TPA400
TOYOTA PARKING AID 400
TROUBLESHOOTING GUIDE
Manual Ref. no. ATM 000 001-0
TPA400 - Troubleshooting with the multimeter
1. Before troubleshooting
In case a customer's TPA400 system is malfunctioning, these instructions can help you to find out what
the cause of the problem is. If you have an oscilloscope available, it's more advisable to use this tool
together with the "Troubleshooting with oscilloscope" instructions which will be available at the 2nd
quarter of 2004.
For the location of the parts described in this instruction, please refer to the TPA400 installation manual
for the concerning vehicle. The installation manuals are available on the training library.
In case verification of the actual detection zone of the installed TPA400 system is needed, sheets with
detailed information about the detection zone of each vehicle are available on the training library.
Following spare parts are available for TPA400 (please refer to the access to accessories website for
the correct P/N's):
ECU
Sensors Wire Harness
Unpainted sensor
Pre-primered sensor
Buzzer
Cut off switch
Owner's manual
Installation manual is available on the training library
All the procedures as described in this manual can be carried out without running engine.
Please refer also to the owner's manual (chapter B) where several conditions are listed under which
temporarily malfunction, reduced sensitivity range & detection failures can occur.
In case bumper removal is needed, always check during the removal whether the rubber caps of the
sensor wire harness are well installed on the sensors. An incorrect/incomplete installation of these
rubber caps might result in water ingress which can be the cause of the problem.
TPA400 - Troubleshooting with the multimeter 1
2. No activation of the system when reverse gear is selected.
When the system is operating normally, a confirmation beep is generated by the computer when the
reverse gear is engaged. In case this beep is not heard and/or the system does not detect objects,
following procedure should be followed to define the problem:
IGN ON
Shift to reverse
no
Is the cut-off switch (if present)
put cut-off
in "ON" position?
switch "ON"
yes
figure 1
no
Is the fuse on the power
replace fuse
wire OK? (refer to fig.1)
yes
Disconnect the 4-pin connector
Check the 4-
yes
(refer to fig.2) on the ECU and
pin connector
connect again. Shift to neutral
connection
and back to reverse.
Did the buzzer sound when
reconnecting?
figure 2
no
Check both the red and black wire of the power harness with the multimeter
(refer to fig.2). Is the readout as follows:
B+ (red wire): between 9 and 16V
B- (black wire): 0V
yes no
Go to step B
Go to step A
"system power analysis"
"Buzzer analysis"
TPA400 - Troubleshooting with the multimeter 2
A - Buzzer analysis
Disconnect the 2-pin connector
Check the 2-pin
from the ECU (refer to fig.3) and
yes
buzzer connector
connect again. Shift to neutral
connection
and back to reverse. Did the
buzzer sound?
no
figure 3
Remove the 2-pin connector and apply 12V on the buzzer connector from an
external source (B+ on the red wire and B- on the black wire). Does the buzzer
work?
yes
no
ECU failure, replace ECU
Buzzer failure, replace buzzer
TPA400 - Troubleshooting with the multimeter 3
B - System power analysis
Measure the voltage on the vehicle backup light
repair the
no
wire. Is the voltage between 9 and 16V? (Ensure
function of the
that the reverse gear is still engaged)
backup light
yes
Remove the cut-off switch connector or the cut-off switch loop
connector from the power wire harness (refer to fig.4). Check the
voltage on the connector, is the voltage on the incoming side
between 9 and 16V?
figure 4
yes
no
figure 5
Check with the multimeter whether the ground wire repair connection
is OK by holding one side to the black wire of the 4-
pin connector (refer to fig.5) and the other side to
the ground bolt of the vehicle. Is the ground wire
OK?
yes
no
repair connection
ECU failure, replace ECU
TPA400 - Troubleshooting with the multimeter 4
3. The buzzer doesn't stop sounding
In case the system is not able to detect obstacles due to sensor malfunctioning, the system will
generate a continuous intermittent tone with long beeps and short pauses (refer to fig.6).
IGN ON
Shift to reverse
figure 6
The buzzer emits a continual intermittent tone with long beeps and short
pauses as described in fig.6
yes
Go to step C "sensor malfunctioning"
The buzzer is constantly ON or is emitting a continual fast intermittent beep.
yes
Go to step D "continuous detection"
TPA400 - Troubleshooting with the multimeter 5
C - Sensor malfunctioning
yes
Touch the sensing part of each sensor (refer to
sensor OK
fig.7). Is this surface vibrating?
no
Disconnect the wire harness connector
yes
check ECU
of the defective sensor from the
connector
TPA400 ECU and reconnect. Is the
sensor surface vibrating now?
no
Disconnect the wire harness connector
of the defective sensor from the
yes
check sensor
defective sensor and reconnect. Is the
Figure 7
connector
sensor surface vibrating now?
no
Verify the continuity of the wires of the defective sensor with the multimeter.
Are the wires OK?
no
yes
TPA400 sensor wire harness
Make sure all wires are connected. Define the wire
failure, replace wire harness.
coming from a sensor with normal function (vibrating
surface). Remove this wire from the ECU and install
the wire of the defective sensor on this location. Is the
surface of the defective sensor vibrating now?
no
yes
ECU failure, replace ECU
Sensor failure, replace sensor
TPA400 - Troubleshooting with the multimeter 6
D - Continuous detection
Make sure there are
Are there any objects located within the detection
yes
no obstacles within
area of the vehicle
the detection zone.
no
no
yes
Is there any debris on the sensing portion of the remove debris
sensor?
no
Is the indication mark (refer to
install the sensor
fig.8) located on top of the sensor?
no
according to the
(unless specified differently in the
installation
installation manual)
instructions
yes
Figure 8
sensor malfunctioning, replace
sensor.
TPA400 - Troubleshooting with the multimeter 7
TOYOTA MOTOR CORPORATION