Welcome to Tech Talk, where our resident BMW tech Nick Owen answers all your pressing BMW technical questions, frustrations, and issues. Have a question for Nick? Email him at techtalk@roundel.org. Let’s get into it.
TRANSFER ME OVER
I have a 2011 F25 X3 2.8i with ~125,000 miles; it is my son’s college car, and now that he’s graduated, it’s about to become my daughter’s Brooklyn car.
Last summer, the boy came home from college and said that there was a shuddering while turning at low speeds. The local shop said that it needed a new transfer case.
Internet sleuthing suggested a fluid change and re-flash might solve the problem. The shop did it, the problem went away, and all was good—until it wasn’t. My son recently informed me that the shudder is back. Would another fluid change “solve” it for another year? If not, is there anything short of replacing the transfer case to do?
What happens if I ignore it? Any advice appreciated.
Joshua Weinstein
The bad news is that the shudder is not going to go away; it might actually get worse. Changing the fluid and resetting the VTG motor (VTG = Transfer Case Module) might make it go away, but it will return. One very important key thing here is that the X3 all-wheel drive system is very, very sensitive to the tire size indicated on the B-pillar of the car; the wheels and tires on the vehicle must be the exact size listed on the label, because the xDrive system is calibrated only for that size, and altering it will prematurely wear out the transfer case. The vehicle basically detects a difference in wheel speed based on the different tire sizes and actives the AWD system incorrectly.
You won’t be able to feel it until the shuttering starts again. Installing the appropriate tire size might make it go away, but sometimes in that scenario the transfer case is already compromised.
If you were to ignore this issue, it could get worse—perhaps to the point where the xDrive system is no longer doing xDrive things. I have personally never seen a transfer case fail to the point where the car was undrivable, but that is just me.
LET’S BREAK IT DOWN
I have a 2008 BMW X3 with 164,000 miles on the clock. It’s running well. The X3 is being maintained by a shop that specializes in servicing German cars: BMW, Mercedes, Porsche, and the like.
Could you share with me the repairs that are associated with the following codes:
- P1775: Lack of communications between the transmission control module and the engine computer module.
- 2A17: Diagnostic Module Tank Leakage: ensures fuel tank doesn’t leak.
- 2C7F: Oxygen censor code.
- 2A38: Valvetronic monitoring of sluggish movement.
- 214F: Cylinder #3 misfiring
These fault codes have not been building over time; I got all of them at one time. The X3 appeared to be running fine. Is it possible that P1775 is the primary problem, that this fault code triggered the others? If I have to make individual repairs, this could be an expensive proposition!
According to my mechanic, these codes are representative of repair items for the X3. However, the mechanic is not able to determine what repairs need to be completed based on the codes. My mechanic suggested that I take the X3 to the local BMW dealership. I would prefer to have my mechanic complete the work; dealership repairs tend to be more expensive.
This is important because unless these repairs are completed, I will be unable to re-register my X3. Any help you can provide would be greatly appreciated!
Bruce Jackman
I am more than happy to assist, have your mechanic do the following:
- Smoke test the intake to check for vacuum leaks. This is important in ensuring there are no lean mixtures.
- If the O2 sensor fault is for sluggish movement or heater circuit, replace it.
- Replace the Valvetronic motor and sensor for fault 2A38 (the sensor might be optional, but it could contribute to improper Valvetronic signals).
- Use smoke machine to test EVAP system for fuel-vapor leaks for fault 2A17; if no leak found, replace DMTL pump.
- If misfire fault does not come back, great! Otherwise with faults 2A38 and 2C7F being rectified, you might be looking at new spark plugs and/or ignition coils.
- Is fault P1775 currently present? If so, does the car run? That fault indicates the CAN system between the EGS and DME is down, so the car wouldn’t run—or barely run.
I hope this helps point you and your mechanic in a direction. Let me know if I can be of any more use.
HELPING MAKE HAPPY DECISIONS
I am a long-time BMW owner and member of the club; my stable currently houses a ’71 2002 ti project, a ’72 Bavaria, a 1976 2002, a ’95 M3, an ’04 330i ZHP, a 2008 328xi, a 2017 X3, and a 2018 M2—so yeah, I have a problem….
I am looking at buying an ’08 135i with M Sport package, manual. At 120,000 km, it’s a two-owner car with good service records and long-time owners. The car is in really nice shape, very clean, never winter-driven. I have heard all the issues with the N54 engine: turbos, oil leaks, HPFP, carbon problems. The water pump and thermostat have been serviced, brakes were done recently, it was walnut-blasted twice, the A/C evaporator replaced. I am seeking your opinion on the car as a technician: Should the known issues scare me away? There are currently no turbo rattles, no check lights, and no oil leaks, and the price is reasonable. Let me know your thoughts and opinions.
The next question: My ’04 330i ZHP has developed a strange issue. The car is well kept, with 285,000 kms. When the car is cold, it starts and runs perfectly; once hot, if I shut it off, then go to start it, the temperature gauge will peg red, and the car will fire, run for a second, and then die. Once it’s cooled down for 15–20 minutes, it starts and runs normally.
I have checked all major electrical connections, grounds, fuses, etc, swapped out the battery, replaced MAF, idle-control valve, and crank sensor. The fuel pump was replaced 8,000 km ago with a new VDO pump and new relay—aftermarket, not BMW. I also had the DME repaired, but it didn’t solve the problem, so I purchased a good used unit and replaced it, which solved the problem for three days before it returned. I am leaning toward a wiring issue, but I am stumped.
Kris Procyk
Windsor, Otario
That is a pretty good-looking stable you have there! I think that the ’08 135i is a solid buy, even with the N54. The good news about the N54 is that the problem items are limited, and there’s a solution for every one of those items. I think the anxiety of them failing on you has dropped, since we know it could happen but we know that it can be fixed. I think the N54 is a good engine, and I wouldn’t be scared of it—it sounds like you’re onto a good one. Just be aware that the items that have not yet failed could fail down the road. But once those items are rectified, the car and engine tend to be pretty solid.
As for the ZHP, it seems to me you have a hot-start problem that’s electric-related. Your temp gauge should not go into the red unless you’re actively overheating with a running engine. Have we tried swapping in new coolant temp sensors? Sometimes a shorted sensor can tell the DME to do weird things, and since the car works once it cools, it points me to something temperature-related. Faults only get thrown/stored when certain criteria are met; sometimes components on a vehicle will fail or start to fail in a manner that does NOT throw/store a fault—but will cause a symptom such as you have described. I see there are some faults stored in the pictures you provided. The faults I see are for:
- Oil level sensor
- Oxygen Sensor
- Mixture Preparation
First, replace the oxygen sensor, because the fault stored is for the heater circuit. Basically, this means that the sensor cannot get up to temperature fast enough and has become inefficient. That particular oxygen sensor is for post-catalytic converter monitoring, but the DME will still use its signal to alter fuel trim. You’re good to replace it without much more diagnosis.
Mixture Preparation means that there is a vacuum leak or low fuel delivery in the engine. On the M54 engine, nine times out of ten it’s a vacuum leak, and either the intake boot is torn or the oil separator has failed. The worse the issue gets, the worse the drivability will become, and MPG will suffer. The car might even develop a misfire or hesitation issue. I strongly recommend having this issue diagnosed and rectified.
Finally, the oil-level sensor fault got me thinking: There might have been a time long ago where a failing oil-level sensor caused a no-start issue. It’s quite possible that this is influencing the crank/no-start issue when hot. I cannot recall the exact theory on it, but you may want to look into having it replaced.
