
1  Introduction
Congratulations  on  purchasing  the  new 
TYREGUARD 400 - TYRE PRESSURE MONITORING 
SYSTEM (TPMS). This system is a safety system 
for monitoring vehicle’s tyre air pressure and 
temperature. It consists of external mounted tyre 
pressure wireless sensors fitted to the vehicle’s 
tyre valve and a hand-held monitor. The sensor will 
monitor the tyre’s air pressure and temperature. The 
sensor transmits the tyre pressure and temperature 
information to the dash-mounted/hand-held monitor.
The monitor can be placed on the dashboard, on 
the sun visor or mounted in any convenient place in the vehicle.
2  Function
The monitor’s function is to receive the temperature and pressure information transmitted 
from a sensor fitted to each tyre and display this information on the screen in the specific 
units of measurement of your choice.
The monitor will emit an alarm when a tyre pressure or temperature varies markedly (refer 
pages 8-12) from the targeted tyre pressure and/or temperature. The system will detect 
high or low air pressure as well as high temperature or rapid leakage from the tyres. 
The monitor will flash the red LED icon and an alarm will sound to remind the operator 
to check if the tyres are high or low in air pressure, leakage, high temperature or the 
monitor’s battery is low, or there is a problem with a sensor. This advanced tyre monitoring 
system offers these great features and benefits, is reliable, lightweight and compact.
SENSOR
MONITOR
 
 

3  Installation & Operating Instructions
The following instructions show the identification of operating buttons of the monitor.
Units Conversion
Temperature Units Conversion
F=9C/5+32 
Note: C = Celsius; F = Fahrenheit 
Pressure Units Conversion 
1 Bar=14.5 psi 
1 Bar=100 kPa 
1 Bar=1.02 kgf/cm
2
PSI
KPa 
Bar
Kgf/cm
2
Pressure
sensor
monitor
TempLeaking
TEMPERATURE CONDITION icon
BATTERY CONDITION icon
Bar icon 
KPa icon
PSI icon
Kgf/cm
2
 icon
˚C icon 
˚F icon
NUMERICAL 
INDICATING 
SECTION
MONITOR icon
SENSOR icon
PRESSURE CONDITION icon
LEAKAGE icon
C 
F
Please ensure the monitor is fully charged and is in the tyre alignment mode before 
installing the tyre sensors.
Before installing sensors and setting the monitor, make sure you have inflated the 
vehicle’s tyres to your required pressures. 
Note: It is recommended to set tyre pressures at those recommended by the manufacturer 
listed in the vehicle’s handbook.
“→” button
“
→
” button
SET button
 
 

Tyre alignment mode
Hold down the “
→
” and “→” buttons simultaneously on the monitor for 5 seconds to enter 
tyre alignment mode, and press either “
→
” or “→” button to select the specific tyre that 
needs to be aligned. 
Screw a sensor to the tyre valve stem and the current pressure will be displayed against 
the corresponding flashing tyre icon on the screen. Once the tyre is aligned successfully 
the green light appears on the monitor. The red LED light appears on the monitor if the 
sensor hasn’t been aligned and “- - -” also appears on the monitor. 
Note: If the sensor is to be removed from one valve and fitted to another valve, you must 
delete the current setting on the monitor and realign this sensor to the new tyre. To delete 
an aligned sensor from a tyre, hold down the SET button for 5 seconds. 
When you exit the alignment mode, by again holding down the “
→
” and “→”, buttons 
simultaneously on the monitor for 5 seconds to check the pressures and temperatures, 
the monitor will indicate the data of the selected tyre. Click through to ensure all tyre 
pressures and temperature details are in accordance with your requirements. After your 
checks are completed, the backlight will go out and the monitor will indicate the tyre 
pressure of the selected tyre.
The monitor may initially show abnormalities until you have set your required pressures 
and units of measurement. These will be done in the Standard Pressure Setting and unit 
selection setting below.
 
 

Installation of the Sensor and anti-theft device
The sensor of TYREGUARD 400 has an anti theft ring 
to prevent the sensors being stolen. Firstly, place the 
anti-theft ring over the valve stem, with one side of the 
inner hexagon facing out, place the hexagon head 
of the sensor into the inner hexagon and then screw 
down the sensor; finally, place the inner hexagon 
screws of the anti-theft device and tighten with the 
key provided. Please refer to the right graphics A, B 
and C when installing the rings.
It’s very simple to install the sensors. Screw a sensor 
to each tyre valve stem as the picture shows.
Note:
1. Always install the sensor when the tyre is cold
2. Please check each tyre valve is not damaged.
3. Check to ensure there are no leaks and the sensors 
are firmly secured to each tyre valve.
Installation of the Monitor
The monitor can be mounted using the pedestal or brackets supplied. The monitor can 
be fixed to a suitable surface in the vehicle, sun visor, dashboard etc. It has a build-in 
lithium battery or you may wish to use a power source from within the vehicle’s power 
socket to charge or operate the monitor.
 
 

Standard Pressure Setting   
Hold down the SET button of 
the monitor for 5 seconds to 
enter into the setting mode, as 
the right graphic shows. Press 
“
→
” or “→” button to set the 
required pressure, and then 
quickly press the SET button 
to scroll through to the next the 
tyre and repeat this sequence 
to set the remaining tyres. 
After you have completed setting all the tyre pressures, then set your preferred units of 
temperature and pressure measurement, “kpa”, “Bar”, “PSI” and “kgf/cm2” for pressure units 
and “F” and “C” for temperature, by pressing the “
→
” or “→” button. The corresponding 
icon will flash when a certain tyre or unit measurement is chosen to be set.
Hold down SET button for 5 seconds to exit the Standard Pressure Setting mode.
Examination of the Tyre Condition 
During the standby mode, press “
→
” or “→” button to check the air pressure and 
temperature of the designated tyre. When you press the “
→
” button the monitor will scroll 
through the current pressure and temperature of each tyre, as graphics A & B below 
show. The indicating cycle is as follows: 
» pressure of the front left tyre →  
» temperature of the front left tyre → 
» pressure of the front right tyre →  
» temperature of the front right tyre →  
» pressure of back left tyre → 
» temperature of the back left tyre → 
» pressure of back right tyre →  
» temperature of the back right tyre → and so on.
When you press the “
→
” button the above indicating 
cycle is reversed. 
 
 

The monitor indicates “- - -“when a specific sensor’s 
alignment is lost from the monitor, as graphic C 
shows. Refer to Tyre Alignment Mode on page 3 
to realign sensor.
The monitor will indicate the “no S” signal whenever 
a sensor is either out of range or may be faulty, as 
graphic D shows.
Battery Capacity Indicator of the Monitor and 
Sensor
When the monitor is low on power, the battery icon and “MONITOR” 
icon on the screen flash, the buzzer gives a 10 second intermittent 
alarm. The monitor then sounds every 30 seconds within 5 minutes 
of total discharge. 
When a tyre sensor has low power, the battery icon and “SENSOR” 
icon together with the corresponding tyre icon flash on the screen and 
a 10 second intermittent alarm will sound. If the power of any of the 
sensors becomes too low, please replace the corresponding battery 
immediately.
Charging the Monitor
The built-in lithium battery of the monitor is rechargeable. Please connect the 12/24V DC 
charger into the port at base of the monitor, and 
then insert the adapter plug into the port of the 
vehicle’s 12/24V DC accessory port. The vehicle’s 
battery power will charge the monitor when the power supply of the vehicle is turned on. 
It takes approximately 6 hours to fully charge the monitor.
The battery icon flashes as shown in graphic A, B and C above.
The monitor will sound an alarm when fully charged. Graphic C will disappear after  
1 second.
Note: Please keep the monitor in a cool environment when charging.
ABC
monitor monitor monitor
 
 

Sensor battery replacement
Replace the corresponding sensor’s battery when 
the monitor indicates a low battery. Unscrew the 
plastic cap from the sensor, take out the battery 
and replace with a new button cell battery, (CR 
1632). Ensure the “+” terminal is touching the 
upper bracket. Screw down the cover. Please 
refer to the right graphic A, B and C
Note: 
1.  The battery model required for the sensors is 
a CR1632 button battery.
2.  The “+” and “-” pole of sensor battery must 
be placed in the correct position with the “+” 
terminal facing up; failure to do so may cause 
the sensor to burn out.
3.  In order to make sure that the battery is 
replaced correctly, enter tyre alignment mode 
and delete the alignment of the respective 
sensor and realign it again.
Power up
Quickly press SET button to enter into the stand-by mode at the power off state.
Note: Once the monitor is turned on, the information from all tyres can take up to 4 
minutes to be received in normal conditions. When the sensors are in an area of strong 
interference or in very cold conditions, the monitor may not receive the signal. Pull out the 
monitor’s antenna to increase the strength of the signal.
BATTERY
A
B
C
SENSOR SENSOR COPING
“+” POLE OF BATTERY
 
 

Power off
Hold down SET button for at least 8 seconds, and the monitor will automatically switch 
off. Please note: the system will first enter into the setting mode 5 seconds after holding 
down SET button, continue holding down the SET button for a further 3 seconds or more 
to power off the monitor.
Note: Whether the monitor is turned on or off, the sensor is always in standby mode.
Standby Time
The monitor is installed with an intelligent 15 minutes suspension device. The monitor 
turns into suspension status to save the power after the vehicles is switched off for more 
than 15 minutes. Once the vehicle is started, the monitor automatically turns on and 
connects to the vehicle’s sensors.
4  Warning Conditions
The TYREGUARD 400 possesses the two functions, monitoring tyre temperature and air 
pressure conditions of the vehicle’s tyres.
Rapid Leakage
When the air pressure of a tyre drops more than 0.2 Bar (3psi) within 
2 minutes, the monitor will give an alarm and the corresponding 
icon will flash on the monitor’s screen to indicate which tyre has the 
abnormal air pressure and its current air pressure. The air pressure 
icon will flash along with the flashing red LED on the monitor, as the 
right graphic shows.
 
 

Slow Leakage
When the air pressure of a tyre drops more than 0.2 Bar (3psi) 
within 2~10 minutes, the monitor will give an alarm and the 
corresponding icon will flash on the monitor’s screen to indicate 
which tyre has the abnormal air pressure and its current air 
pressure. The air pressure icon will flash along with the flashing 
red LED on the monitor, as the right graphic shows.
Note: Whether there is a fast or slow leak, the sensor will send 
a message to the monitor while driving or stationary.
High Temperature Warning: Level 1
When the temperature inside the tyre exceeds 75°C, the system 
will give a class 1 high temperature alarm and the monitor will 
indicate the position of the tyre with abnormal temperature and 
its current temperature. Abnormal temperature is indicated by 
the flashing red LED on the monitor and the temperature icon 
flashing on the screen, as the right graphic shows.
High Temperature Warning: Level 2
When the temperature inside the tyre exceeds 85°C, the system 
will give a class 2 high temperature alarm and the monitor will 
indicate the position of the tyre with abnormal temperature and 
its current temperature. Abnormal temperature is indicated by 
the flashing red LED on the monitor and the temperature icon 
flashing on the screen, as the right graphic shows.
 
 

Low Air Pressure Warning: Level 1
When the actual air pressure is equal to or falls below 85% of the 
set pressure the system will give an alarm and the monitor will 
indicate the position of the tyre with abnormal air pressure and 
its current air pressure. The low air pressure is indicated by the 
flashing red LED on the monitor and the pressure icon flashing 
on the screen, as the right graphic shows. 
Low Air Pressure Warning: Level 2
When the actual air pressure is equal to or falls below 75% of the 
set pressure the system will give an alarm and the monitor will 
indicate the position of the tyre with abnormal air pressure and 
its current air pressure. The low air pressure is indicated by the 
flashing red LED on the monitor and the pressure icon flashing 
on the screen, as the right graphic shows. 
Low Air Pressure Warning: Level 3
When the actual air pressure is equal to or falls below 50% of the 
set pressure the system will give an alarm and the monitor will 
indicate the position of the tyre with abnormal air pressure and 
its current air pressure. The low air pressure is indicated by the 
flashing red LED on the monitor and the pressure icon flashing 
on the screen, as the right graphic shows. 
 
 

High Air Pressure Warning
When the actual air pressure is equal to or greater than 120% of 
the set pressure the system will give an alarm and the monitor 
will indicate the position of the tyre with abnormal air pressure 
and its current air pressure. The high air pressure is indicated 
by the flashing red LED on the monitor and the pressure icon 
flashing on the screen, as the right graphic shows. 
Multi-Warning Indication
1.  When one tyre has numerous abnormalities at once, 
the monitor will indicate all the various abnormalities 
as the graphic at right shows.
2.  When there are abnormalities with two or more tyres 
at the same time, the respective tyre icons with the 
abnormalities will flash on the screen. Further, the 
current tyre reading being displayed, its tyre icon 
will flash more rapidly than the other icons, as the 
right graphic shows.
Slow
Slow
Fast
Bar
Pressure
 
 

Sensor Abnormality Indication
If the monitor can’t receive the signal from the sensors within 20 
minutes in standby mode, the alarm system will sound for 15 seconds 
along with the flashing LED on the monitor. The corresponding 
icon of the abnormal sensor will also flash and indicate with  
“no S” which indicates there is either a fault with the sensor, the 
sensor is damaged or the sensor is out of range. The system will 
alarm every 20 minutes if the monitor still can’t receive the signal 
from the sensor, as the graphic at right shows.
Note: When the monitor is off or in standby mode, the monitor will 
display “no S” instead of the detailed pressure and temperature 
readings. The monitor will indicate the correct readings within 4 minutes of activation.
Explanation
The monitor will give out a continuous alarm for 15 seconds with the flashing red LED and 
back lights for 5 minutes along with the corresponding faulty tyre icon flashing. Press the 
“
→
” or “→” button to stop this alarm. Shortly after, the back light will automatically go off. 
The system alarm will sound again after one hour to further remind the operator.
When a sensor is removed to inflate or deflate a tyre, this will cause the sensor to detect 
rapid and/or slow leakage because the sensor has suddenly detected zero pressure. 
The monitor will return to normal and the alarm will stop after the sensor is refitted within 
approximately 10 minutes.
If you wish to add further sensors to the monitoring system, i.e. fitting sensors to an 
additional caravan or trailer, etc. refer to procedure 3, Installation & Operating 
Instructions. 
 
 

5  Technical Specifications
Sensor
Working Temperature 
-20°C -- 85°C
Working Humidity
0 -- 95%
Dimension
23 x 21 x 21mm
Weight
9g 
Battery Voltage
3V DC (CR1632)
Battery Life
1 year
Standby Current
500nA
Working Current
6mA
Pressure Measure Range
0 Bar -- 10 Bar
Pressure Measure Precision
±0.3 Bar
Temperature Measure Range
-20°C -- 85°C
Temperature Measure Precision
±3°C
Signal Transmitting Frequency
433.92 MHz
Operating Distance
The monitor will detect a signal from each sensor up to 8.0 
metres. Beyond this distance a Booster (Part No. 1020) must 
be fitted. The booster will assist with the monitoring of tyres up 
to 18.0 metres from the monitor.
Monitor
Working Voltage
3V DC
Working Temperature
-20°C -- 60°C
Working Humidity
0 -- 90% 
Standby Current
0.1mA
Working Current
15 mA
Dimension
90 x 55 x 24mm
Signal Receiving Frequency
433.92 MHz
Color of Backlight
White
 
 

6  TYREGUARD Assembly
Description Quantity
Sensors Four (4)
Monitor One (1)
Bracket One (1)
12/24 V DC Cigarette Lighter Adapter One (1)
Sensor anti-theft security devices Four (4)
Hexagon Screw Four (4)
Hexagon Allen Key Two (2)
Guarantee Card One (1)
User Manual One (1) book
NOTE
1.  This system can efficiently monitor the air pressure and temperature of the vehicle’s 
tyres. 
2.  In order to avoid damage to this equipment, please do not attempt to disassemble 
any assembly.
3.  Your TYREGUARD 400 system has an automatic monitoring function, so there is no 
need to press “
→
” or “→” to read the information.
4.  Please contact Davies, Craig Pty Ltd.  
T: +61 (0) 3 9369 1234  
F: +61 (0) 3 9369 3456  
E: info@daviescraig.com.au  
or log on to our website www.daviescraig.com.au should you require further  
information.