Tyre Pressure Monitoring System (Tpms) - Lotus Evora Service Notes

Lotus Service Notes
GJ.1 - GENERAL DESCRIPTION
The single piece, light alloy roadwheels are factory fitted with tyres engineered to provide the optimum
balance of ride and handling characteristics. In order fully to exploit the dynamic qualities and packaging op-
portunities, the wheel and tyre sizes are different front and rear, so that interchanging of wheels and tyres be-
tween axles is not permissible. Note that the tyre tread pattern is asymetric across the width, with the sidewalls
marked 'side facing inwards' or 'side facing outwards', but the tyre may rotate in either direction.
The tyres should be inspected frequently by the vehicle user, and also at every service, for signs of cuts,
abrasions or other damage, and for any uneven tread wear patterns. Uneven treadwear may indicate that the
suspension geometry or dampers require attention. Care should be taken when parking to avoid tyre contact
with high or sharp edged kerbs, as mistreatment of this nature can cause internal damage to the tyre structure
which may not readily be apparent. The alloy wheel rims may also be distorted or damaged by careless park-
ing, and result in wheel imbalance or loss of tyre pressure. Safety considerations should always be paramount
when assessing tyre condition and serviceability, and the tyres replaced if any doubt exists, or if the legal tread
depth limits are approached.
The cold tyre pressures should be checked every week, or every 1,000 miles (1,700 km), whichever is the
sooner, and corrections made as necessary. Under-inflation will cause excessive wear, rapid deterioration of
the tyre sidewalls and heavy steering, whereas overinflation results in a hard ride and increased susceptibility
to tyre damage. Both conditions will cause a degradation in the vehicle handling qualities. It is important that
the tyre pressures are adjusted only when the tyres are cold (driven less than one mile), as the pressures may
increase by 0.3 - 0.5 bar (4 - 8 lb/in²) when the tyres are warmed to normal running temperature. The tyre
valve dust cap should always be replaced in order to prevent the ingress of dirt and moisture into the valve,
which could cause leakage.
When balancing the wheel and tyre assemblies, the wheels should be located by the centre spigot - NOT
by the wheel bolt holes. In order to maintain the correct handling feel and minimum steering wheel shake, it is
very important that the radial and lateral run out of the tyres are to the high standard required by Lotus Cars.
If any difficulty is experienced with replacement tyres, refer to the tyre manufacturer.
The Yokohama Advan Sport tyres fitted to the Evora are suitable for all normal weather conditions. The
tyre characteristics include good feedback ('feel') from the road surface to the steering wheel, a high level of
steering linearity and response, and little performance degradation with the high temperatures which may be
reached in sports use. However, tyre performance will decrease at low ambient temperatures, resulting in
reduced levels of grip and an increased susceptibility to damage from impacts. In these conditions, especially
below -7°C, it is recommended to fit a car set of the recommended winter tyres (see below).
GJ.2 - TYRE PRESSURE MONITORING SYSTEM (TPMS) - Where fitted
A sensor incorporated into each of the tyre valves, monitors the air pressure inside the tyre, and supplies
an onboard control module located on the LH rear wheelarch with this data by radio transmission. Tyre pres-
sure information is displayed in the instrument cluster right hand screen. A silhouette of the vehicle showing
each wheel, will display all four tyre pressures for one minute following ignition switch on.
If any tyre pressure should fall below 75% of the recommended value, an alert message is sent to the
instrument panel, and the tyre pressure tell tale
houette will be highlighted and the pressure displayed.
If this warning should occur, the car should be stopped as soon as it is safely possible, and the affected
tyre examined. If there is no visible damage and a tyre pump is available, the pressure should be corrected
(see below), before proceeding with caution to a tyre repair/replacement facility. Note that the tell tale will
automatically be extinguished when the correct pressure is restored. If the tyre is punctured, or no inflation
equipment is available, use of the emergency tyre inflator aerosol (see below) should be considered, whilst
being aware that the TPMS sensor in the tyre would be disabled by the sealing fluid, and would subsequently
require replacement.
The TPMS incorporates self-malfunction recognition, and if a fault is detected, the low tyre pressure
tell tale in the instrument panel will flash for one minute, and then remain constantly lit, this sequence being
repeated for subsequent ignition cycles; with the tell tale flashing or lit, there may be no detection of low
tyre pressure.
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will light up amber. The corresponding tyre on the sil-
Section GJ