have owned since it had 15 miles on the odometer. The Fleetwood Brougham has always been reliable as are the Devilles - probably one of the reasons I've been absent from this discussion board for awhile.

Glad to help out. The Fleetwood Broughams are great cars - they'll never build another car like them. I'd start at the trunk tamper switch - make sure the wire is not shorted out.

The lights on the headliner are switched on and off by pushing the textured portion of the lens. The exact symptoms you are experiencing are outlined in the service manual: All courtesy lamps and roof rail lamps stay ON with ignition in RUN or 10 minutes with the key off. The information below is from the 1993 shop manual - your car might be slightly different since it is a 1995 but I think the main differences were in the engine and transmission. Check: Circuits 156, 157, 158 and 159 for a short to ground. Also check for shorted front door key tamper and rear deck lid tamper switches. Circuit 158 is the black wire from the central control module (CCM) to the headlight switch. The CCM is in the trunk behind the rear seat. Circuit 157 is the grey wire between the CCM and the mini wedge switches in each of the four doors. They control the DOOR AJAR light, illuminated entry, and the courtesy lights. Circuit 156 would be the white wire from each door key tamper switch and trunk key tamper switch to the door mini wedge switches. Circuit 159 is a grey wire from the CCM to the door mini wedge switches. An easy way to isolate the problem is to unplug one switch at a time and see if the problem goes away. Once you find the circuit that is causing the problem, you can then inspect the wires for a short to ground or substitute another switch to see if the switch is bad.

When the battery is connected, do the lights remain off or do they come back on? There could be an issue with the switch on the dash or one of the switches in each door that causes the body control module to think there is a door open. Is the "DOOR AJAR" light illuminated?

Daddy Dave didn't state what model of 2005 Cadillac he has but reading the information from the owner's manual that were recently posted, I am guessing it is not a Deville. The 2005 Deville/DHS/DTS were the last models that could display the codes on the information center. Can you post page 2-47? It looks like there are customization settings for the locks that should fit his needs.

I did the ring cleaning procedure in a '97 STS I used to have. There is no need for the Kent Moore tool. The key is to let the top engine cleaner sit in the cylinders as long as possible. It took me a couple of days - jacked up the rear of the car as high as I could to get the rear cylinders closer to level. Poured in the TEC through the spark plug holes. Let it sit for 24 hours, then lowered the rear and jacked up the front of the car, repeated the TEC injection and let it sit for another 24 hours. Once the fronts were done, I used a MityVac vacuum pump to such as much of the TEC out of the cylinders as I could. I disabled the ignition and with all eight spark plugs removed, cranked the engine until the TEC quit spewing out of the spark plug holes. Next, change the engine oil as it will have a fair amount of TEC in it that seeps past the rings. Start the engine and go for a drive. Hammer it and it will smoke like crazy for a few miles until all the TEC burns off. Then change the oil again after a couple hundred miles. That procedure seemed to reduce the oil consumption but it's been so long ago I can't really remember. The TEC is not cheap and you'll need several containers of it to do the job. The Rotella 10W-30 is a great oil for these engines. I do not miss the pre-2000 Northstars with respect to oil consumption. I have a 2004 Deville and a 2005 Deville and it is very rare to have to add any oil between oil changes.

Yes - I had an extensive phone conversation with the guru when I repaired my Seville STS engine several years ago. The head bolts are not torque to yield. They provide constant clamping force due to the low static torque and the angular specification which removes friction from the equation as compared to just a standard torque value. Torque to yield bolts do get into the plastic region - that is the design of the rod cap bolts.

Probably wrong terminology - the head bolts do not get into the plastic/elastic region. If there was a practical method to clean and re-apply the micro-encapsulated threadlocker, the head bolts could be re-used over and over. The rod bolts are torque to yield bolts - there is no threadlocker on them and the shop manual states they are not to be re-used.

The Northstar head bolts are not torque to yield bolts. They have a microencapsulated threadlocker that acts as an anti-seize and locks them into place. There is no practical way of applying it in the field and there is not a substitute, so the procedure is to replace the head bolts. Glad to help. If you go to Timesert's website and look up the manufacturer's specific kits, in the Bigsert kit description, it actually says "for use when a Heilicoil pulls out" or something to that effect.

DO NOT use Heilicoils in the Northstar engine - you will rip them out of the block the minute you torque the head bolts. Then you will need to use a Bigsert (large Timesert threaded bushing to repair the block). I tend to think that using Bigserts may weaken the block. I had a block crack on my '97 Seville after several years of service (that I repaired with Bigserts). I realize it is only one data point but I have no idea why other than it weakened the block enough that the internal stresses eventually caused the block to crack.

AC Delco.

Unless you have some service documentation that indicates the headgaskets were replaced, there isn't an easy way to know unless there are aluminum shavings on the block somewhere. My guess is that with only 93,000 miles, it most likely has not been Timeserted. Keep the coolant changed on a regular basis and drive it.