Discovery 2. Manual — part 370

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

88-28

DESCRIPTION AND OPERATION

Glow plug warning lamp

The glow plug warning lamp within the instrument pack utilises an amber LED and a clear legend. On vehicles with
diesel engines the LED illuminates when the ECM operates the glow plugs. After a predetermined time calculated by
the ECM, dependent on engine temperature, the LED is switched off providing the driver with a visible warning that
the engine can be started.

The power input for the LED is supplied by the instrument pack via fuse 27. The ECM provides the earth path to
illuminate the warning lamp.

The voltage on the earth path from the ECM to the instrument pack is as follows:

l

< 1.8 volts = warning lamp on.

l

> 7.7 volts = warning lamp off.