PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-47
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-47V9 MR-372-J84-87B000$129.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
SYSTEM OPERATION
–The valves are activated approximately 1 minute after the vehicle has been running at a speed above 12 mph
(20 km/h).
–During driving, the valves emit signals every minute.
–The valves remain active for 15 minutes after the vehicle stops, then switch to standby mode.
–In standby mode, the valves emit signals only if they detect a pressure difference between two successive
measurements exceeding 68 mbar or if the pressure difference since last emitting exceeds 68 mbar (due to tyre
cooling).
–The tyres are considered to be cold when the vehicle speed has been zero for 1h 45 min.
–The minimum time for detection of a leak is approximately 15 minutes.
–The message Inflate tyres for motorway is displayed only if the vehicle travels at more than 102 mph (170 km/
h) (as an indication) for 3 minutes and the pressure on at least one of the tyres is 400 mbar less than the
recommended pressure at low speed. This message is inactive if the tyres are inflated to motorway pressure,
irrespective of the vehicle speed.
–Alert thresholds:
–over-inflation when cold = recommended pressure + 700 mbar,
–over-inflation when hot = recommended pressure + 850 mbar,
–under-inflation = recommended pressure - 400 mbar,
–serious under-inflation = recommended pressure - 600 mbar,
–imbalance = difference in pressure between the left-hand and right-hand wheels on the same axle greater
than 500 mbar.
–Information messages for the driver:
–Stop! Tyre puncture + STOP warning light + wheel concerned is highlighted on instrument panel display +
buzzer.
–Adjust tyre pressure + the wheel concerned is highlighted on instrument panel display.
–Inflate tyres for motorway + four wheels highlighted on instrument panel display.
–Tyre sensor fault + the wheel concerned is erased.
–Electronic fault + "Service" warning light + the four wheels concerned disappear from the instrument panel
display.
–No display of the tyre inflation pressure on the instrument panel on MEGANE II.
