LAUNCH    X-431 PRO Series User Manual 
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1. When the ABS contains air, the ABS bleeding function must be performed to 
bleed the brake system to restore ABS brake sensitivity. 
2. If the ABS computer, ABS pump, brake master cylinder, brake cylinder, brake 
line, or brake fluid is replaced, the ABS bleeding function must be performed 
to bleed the ABS. 
6.5 Tire Pressure Monitor System Reset 
This function allows you to quickly look up the tire sensor IDs from the vehicle’s 
ECU, as well as to perform TPMS replacement and sensor test. 
1. After the tire pressure MIL turns on and maintenance is performed, the tire 
pressure resetting function must be performed to reset tire pressure and turn 
off the tire pressure MIL. 
2. Tire pressure resetting must be performed after maintenance is performed in 
the  following  cases:  tire  pressure  is  too  low,  tire  leaks,  tire  pressure 
monitoring device is replaced or installed, tire is replaced, tire pressure sensor 
is  damaged,  and  tire  is  replaced  for  the  car  with  tire  pressure  monitoring 
function. 
6.6 Gear Learning 
The crankshaft position sensor learns crankshaft tooth machining tolerance and 
saves  to  the  computer  to  more  accurately  diagnose  engine  misfires.  If tooth 
learning is not performed for a car equipped with Delphi engine, the MIL turns on 
after the engine is started. The diagnostic device detects the DTC P1336 'tooth 
not learned'. In this case, you must use the diagnostic device to perform tooth 
learning for the car. After tooth learning is successful, the MIL turns off.   
After  the  engine  ECU,  crankshaft  position  sensor,  or  crankshaft  flywheel  is 
replaced,  or  the  DTC  'tooth  not  learned'  is  present,  tooth  learning  must  be 
performed. 
6.7 IMMO Service 
An immobilizer is an anti-theft mechanism that prevents a vehicle’s engine from 
starting  unless  the  correct  ignition  key  or  other  device  is  present.  Most new 
vehicles have an immobilizer as standard equipment. An important advantage of 
this system is that it doesn’t require the car owner to activate it since it operates 
automatically. An immobilizer is considered as providing much more effective 
anti-theft protection than an audible alarm alone. 
As an anti-theft device, an immobilizer disables one of the systems needed to