Description of Frozen Values, ECM

Description of frozen values

Explanation
Frozen values are parameter values that are stored when a diagnostic trouble code (DTC) is stored.
Not all parameters can be read off for all diagnostic trouble codes (DTCs). The parameter values can only be read off where they can provide more information about the prevailing circumstances when the diagnostic trouble code (DTC) was stored.

Total Mileage (km)
The value indicates the total distance covered by the vehicle at the time the Diagnostic Trouble Code (DTC) was generated.
Measurement range: 0 - 16777215 km.

MECU power supply (V)
The value indicates the voltage over the Central Electronic Module (CEM) when the Diagnostic Trouble Code (DTC) was generated.
Measurement range: 0 -64 V.
Normal range: 12.0 - 14.5 V.

Outside temperature (°C)
The value indicates the outside temperature at the time the Diagnostic Trouble Code (DTC) was generated.
Measurement range: -40 °C to +215 °C.

Power supply position, status
Indicates the current status of the power supply mode when the diagnostic trouble code (DTC) was stored.
Key removed
Key recently removed
Key approved
Ignition off after Accessory position
Accessory position
Accessory position after Ignition on
Ignition on
Running
Start attempts

Ignition switch (via CAN):
The engine control module (ECM) calculates the status of the signal from the central electronic module (CEM) via CAN communication.
Position 2 = Ignition switch in position 2 (ignition on).
Position 3 = Ignition switch in position 3 (start).
Engine running = Ignition switch in position 2 (ignition on) and engine running.

Brake pedal (via CAN) (%)
The engine control module (ECM) calculates the status of the signal from the brake control module (BCM) via CAN communication.

Engine speed (rpm)
The engine control module (ECM) calculates engine speed from the impulse sensor signal.

Boost pressure (hPa)
The value is calculated from the boost pressure sensor and indicates the pressure in the induction system after the turbocharger but before the throttle.
The engine control module (ECM) calculates boost pressure from the boost pressure sensor. The pressure is relative to atmospheric pressure.

Air mass (kg/h)
The value indicates the air mass that passes through the mass air flow sensor.
The engine control module (ECM) calculates the values from the mass air flow sensor signal.

Engine temperature (°C)
The engine control module (ECM) calculates temperature from the engine temperature sensor signal.

Engine temperature, start (°C)
The engine control module (ECM) calculates temperature from the engine temperature sensor signal. The value indicates the temperature of the engine upon engine start in the operating cycle in which the diagnostic trouble code (DTC) was generated.

Fuel pressure (kPa)
The engine control module (ECM) calculates the pressure from the fuel pressure sensor signal.
The parameter indicates absolute pressure.

Fuel temperature (°C)
The engine control module (ECM) calculates the temperature from the fuel temperature sensor signal.
The fuel temperature sensor is integrated in the fuel pressure sensor.

Calculated load (%)
The value, calculated by the engine control module, indicates engine efficiency. The engine control module (ECM) calculates the value from air mass, engine speed, boost pressure, throttle angle, etc. A value over 100% indicates turbocharging (overpressure).

Speed (km/h)
The value indicates vehicle speed.
The engine control module (ECM) receives information on vehicle speed from the brake control module (BCM) via CAN communication.

Ignition angle (°BTDC)
The value indicates the ignition angle for cylinder 1.

Ignition retardation, knocking (CA)
Ignition retardation requested to due cylinder knocking.
Measurement interval 0 - 72 CA.
Normal value 0 CA.
The value indicated is the average value for ignition retardation of all cylinders.
CA = Crank Angle.

Atmospheric pressure (hPa)
The value indicates atmospheric pressure at the engine control module (ECM).
The engine control module (ECM) calculates the value from the integrated atmospheric pressure sensor.
The normal value at 0 meters above sea level is 1013 hPa.

Intake air temperature (°C)
The engine control module (ECM) calculates the temperature from the intake air temperature sensor.

EVAP valve (%)
The value indicates the control module output signal for EVAP valve regulation, i.e. how much the EVAP valve should open to purge the canister.
0 % = no regulation (EVAP valve closed).
100 % = full regulation (EVAP valve fully open).

Throttle angle (%)
The engine control module (ECM) calculates the value from the throttle position sensor. The value is calculated linearly from the throttle position sensor's output signal (0-5V) and indicates how much the throttle is open.
Approx. 6-14 % = idling (0% throttle angle, desired value).
Approx. 85-100 % = throttle fully open (100% throttle angle, desired value).

Accelerator pedal position sensor, PWM (%)
PWM signal from the accelerator pedal position sensor to the engine control module (ECM). The control module calculates the value from the accelerator pedal position sensor's digital output.
The value indicates the position of the accelerator pedal.
Approximately 5 %= the accelerator pedal (AP) completely released.
Approximately 80 %= the accelerator pedal (AP) completely depressed.

Accelerator pedal position sensor, analog (%)
Analog signal from the accelerator pedal position sensor to the engine control module (ECM). The control module calculates the value from the accelerator pedal position sensor's analog output.
The value indicates the position of the accelerator pedal.
Approximately 5 %= the accelerator pedal (AP) completely released.
Approximately 80 %= the accelerator pedal (AP) completely depressed.

Throttle angle, desired value (%)
The value indicates the engine control module (ECM) calculated value for throttle opening (throttle angle).
The parameter value cannot be directly compared to the actual value for the throttle angle.
0% = idling.
100% = throttle fully open.

Fuel trim, quick adjustment, bank 1 (%)
Rapid adjustment is the continual adaptation of the fuel/air mixture during operation.
Bank 2 only applies to 6-cylinder engines.

Hint: Fuel trim returns to 0% once diagnostic trouble codes (DTCs) have been cleared.

Fuel trim, slow adjustment, bank 1 (%)
Slow adjustment is the fuel trim value that adjusts the fuel/air mixture for a longer period of time and factors in component aging, tolerances, etc.
Bank 2 only applies to 6-cylinder engines.

Hint: Fuel trim returns to 0% once diagnostic trouble codes (DTCs) have been cleared.

Front heated oxygen sensor, bank 1 (lambda)
The normal value is lambda = 1.
If the mixture is rich, lambda is less than 1.
If the mixture is lean, lambda is greater than 1.

Power supply, engine control module (ECM) (V)
The value indicates the power supplied to the engine control module (ECM).

Intake values, opening angle (CA)
The parameter corresponds to the "Camshaft shift angle" but is calculated from another reference position on the crankshaft.
The engine control module (ECM) calculates the value using signals from the impulse sensor (crankshaft position) and the camshaft sensor (camshaft position).
The value indicates when the intake valves open relative to top dead center (TDC) of the cylinders.
The value reduces the farther out the camshaft is guided.
When the camshaft is in its 0 position (camshaft not guided out), the angle is 27°CA; when it has been guided out fully the angle is -23°CA.
CA = Crank Angle.

Exhaust valves, closing angles (CA)
The parameter corresponds to the "Camshaft shift angle" but is calculated from another reference position on the crankshaft.
The engine control module (ECM) calculates the value using signals from the impulse sensor (crankshaft position) and the camshaft sensor (camshaft position).
The value indicates when the exhaust valves close relative to top dead center (TDC) of the cylinders. The value decreases as the camshaft is guided out.
When the camshaft is in its 0 position (camshaft not guided out), the angle is 26.5°CA; when it has been guided out fully the angle is -3.5°CA.
CA = Crank Angle.

Time after engine start (s)
The value indicates how much time has elapsed between engine start and diagnostic trouble code (DTC) generation.