BMW Limit Flags & States
Cylinder Fill Limit Reason
As found on Cylinder Fill Limit Reason monitor for B58g2/supra and S58 (not avalable on N55/S55/B58g1
| Value | Reason | Notes |
|---|---|---|
| 0 | Standard Limitation | Cylinder Fill Desired is calculated from the current Torque Request and is not otherwise limited |
| 1 | Condensate Protection | Avoidance of high flow at low temperature to prevent condensation in the intake, not normally a problem |
| 2 | ATL Component Protection | Caused by compressor pressure ratio being limited, check your Boost Pressure Target to calculate the PR (pressure in bar will be very close to PR at sea level), alternatively log Compressor Pressure Ratio Target to asses the actual pressure ratio used. Check Turbo Pressure Ratio Limit 2d (and 3d) maps to ensure your required pressure ratio is possible. Remember this is a ratio not an offset to altitude effects combine with intake pressure loss can turn moderate boost pressures into high pressure ratios. |
| 3 | High Pressure Fuel Pump Control Limit | Limit of the High pressure fuel system is being reached. If MSV active angle reaches 126° then the pump is maxed out and there isnt much that can be done to avoid this. Lowering target fuel pressure and running less load/boost at low rpm (where the pump is typically stressed more) are worth considering. This can also occur with if the fuel flow exceeds what the ECU believes the pump is capable of, even if the max pump angle hasn't been reached. Or if the fuel pressure is sufficiently far below target.
|
| 4 | Electric Fuel Pump capacity | (Electric Fuel pump, In-Tank Lift Pump) overall fuel demand and over temp status from fuel volume. Raise EFP Load limit Maximum to increase the point where the limit is ramped down from, raise EFP Load Limit Minimum to stop the limit ramping down so far, and decrease EFP Load Limit Reduction Max Rate to slow how fast the ramping down of the limit. |
| 5 | Intake Temp, Knock and Driving behaviour Retard | Typically when the load limits in Load Limit - Ignition Retard Normal or Load Limit - Ignition Retard Sport maps are employed. Check the X axis input by looking at Ignition Retard Total logging parameter |
| 6 | Turbo EGT Component Protection Controller | Turbine Exhaust Gas Temp limits are too high. If running into this at high rpm and power but not boost check EGT Target Temperature - Turbo and raise as required, the estimated EGT can be verified by logging Exhaust Gas Temperature. |
| 7 | Particulate Filter | |
| 8 | Injection duration out of the window to inject enough fuel | Typically seen on high ethanol content and high rpm where injection window is limited. Reducing the latest end of injection using IP1 EOI (And Latest EOI for SOI based Pulse) map to delay end of injection limit from 130ºBTDC to closer to 60ºBTDC at high load and rpm. This can also be triggered if the volumetric fuel flow from the injectors exceeds the estimated flow from the pump, or if the pump max duration is reached, or if the pulses between multiple injections are too short. |
Torque Limit State
As seen on Torque Limitation State monitor, applicable to all BMW
| Bit Position | Dec. | Hex | Description |
|---|---|---|---|
| 0 | 1 | 1 | ASR Limitation through Anti-Slip Control (Torque Reduction |
| 1 | 2 | 2 | MSR Limitation by engine drag control (Torque Increase) |
| 2 | 4 | 4 | GS_DEC Transmission intervention to derease torque (typically seen on upshift) |
| 3 | 8 | 8 | GS_INC Transmission Intervention to increase torque (typically seen on downshift or speed matching) |
| 4 | 16 | 10 | NREG_DEC Speed Control |
| 5 | 32 | 20 | NREG_INC Speed Control |
| 6 | 64 | 40 | DCC_INC Longitudinal Dynamics management (Cruise Control etc.) |
| 7 | 128 | 80 | SELFSTABAB operating losses |
| 8 | 256 | 100 | Fuel Temperature Limit |
| 9 | 512 | 200 | COOLING Limitation in cooling |
| 10 | 1024 | 400 | VAR_UL Limit UL Variant |
| 11 | 2048 | 800 | NMAX Rev limit torque reduction. |
| 12 | 4096 | 1000 | VMAX torque limitation to realise a vehicle speed limit |
| 13 | 8192 | 2000 | ACC_CTL Acceleration control, typically employed when acceleratino exceeds what is theoretically possible for the current crank torque request, or overall wheel torque limits. |
| 14 | 16384 | 4000 | PARKING BRAKE Parking brake |
| 15 | 32768 | 8000 | HA_DIF rear axle gear protection |
| 16 | 65536 | 10000 | EMERGENCY RUNNING MANAGER Limitation by emergency running manager, ECU goes into limp home mode. |
| 17 | 131072 | 20000 | MD_RF Limitation by filling limitation RF torque limit calculated from a cylinder fill limit. This can occur when the cylinder fill limit is being reached, and the ECU takes action. This avoids an imbalance between torque and load requests. |
| 18 | 262144 | 40000 | MD_MOTOR Limitation by motor protection |
| 19 | 524288 | 80000 | SLAVE_STG limitation of 2nd control unit |
| 20 | 1048576 | 100000 | GS_PERM torque limit sent from transmission over CAN |
| 21 | 2097152 | 200000 | MD_RAD Breaking load drive axle |
| 22 | 4194304 | 400000 | GS_AUTARK self-sufficient gearbox protection |
| 23 | 8388608 | 800000 | KUPPLUNGSSHUTZ_HS Clutch slip protection on manual transmission |
| 24 | 16777216 | 100000 | BEGRENZUNG_GHAS controlled rear axle lock |