||MGF diagnostic tests and
Throttle Position Sensor Re-set
If the throttle body has been recently replaced, or you
find that the idle speed is a little on the high side, it may be worth
attempting to reset the throttle position sensor (TPS). This is readily achieved
by following the following procedure:
- Start engine and warm engine to its normal operating
temperature (essential, as when cold, the engine requires some extra air/fuel
- which on the MGF is managed by the idle air control valve: best not confuse
- Now turn off the ignition.
- Switch on the ignition to position II without starting
the engine (all the pre-start warning lights ought to be illuminated)
- Depress the throttle pedal to the carpet and fully
release inside a period of 30 seconds or so.
- Wait for about 15 seconds...
- Switch off the ignition
The engine can now be re-started; the TPS has been re-set.
Alarm system test
The alarm system can be tested by initiating the
alarm system test mode by following the procedure described below:
- Ensure doors, bonnet and the boot lid are
- Sit in the driverís seat and close the door.
NOTE: The next three actions must be
carried out within a couple of seconds of one another:
- Depress the driverís door lock-pin.
- Switch the ignition on, off and on again.
- Raise the driverís door lock-pin.
If the test mode has been entered
correctly, the horns will give a short beep and the engine immobilisation buzzer
- Opening either door, the bonnet or the boot
lid, or operating the driverís doorsill button, will cause the alarm LED to
illuminate for approximately one second. If the LED does not illuminate,
there is a system fault.
- The volumetric sensor can also be tested
while in test mode. To test the volumetric sensor, press the unlock
button on the remote handset several times. The alarm LED will illuminate for
approximately 1 second each time movement is detected in the vehicle.
The test mode is cancelled by switching
the ignition OFF.
Radiator Fan/ MEMS temperature sensor
If you find your MGF is over heating in slow
moving traffic, then a likely cause of this problem is a failure to operate the
radiator cooling fan. This is covered in more detail
here, but in
summary, to test to see whether the problem lies with the sensor or the fan:
- The radiator is typically inaudible from the
driver's seat, so a simple test to see whether it is working correctly, is to
switch on the engine and allow it to idle for 45 minutes. Normal engine
temperature is achieved within 30 minutes of idling, and within 45 minutes,
sufficient heat should build within the cooling system to require additional
cooling via the radiator. The cooling fan will either come on (audible from in
front of the car), OR the engine will start to over heat.
- Having established that the radiator is
failing to come on, remove the engine cover and disconnect the brown coloured
water temperature sensor that is located on the water outlet on the front left
hand corner of the engine. Whether hot or cold, doing this will immediately
start the fan. If not, either there is a problem with the fuses or the fan