Lexus LS400 (2000 year). Service manual - part 18

BE–154

–

BODY ELECTRICAL

WIRELESS DOOR LOCK CONTROL SYSTEM

2017

Replace the transmitter battery with a new or normal
one and check UNLOCK–LOCK function works under
the standard operation.
<Reference>

 The battery should be replaced by only the shops with

sufficient skill as new or normal battery is necessary.

 Battery quality can be judged by checking the rem-

nant volume of the battery.

Yes

Battery faulty.

No

Make the vehicle be in the initialized condition.

Enter into the self diagnostic mode.
If operating door control receiver in the order of 1 through 2, the mode turns to diagnostic mode.
(1) Insert the key plate in the ignition key cylinder and pull out, then insert it again and turn ignition switch
OFF 

→

 ON 

→

 OFF once within 5 seconds after pulling out.

(2) After completing the procedure within 30 seconds, turn the ignition switch OFF 

→

 ON 

→

 OFF 9 times.

HINT:
In the case that either of (1) and (2) conditions is not satisfied, transfer to normal mode.
<Reference>
When completing self diagnostic mode, turn the ignition switch ON.
LOCK and UNLOCK operation and output of luggage door opener signal are not performed under the self
diagnostic mode.

1st time

9th time

ON

OFF

Transmitter battery check:

Inspection start by using self diagnostic mode:

within.
30 sec.

within.
5 sec.

1

2

3

9

10

Key plate
not inserted

Key plate
inserted

Ignition
switch

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BODY ELECTRICAL

WIRELESS DOOR LOCK CONTROL SYSTEM

BE–155

2018

No

No
(Not entered in self
diagnostic mode)

Is the method to enter into the
diagnostic mode correct?

Self diagnostic mode operation check:

Yes
(Entered in self diagnostic mode)

After the self diagnostic mode input operation has
been performed, check that the buzzer chirps.

ON

OFF

Buzzer

Ignition switch OFF

0.13 sec.

0.5 sec.

Is the chirping function of operation
confirmation buzzer normal?

Refer to chart 2.

Check that continuity exists between
connector terminal A3 of MPX body ECU
on the vehicle side and ground by
inserting the key plate into the ignition
key cylinder.

Key unlock warning switch inspection:

Yes

Yes

No

Check key unlock warning switch.

Self diagnostic mode check:

Check that how the buzzer chirps when pressing
each transmitter switch.

ON

OFF

Buzzer

0.13 sec.0.5 sec.

(1) Receiver normal wave of LOCK switch.

ON

OFF

Buzzer

0.13 sec.

0.25 sec.

(2) Receiver normal wave of UNLOCK switch.

0.5 sec.

ON

OFF

Buzzer

(3) Receiver normal wave of luggage door switch.

0.5 sec.

0.5 sec.

ON

OFF

(4) Incompatibility of the recognition code or out
from synchronization of rolling code.

While receiving

<Reference>:
While turning the ignition switch ON in the self
diagnostic mode, the mode returns to normal mode.

Buzzer

(1), (2) or (3) are output.

(4) is output.
(All buzzer’s response
are same.)

Recognition code registration function check:

Check that it is possible to enter into
rewrite mode or add mode.
(Refer to ”Wireless door lock receiver and
transmitter” – ”Recognition code registration”.)

Wireless door lock operate
normally when recognition code
is registered.

No response from buzzer.

BE–156

–

BODY ELECTRICAL

WIRELESS DOOR LOCK CONTROL SYSTEM

2019

Transmitter faulty or wireless door lock receiver
faulty.
<Reference>
Check the wave reaching range with another
transmitter (normal). When the range is normal,
transmitter defection is detected, the range is
not normal, wireless door lock receiver defection
is defected.

The wave reaching range check:

Is the wave reaching range normal?
(1 M area around vehicle)
(While the transmitting switch is pressed,
(approx. 20 secs.) the buzzer chirps continuously.
After 20 secs., repress the switch again.)

No

Other body control system faulty.
(Transmitter and receiver are normal.)

Yes

No

Wireless door control receiver check:

Check the diagnosis. (wireless door lock signal error)
(Refer to ”Multiplex communication system”)

Check that diagnostic code 42 is output.

Yes

Wire harness faulty (short circuit)
Between the receiver terminal 4 (RDA) and
body ECU terminal B14 (RDA).

Yes

RDA terminal open circuit.

No

Check RDA terminal circuit.

Check that the voltage of RDA is 10 to 14 V
(without transmitting).

No

When pressing each switch of
the new or normal transmitter
used in the same type vehicle,
check that all buzzers chirps
in the same way.

Transmitter faulty.

Yes

Using SST, connect terminal Tc and E1 of DLC1.

–

BODY ELECTRICAL

WIRELESS DOOR LOCK CONTROL SYSTEM

BE–157

2020

Wire harness faulty (open circuit)
Between the receiver terminal 3 (RCO) and
body ECU terminal B5 (RCO).

Yes

Wireless door control receiver power source check:

Check that there is 4.5 – 5.5 V voltage at the
connector terminal 3 (RCO) of wireless door control
receiver under the vehicle initialized condition.
(1) Check that the control receiver voltage becomes
0 V during transmitting.
(2) When RCO is turned ON compulsoring with a
LEXUS hand–held tester, check that the wireless door
lock control receiver voltage becomes 0 V.

No

ECU–B fuse or wire harness faulty.

Yes

+B power source check:

Check that there is constantly10 to 14 V voltage at the
connector terminal 7 (+B) of wireless door control
receiver.

No

Wire harness faulty.
Body ground open and contact error.

Yes

Body ground check:

Check that continuity exists between the connector
terminal 1 (GND) of the wireless door control receiver
and body ground.

No

Wireless door control receiver faulty.