ignition LAND ROVER DISCOVERY 1999 Workshop Manual

INSTRUMENTS
88-24 DESCRIPTION AND OPERATION
Traction control warning lamp
The traction control warning lamp within the instrument pack utilises a red LED and a clear legend. The traction control
warning lamp informs the driver that the traction control system is enabled. The warning lamp is hard wired to the
SLABS ECU. The SLABS ECU controls the warning lamp on or off via a high or low voltage signal to the instrument
pack.
When the ignition is switched on, the SLABS ECU illuminates the LED to provide a self-check, providing there is no
fault it will remain illuminated for 3 seconds or until the ignition is switched off.
The power input for the LED is supplied by the instrument pack via fuse 27. The SLABS ECU provides the earth path
to illuminate the warning lamp.
The voltage on the SLABS ECU earth path to the instrument pack is as follows:
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-25
Supplementary Restraint System (SRS) warning lamp
The SRS warning lamp within the instrument pack utilises a red LED and a clear legend. If a fault within the SRS is
detected, the SRS DCU illuminates the LED, providing the driver with a visible warning.
When the ignition is switched on, the SRS DCU illuminates the LED to provide a self-check, providing there is no fault
it will remain illuminated for 3 seconds or until the ignition is switched off. The SRS warning lamp does not output fault
codes.
The power input for the LED is supplied by the instrument pack via fuse 35. The SRS DCU provides the earth path to
illuminate the SRS warning lamp during the 3 second self-check.
The SRS warning lamp is switched on continuously by the instrument pack if the SRS DCU supply voltage is less than
half of the ignition switch voltage, with a tolerance of +2 or -1 volt.
The SRS warning lamp is operated by the SRS DCU if a fault is detected within the supplementary restraint system
circuits. The warning lamp is switched on according to the voltage present in the SRS DCU to instrument pack earth
path as follows:
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
88-26 DESCRIPTION AND OPERATION
Off road mode warning lamp
The off road mode warning lamp is available on vehicles equipped with self levelling suspension. The off road mode
warning lamp within the instrument pack utilises an amber LED and a clear legend. On vehicles fitted with self levelling
suspension the driver can enable the function using the off road mode fascia switch.
The SLABS ECU illuminates the LED, providing the driver with a visible warning.
When the ignition is switched on the SLABS ECU illuminates the LED to provide a self-check, providing there is no
fault it will remain illuminated for 3 seconds or until the ignition is switched off.
The off road mode is only enabled if the transfer box is in low range.
The off road mode warning lamp will flash at the rate of 2 Hz during the transition phase (up and down), and is
illuminated continuously when at full height.
The vehicle may be parked in off road mode the driver is reminded when the ignition is switched on that off road mode
is still active by the warning lamp flashing twice at a ratio 2 Hz then illuminates continuously.
The warning lamp will flash at 2 Hz in belly out mode. Belly out mode is if the vehicle grounds out, then the suspension
will raise to try and clear the underside of the vehicle.
If a new SLABS ECU is fitted the warning lamp remains illuminated until the ECU has been calibrated using TestBook.
The warning lamp will illuminate continuously if the voltage supply is less than 10 volts for 1 second.
The power input for the LED is supplied by the instrument pack via fuse 27. The warning lamp is switched on
according to the voltage present in the SLABS ECU to instrument pack earth path as follows:
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-27
Trailer warning lamp
The trailer warning lamp within the instrument pack utilises a green LED and a clear legend. When a trailer is fitted to
the vehicle, and the direction indicators are operated, the BCU detects additional current draw and illuminates the
LED, providing the driver with a visible warning.
When the ignition is switched on the BCU illuminates the LED to provide a self-check, providing there is no fault it will
remain illuminated for 3 seconds or until the ignition is switched off. This self-check is every time the ignition is
switched on, not only if a trailer is connected.
The power input for the LED is supplied by the instrument pack via fuse 13. The BCU provides the earth path to
illuminate the warning lamp.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-29
Water in fuel filter warning lamp
The water in fuel filter warning lamp within the instrument pack utilises an amber LED and a clear legend. On vehicles
with diesel engines the LED is illuminated when the water sensor detects water is present in the fuel filter, providing
the driver with a visible warning.
When the ignition is switched on, the instrument pack illuminates the LED to provide a self-check, providing there is
no water present in the fuel filter it will remain illuminated for 3 seconds or until the ignition is switched off.
The power input for the LED is supplied by the instrument pack via fuse 27. The water sensor provides the earth path
to illuminate the warning lamp. The voltage on the earth path from the sensor to the instrument pack is as follows:
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-31
Seat belt warning lamp
The seat belt warning lamp within the instrument pack utilises a red LED and a clear legend. The BCU utilises a switch
in each of the front seat belt buckles to determine if a seat belt is not fastened.
When the ignition is switched on, the BCU illuminates the LED for 6 seconds or until the BCU determines that a seat
belt is fastened which extinguished the warning lamp. This provides the driver with a visible reminder that the seat
belts are not fastened.
The instrument pack provides the self-check if the diagnostic connector fails.
The power input for the LED is supplied by the instrument pack via fuse 13. The BCU provides the earth path to
illuminate the seat belt warning lamp.
The seat belt buckle switches complete the earth path in the BCU sensing circuit, the BCU commands the instrument
pack to switch on the seat belt warning lamp.
The BCU earth path to the seat belt buckle is as follows:
l< 1.8 volts = warning lamp off.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
88-32 DESCRIPTION AND OPERATION
Transmission high temperature warning lamp
The transmission high temperature warning lamp within the instrument pack utilises a red LED and a clear legend.
On vehicles fitted with automatic gearboxes, the transmission high temperature warning lamp is utilised to provide the
driver with a visible warning that the automatic gearbox oil has exceeded a normal operating temperature. The
warning lamp will extinguish if the gearbox oil returns back to normal operating temperature.
When the ignition is switched on, the instrument pack illuminates the LED to provide a self-check, providing there is
no fault it will remain illuminated for 3 seconds or until the ignition is switched off.
The power input for the LED is supplied by the instrument pack via fuse 13. The temperature sensor provides the
earth path to illuminate the transmission high temperature warning lamp.
The transmission high temperature warning lamp is controlled according to the voltage present on the temperature
sensor to instrument panel earth path:
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-33
Engine oil pressure warning lamp
The engine oil pressure warning lamp within the instrument pack utilises a red LED and a clear legend. The LED
illuminates when the engine oil pressure is below the specified pressure (see table), providing the driver with a visible
warning that the engine oil pressure has fallen below the specified minimum reading.
There is no self-test performed at ignition on for this warning lamp.
The power input for the LED is supplied by the instrument pack via fuse 27. The oil pressure switch located on the
engine provides the earth path to illuminate the warning lamp, it will remain illuminated until the engine is started and
the oil pressure exceeds the appropriate threshold and opens the switch contacts.
Low oil pressure switch operating pressures
The response to the voltage signal at the instrument pack is as follows:
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.
Engine type Switch opening pressure, bar (lbf.in2)
V8 0.22 to 0.59 (3.0 to 8.5)
Diesel 0.25 to 0.42 (3.5 to 6.0)

INSTRUMENTS
88-34 DESCRIPTION AND OPERATION
Alternator charge warning lamp
The alternator charge warning lamp within the instrument pack utilises a red LED and a clear legend. The LED
illuminates when the alternator output voltage is less than 2 volts. When the alternator output is greater than 7.6 volts
the LED is extinguished, providing the driver with a visible warning that the alternator is charging.
When the ignition is switched on, and the LED illuminates, it will remain illuminated until the engine is started and
voltage is above the predetermined parameter, or the ignition is switched off providing there is no fault.
The power input for the LED is supplied by the instrument pack via fuse 27. The alternator provides a signal to
illuminate the warning lamp by means of a hard wired connection to the instrument pack.
The response to the voltage signal at the instrument pack is as follows:
l< 2.0 volts = warning lamp on.
l> 7.6 volts = warning lamp off.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-35
Hill Descent Control (HDC) fault warning lamp
The HDC fault warning lamp within the instrument pack utilises an amber LED and a clear legend. On vehicles fitted
with hill descent control the SLABS ECU illuminates the LED if a fault within the HDC system is detected, providing
the driver with a visible warning.
When the ignition is switched on, the SLABS ECU illuminates the LED to provide a self-check, it will remain illuminated
for 3 seconds or until the ignition is switched off, providing there is no fault.
The power input for the LED is supplied by the instrument pack via fuse 27. The SLABS ECU provides the earth path
to illuminate the HDC fault warning lamp
The voltage on the earth path from the SLABS ECU to the instrument pack has the following functions:
l< 1.8 volts = warning lamp is switched on.
l> 7.7 volts = warning lamp is switched off.