Self Diagnosis - Theory & Operation (N62)

• Diagnostic Trouble Codes Index
• Catalyst monitoring
  • Notes
  • System overview and catalyst diagnosis structure
  • Catalyst check
  • In-use monitoring performance ratio (lUMPR)
• Heated Catalyst Monitoring
• Misfire Detection
  • Notes
  • Segment time formation (% )
  • Correction of the Segment Time ts(n) (%DMDFOF, see )
  • Calculation of the engine roughness values luts, fluts and dluts (%DMDLFB)
  • Determination of the engine roughness correction value (%DMDFON, see )
  • Fuel-on correction of engine roughness values luts, fluts & dluts (%DMDLFK)
  • Misfire detection by luts-method
  • Misfire detection by dluts-method (%DMDDLU, see )
  • Misfire detection by flute-method (%DMDLUA, see )
  • Connection of misfire detection methods (%DMDLAD)
  • Fault handling and misfire statistics (%DMDMIL)
    • Notes
    • Emissions Relevant Misfires
      • Notes
      • Emissions Relevant Misfires after engine start
      • Emissions Relevant Misfires during driving cycle
    • Catalyst Damaging Misfires
  • Deactivation of the misfire detection (%DMDSTP)
  • Cylinder-bank deactivation because of voltage drop at all ignition coils
• Evaporative Purge System Diagnostic
  • Evaporative System Leak Measurement
    • Notes
    • General Description of Leak Measurement
    • Diagnosis Frequency and MIL Illumination
      • Diagnosis Frequency and MIL illumination: leak > 0.04 inches
      • Diagnosis Frequency and MIL illumination: Rough leak counter > threshold: leak > 0.02 inches
  • Evaporative Purge System - Canister Purge Valve (CPV)
    • Notes
    • Diagnosis of Canister Purge Valve (CPV) (under driving conditions)
• Secondary Air System Monitoring
• Diagnosis of fuel system
  • Notes
  • Fuel injection calculation
  • Fuel trim adaptation
  • Fuel system diagnosis
  • Near empty fuel tank functionality
  • Diagnosis of fuel system - summary error
• Oxygen sensor monitoring
  • Monitoring of the front oxygen sensor's heater power stage
  • Front oxygen sensor's heater control diagnosis
    • Notes
    • Calibration resistor check
    • Temperature check of the galvanic cell after engine start
    • Maximum heater output check
  • Rationality check of the front oxygen sensor
    • Notes
    • Maximum Fault
    • Minimum Fault
    • Plausibility fault
      • Notes
      • Method A1 - shift of characteristic lambda curve to leaner region
      • Method B1 - shift of characteristic lambda curve to leaner region
    • Signal Fault
      • Notes
      • Method A2 - shift of characteristic lambda curve to richer region
      • Method B2 - shift of characteristic lambda curve to richer region
    • In-Use monitor performance ratio (IUMPR)
  • Front oxygen sensor's response rate monitor
    • Notes
    • In-use monitor performance ratio (IUMPR)
  • Monitoring of the front oxygen sensor's voltage
  • Detection of exchanged front oxygen sensor connectors
  • Diagnosis of the evaluation IC of the front oxygen sensor
    • Notes
    • Open circuit - VM line interruption
    • Open circuit - UN line interruption
    • Open circuit - IA line interruption
    • Open circuit - IP line interruption
      • Notes
      • Detection during fuel cut off
      • Comparison with the set-point A/F ratio of the front oxygen sensor
    • Rationality check with the lambda controller factor
    • Short circuits to ground or to battery voltage
    • Monitoring of the communication between the Evaluation-IC CJ125 and the Micro-controller of the PCM
      • Implausible commands counter
      • Comparison of initialization and mirror register
    • Low supply voltage of the CJ125 IC
    • Electrical trimming
  • Diagnosis of electrical faults of the front oxygen sensor
  • Operation readiness of the rear oxygen sensor
    • Notes
    • Detection of short circuit to battery
    • Detection of short circuit to ground
    • Detection of an open circuit or a damaged sensor heating element
  • Diagnosis of the heating of the rear oxygen sensor
    • Notes
    • Internal resistance of the rear oxygen sensor's galvanic cell
    • Switching behavior of the rear oxygen sensor's heater power stage
  • Aging monitor of the rear oxygen sensor
    • Notes
    • Oscillation check
    • Threshold check during fuel cut-off
  • Monitoring of the rear oxygen sensor's response rate
  • Rear oxygen sensor's response rate monitor
• Exhaust Gas Recirculation (EGR) System Monitoring
• Positive Crankcase Ventilation (PCV) System
  • General description of the PCV-System
  • Diagnosis of a leakage in the PCV-System
• Engine Cooling System Monitoring
  • Diagnosis of ECT sensor
    • Notes
    • Circuit continuity check
    • Rationality checks
  • Diagnosis of Thermostat
• Cold start emission reduction strategy monitoring
  • Notes
  • Engine idle speed control (ISC)
  • In-Use monitor performance ratio (IUMPR)
• Air Conditioning (A/C) System Component Monitoring
• Camshaft and Crankshaft Sensor including Valve Timing
  • Camshaft Sensor
    • Variable Camshaft Timing (Vanos)
    • Vanos end position in range
    • Vanos reference position offset ("one tooth off")
    • Control deviation of the camshaft position controller (Target Error and Slow Response)
  • Valvetronic
    • Valvetronic Module
      • Notes
      • General description of this module
    • Valvetronic Power Supply
      • Notes
      • Description and diagnosis of this module
    • Valvetronic Power Stage
      • Notes
      • General description of this module
    • Valvetronic (limp-home)
      • Notes
      • Description and diagnosis of this module
• Comprehensive Component Monitoring
  • Fuel level sensor
    • Notes
    • Fuel level sensor circuit continuity check
    • Fuel level sensor signal rationality check (plausibility error)
    • FLS diagnosis frequency fuel level sensor circuit continuity check
    • FLS diagnosis frequency fuel level sensor signal rationality check (plausibility error)
  • Diagnosis of engine off time
    • Notes
    • CAN timersignal check
    • Rationality check
  • Diagnosis of ambient air temperature
    • Notes
    • CAN Signal Check
    • Range Check
    • Model based Rationality Check
    • Cold start Rationality Check
  • Diagnosis of atmospheric pressure sensor
    • Notes
    • Circuit continuity
    • Range check
    • Rationality check
  • Diagnosis of mass airflow sensor
    • Notes
    • Circuit continuity check
    • Range check of temperature compensation signal
    • Range check
    • Rationality check
  • Diagnosis of vehicle speed
    • Notes
    • Range check
    • Stuck check
    • Rationality check
  • Diagnosis of intake air temperature sensor
    • Notes
    • Electrical checks
    • Rationality checks
  • Engine speed sensor and camshaft position (CMP) sensor
    • Notes
    • Diagnosis of camshaft position sensor
      • Notes
      • Diagnosis by counting the CMP sensor signal edges
    • Diagnosis of engine speed sensor
      • Diagnosis by monitoring if the engine speed sensor signal is partly interrupted
      • Diagnosis by monitoring the camshaft position sensor (CMP) signal
      • Diagnosis by monitoring the engine speed sensor reference gap
  • Diagnosis of throttle position sensor
    • Notes
    • Range check
    • Rationality check
  • Diagnosis of the throttle valve's control unit
    • Notes
    • Impermissible deviations between requested and actual throttle position
    • Duty cycle range check
    • Throttle valve power stage check
  • Diagnosis of throttle body
    • Notes
    • Return spring check
  • Diagnosis of knock sensor
    • Notes
    • Circuit continuity check - via the CC 196 IC
    • Reference signal check
  • Diagnosis of knock control circuit
    • Notes
    • Pulse test
    • Zero Test
    • Parity Check
    • Sequence control of the monitors
  • Diagnosis of knock control serial port interface (SPI) monitoring
  • Diagnosis idle speed control (ISC)
    • Notes
    • Diagnosis during cold start
    • Diagnosis during warm operation
  • Diagnosis of battery voltage
    • Notes
    • Range check
    • Rationality check
  • Diagnosis of CAN Data Bus - TCM communication
    • Automatic Transmission
    • Semi-automatic transmission
  • Diagnosis of CAN Data Bus - VVT communication
  • Diagnosis of CAN signal timeout
    • Notes
    • Signal Fault
    • Minimum Fault
    • Plausibility Fault
  • Diagnosis of Local CAN B
  • Diagnosis of Powertrain CAN A and CAN C
• Identification of communication protocol utilized by engine N62 TUE 1 and N62TUE for communication with an SAE J1978 scan tool
• Listing of DME input and output signals
• Diagnosis of output stages
• In-use monitor performance ratio - kernel function
  • Notes
  • Ignition cycle counter
  • General denominator
  • IUMPR - Records
  • Incrementing the numerator and denominator
  • Minimum ratio selection (multiple monitors)
• Location of data link connector
  • For model 550i
  • For models 650Ci, 650Cic