|Realtime live display of the information the
electronic control unit of the selected vehicle system is currently
deriving from its input sensors.|
- Coolant Temperature (°C): This displays the coolant
temperature as measured by the ECU. The value should rise smoothly
during the engine warm up from the ambient temperature to approximately
85°C. A faulty temperature sensor may cause poor starting, fuel
consumption, fast idle speed and cooling fans to run continuously.
- Oil Temperature (°C): This displays the oil
temperature measured by the ECU. The value should rise smoothly during
the engine warm up from the ambient temperature to approximately 85°C. A
faulty temperature sensor may cause fuelling and idle speed problems.
- Inlet Air Temperature (°C): This displays the
temperature measured by the ECU using the inlet air temperature sensor.
The inlet air temperature is used by the ECU to retard the ignition
timing to avoid knock and trim the fuelling when hot. If the sensor is
not operating correctly the engine performance may be impaired slightly.
- Ambient Temperature (°C): This displays the ambient
temperature in the engine bay measured by the ECU using the ambient air
temperature sensor. This is done to control an extra engine bay cooling
fan on vehicles which require this. A faulty temperature sensor will
effect the normal operation of the cooling fan.
- Fuel Rail Temperature (°C): This displays the
temperature measured by the ECU using the fuel rail temperature sensor.
This reading is used by the ECU to make correction to fuelling and as an
aid to hot starting. A faulty sensor can alter the performance of the
engine and hot starting.
- Manifold Pressure (KPa): This displays the pressure
measured by the external MEMS air pressure sensor. Normal reading with
the engine not running is approximately 100 KPa and 30-40 KPa when the
engine is idling. Very high values may indicate problems with the sensor
or a blocked or disconnected vacuum pipe. Moderately raised values may
indicate mechanical problems with the engine.
- Throttle Angle (deg): This displays the position of
the throttle disc obtained from the MEMS ECU using the throttle
potentiometer. This value should change from a low value to a high value
as the throttle pedal is depressed. Accepted values are between 0 and
- Throttle Status: This displays the status of the
throttle position as received from the throttle position sensor. If the
switch shows open when the throttle is closed then the vehicle will not
idle correctly and the closed throttle position may need to be reset.
- Feedback (Oxygen Sensor Feedback Correction:
Display of the current feedback fuelling correction. This is shown as a
percentage of the mapped (open loop) value. This percentage is
continuously updated by the MEMS ECU whenever the conditions for closed
loop fuelling are present. Other times the feedback value will show 100%
indicating that closed loop fuelling is not operational. High values of
feedback (e.g.120%) indicate that feedback is at tempting to compensate
for fuelling being too lean and low values (e.g.80%) for fuelling being
too rich. Note: Misfire condition will be shown as high values as
feedback will be fooled into compensating for a system running too lean.
There are two values shown the first is for single sensor configurations
or Bank 1 in dual bank configurations and the second is for Bank 2 and
will show as 0 in single bank configurations.
- Oxygen Sensor: These values show the voltage across
the oxygen sensors as read by the MEMS ECU. Once the engine is fully
warm, during most idle and driving condition this voltage will be
alternating from above 2.025v to below 1.575v. The sensor detects the
presence or absence of oxygen in the exhaust gas. When the exhaust gas
has oxygen present the ECU will read a low voltage.
There are two
values shown, the first one displays the voltage of the single sensor in
single sensor configurations or the sensor serving bank 1. The second
voltage is the Bank 2 sensor and is only active in dual sensor
configurations. This always reads zero in single sensor configurations.
- Feedback States: This shows whether the fuelling is
being controlled using feedback from the oxygen sensors. On a fully warm
vehicle, the fuelling should be ACTIVE under most driving and idling
conditions. There are two values shown, the first one displays the
feedback state of the ECU in single sensor configurations or the
feedback state of bank 1 on dual bank (2 sensor) configurations. The
second displays the feedback control state of Bank 2 and is only active
in dual bank (2 sensor) configurations. This always reads OPEN in single
- Required Cam Period: This display the cam period
that the MEMS ECU is trying to achieve for a set of given driving
conditions. If the required and measured cam period do not closely
correspond this may indicate possible faults with the Vi mechanism.
- Measured Cam Period: This displays the current cam
period as measured by the MEMS ECU. If the required and measured cam
period do not closely correspond this may indicate possible faults with
the Vi mechanism.
- Ignition Switch: This shows the state of the
ignition switch as read by the MEMS ECU.
- A/C Switch: This shows the state of the air
condition request signal at the MEMS ECU. This signal depends on the
state of the air condition switch, the blower fan control, the air con
thermal switch and the trinary high/low pressure switch. The ECU will
not show air con on unless all of these switches are on. The thermal
switch will be off if the temperature of the air leaving the evaporator
is less than about 3 C and the high/low pressure switch will be off if
the pressure of the refrigerant is too high or too low.
- Drive Switch: This reading is valid only for
vehicles with automatic transmission. This shows the measured state of
the Park/Neutral switch. This switch is used to improve the quality of
engine idle speed control on automatic gearbox vehicles. A fault with
this switch will cause the idle speed to dip or rise suddenly when the
gear selection is changed between neutral and drive.
- Fan Request: This shows the ECU fan request input.
This input will be active if the air condition trinary medium pressure
switch is closed requesting that the ECU fan control is set to maximum
(fans on high speed).
- Battery Voltage: This shows the voltage of the
vehicle supply measured internally by the ECU. Large errors in this
measurement will lead to possible poor starting and errors in idle CO.
- Crankshaft Synchronisation: This shows the state of
the crank. This should read SYNCRONIZED when the engine is running.
- Camshaft Synchronization: This shows the state of
the cam. This should read SYNCRONIZED when the engine is running.
- Stepper Position (steps): This shows the position
of the IACV stepper motor as calculated by the ECU. The ECU has no
method of actually measuring this position but instead works it out by
remembering how may steps it has moved the steppers since the last time
the ignition was switched off. If a stepper motor fault exists this
number will be incorrect. This value will normally be changing during
idle conditions the ECU makes minor changes to the idle speed. A value
of 0 during idle conditions indicates a fault condition or poor
adjustment as does a very high value.
- Engine Speed: This shows the rotational speed of
the engine, calculated by the MEMS ECU using the crankshaft sensor.
Faults in the crankshaft sensor or associated wiring may be indicated if
this display reads 0 during engine cranking.