244C00 Fault Code: Charge Pressure Control, High Pressure Stage Deviation (BMW Diesel)
244C00 is stored by the DDE on BMW diesels and means the high pressure stage turbo cannot reach the requested charge pressure. Typical causes are the VNT actuator, a vacuum leak or soot buildup.
— Tekin Code
244C00 is written in BMW's newer six-digit fault code format and is stored by the DDE (the diesel engine control unit). It means "charge pressure control, high pressure stage — control deviation", which in practice means charge pressure stayed below target. You will see it on diesel engines such as N47, N57, B47 and B57, particularly with two-stage turbo systems. Severity is moderate to high: the car usually shows a "Drivetrain" warning and limits power, and if ignored it also disrupts DPF regeneration.
What Does 244C00 Mean?
In six-digit codes the first four digits identify the fault location and the last two the fault type: 244C is the high pressure stage of charge pressure control, and 00 means control deviation — drifting away from the target. In two-stage turbo systems the small (high pressure) turbo is the one that provides response at low RPM and low load, and 244C00 says precisely that this region is missing its target.
That is why the code usually appears when pulling away, at low RPM, and the moment load is applied; it may never show up at a steady motorway cruise. If other drivetrain codes such as 27F100 or EGR/DPF codes sit alongside it, they help narrow the diagnosis.
Code .............. 244C00
Definition ........ Charge pressure control, high pressure stage - control deviation
(charge pressure too low / positive deviation)
Module ............ DDE (Diesel Engine Control Unit)
Format ............ 244C = fault location, 00 = fault type
Severity .......... Moderate to high - power limitation, DPF regeneration at risk
Common engines .... N47, N57, B47, B57 (F and G series diesels)
Symptoms
• "Drivetrain" warning in the instrument cluster along with the Check Engine light.
• Clear power loss at low RPM; the car feels as if it only wakes up higher up.
• Poor response when pulling away and on inclines, followed by limp mode.
• Black smoke from the exhaust, especially under load.
• Higher fuel consumption.
• DPF regeneration failing to complete, with soot load warnings increasing over time.
• The problem temporarily disappearing after switching the engine off and on.
Possible Causes
• Loose or misadjusted turbo actuator rod/clip — a known issue on BMW diesels and one of the most frequent causes.
• VNT/VTG vanes coated in soot and sticking; the vanes cannot move whether the actuator commands them or not.
• On vacuum-operated systems: a disconnected or cracked vacuum hose, a failing vacuum pump, a leaking vacuum reservoir.
• On systems with an electric actuator: a failed actuator motor or a drifted position signal.
• Charge air leak — intercooler hose, clamp or a cracked pipe.
• Contaminated or drifted charge pressure sensor.
• A blocked DPF or excessive exhaust back pressure preventing the turbo from reaching target.
• An EGR valve stuck open or a leaking EGR cooler.
• Clogged air filter or a crushed intake duct.
• Mechanical turbocharger failure — bearing play, wheel damage (the most expensive scenario).
Diagnostic Steps with OBDThink
The goal with 244C00 is to find the operating point where the deviation appears. Does it only show up at low RPM, or is boost short everywhere? That distinction separates an actuator problem from a leak.
• 1. Scan all modules. Note any EGR, DPF or other drivetrain codes next to 244C00 — on diesels these systems trigger each other.
• 2. Read the freeze frame: at what RPM, load and coolant temperature was the code stored? Low RPM plus high load is the classic 244C00 scenario.
• 3. Watch target and actual charge pressure together in live data. A gap that opens at low RPM shows the high pressure stage is not engaging.
• 4. Watch actuator position/duty: if the DDE commands movement and position does not change, you have mechanical sticking or a detached rod.
• 5. On vacuum systems, measure the vacuum reaching the actuator; if it is insufficient, check the pump and lines first.
• 6. Inspect the actuator rod by eye and by hand with the engine off: is the clip in place, does the rod move freely, is there play?
• 7. Evaluate DPF soot load and exhaust back pressure; with a restriction the turbo will never reach target.
• 8. Pressure- or smoke-test the charge air system for leaks.
Reference values (vary by engine and calibration)
Ignition on, engine off:
Charge pressure sensor ... ~1.00 bar (equal to ambient)
Idle:
Charge pressure .......... ~1.0 - 1.2 bar absolute
Actuator position ........ must follow the command
Under load (2000 RPM, full throttle):
Boost target ............. 1.8 - 2.4 bar absolute
Boost actual ............. deviation should stay < 0.2 bar
EXAMPLE OF A FAULT:
At 1500-2500 RPM target 2.1 bar / actual 1.4 bar -> high pressure stage not engaging
Actuator command 70%, position frozen -> rod/clip detached or vanes stuck
DPF soot load at critical level -> fix the exhaust side first
Record a short load test between 1500 and 2500 RPM with OBDThink. That is where the deviation is clearest with 244C00 — at a steady motorway cruise you may see nothing at all.
The Fix
• Actuator rod and clip: refit a loose clip and set rod adjustment to the manufacturer's spec. Low cost and, surprisingly often, all that is needed.
• Vacuum hoses and vacuum pump: renew cracked lines, replace the pump if its output is low. Low to moderate cost.
• Turbo actuator (vacuum or electric): replace if it does not respond to commands; electric actuators need adaptation after replacement. Moderate to high cost.
• VNT vane cleaning: the turbo must come off to be cleaned when soot has built up. Moderate to high cost.
• Charge air system: repair cracked pipes, split hoses and loose clamps. Low cost.
• Charge pressure sensor: replace if it deviates from ambient. Low cost.
• DPF: forced regeneration when soot load is high, cleaning or replacement if the blockage is permanent. Moderate to high cost.
• EGR valve/cooler: clean or replace if it is leaking or stuck. Moderate cost.
• Turbocharger: overhaul or replace once shaft play or wheel damage is confirmed. High cost.
Do not skip the adaptation/learning procedure after replacing an actuator. Fitted but uncalibrated, a new actuator will bring 244C00 back within a few miles.
Can You Still Drive With This Code?
A short, careful drive to the workshop is acceptable, but there are two real risks: sudden power loss in limp mode is dangerous in traffic, and low boost blocks DPF regeneration, pushing soot load towards critical. If regeneration cannot complete, a small actuator problem turns into a far more expensive DPF repair. Avoid long trips and heavy loads.
Clearing 244C00 brings temporary relief, but the fault returns on the first loaded pull-away. The right order is: fix the mechanical cause (rod, vacuum, vanes, leak), clear the fault memory with OBDThink, then watch target/actual boost and actuator position again during a short load test between 1500 and 2500 RPM. If the deviation stays under 0.2 bar and the code stays away over several drive cycles, the repair worked.