sfcacique

Drivability and OBD Codes Assistance Requested
Hello All,

I have a 2010 BMW 535iXT (N54 engine) with almost 100,000 miles. I have a couple of issues I am addressing, which triggered another set of issues possibly. Hopefully someone can show me what I may have done incorrectly while I was "fixing" my car. I do have Bentley manual, code reader and am researching OBD codes, etc but I don't have any OBD experience and minimal context.

Scenario: Two years ago I had a catastrophic failure of the electric water pump. As I was away from my home area, I had the dealership address it. They exchanged the electric water pump, but NOT the electric thermostat or the silly, PIA short hose connecting the thermostat and water pump. Car drove fine since.

Now that I am pseudo-retired, I am more engaged in doing my own maintenance. I noticed the ubiquitous oil leaks from the oil filler/oil cooler gaskets and decided to address them. "While I was there" I also wanted to address replacing the serpentine belt, tension adjuster and the two idle pulleys. I also figured I should replace all the primary coolant hoses and a new thermostat. Replacing oil filler/cooler housing gaskets involved taking off most of the air plumbing and intake manifold. Everything seems to have been put back in place correctly, and torqued down. I changed O-rings where I did not replace hoses.

I finished the radiator hoses, overflow container, serpentine belts,pulleys… etc. I bled the coolant system. Most of the car is re-assembled, minus the cowling and radiator covers and the beauty cover. Car started fine, almost immediately started a mild, intermittent misfire which increased in intensity and repetition. Car showed an orange engine with a cross bar over it and the limp mode started.

SITUATION: I am a firm believer that if something seems to go wrong with your car when you are "fixing it" then it is probably from some unexpected change you instituted. I have a brand new Foxwell NT301 scanner/reader. I have NEVER used any code reader before. Here's the readout.

$7EC - No modules reported

$7E8
P052B Cold start A Camshaft Positioning Timing over retarded bank.
P0304 Cylinder 4 misfire

I/M
Mil - shows lightbulb
DTC shows a red two with a circle around it ($7Ec and $7E8?)
Ignition shows "Spark"
pd DTC shows orange two with circle around it
Air shows a circle with diagonal red bar
EGR shows a circle with diagonal red bar
HCAT shows a circle with diagonal red bar

So,,,, anything to check out that might have caused the misfire and over-retardation? Anything I should do before I address before I start replacing coils/plugs/valve cover gasket? Why do I have a camshaft misposition? MAF / VANOS sensor(s) implications? Intake manifold not on correctly? Enquiring minds want to know. Thanks for any assistance you may be able to provide.

Dappman

Definitely don't start replacing anything. If this problem wasn't there before you worked on it you did something wrong. Are you sure you plugged in the connectors at the front of the engine between the fan and the engine? Those are related to cam timing and you would have been working around there. There's also 2 or so small bolts very near the coils that I believe are grounds, check those. Gotta recheck every connector and bolt other than that I hope you didn't put something like 0w-20 oil in it that can cause cam timing errors.

sfcacique

I just went back and rechecked everything. I ALSO replaced the intake manifold gasket(s) while I was back there (N54 engines have a "hidden" bolt for the oil cooler/filler housing back there). I had originally planned to replace it when I did the oil cooler/filler housing, but decided I had too much apart in an area I was uncertain of. As planned for phase II, I replaced the valve cover gasket, which was minimally leaking, replacing all the spark plugs and coils with BOSCH OEM.

I did recheck each vacuum line, torque, nut, bolt, squeezy toy and fitting.

Same P052B code came back, but the cylinder rmisfire did not. I had switched the #1 and #4 coils during my second phase of trouble shooting/valve cover replacement and the misfire went with it.

I did check the three ground bolts under the valve cover "near the coils". They were removed and reset as part of the valve cover gasket replacement.

I have considered the electrical on the front of the block. Two are Camshaft Position Sensors, and two are VANOS Solenoids. I also am considering the oil pressure sensor on top of the oil filler assembly. Not sure it actually moderates anything or just uses that sensor to light up the low/high oil pressure indicator in the cabin.

Because of the oil leak(s), the front of the engine block was very dirty from old oil and dirt, as was the oil filler/cooler assembly. Cleaning up the area(s) my have contaminated the connections. The oil pressure sensor also had 1" of exposed copper wire on the sensor connector wiring. I check and no obvious breaks or frays in the copper wire. I shrink-wrapped the wire. No change in codes.

I saw a YouTube video that cleared the 0015B code by removing the VANOS solenoids and cleaning them. I'm doing a quick check to see if others have done that. The VANOS solenoids and the oil pressure sensor might have gotten even more gunked up from stirred up oil sediment from places that don't seem to routinely drain when you do oil changes. I drained the oil (and coolant) as part of the procedures, but still had a old oil and sediment drain from parts.

So, this morning's checks are to remove, clean e-install oil pressure sensor, VANOS injectors and possibly replace a camshaft position sensor.