Lexus RX300 (MCU15). Service manual — part 324

DI1AP–23

DI–528

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

LEXUS RX300 (RM785E)

PROBLEM SYMPTOMS TABLE

Symptom

Suspect Area

See page

Immobiliser is not set.

(Engine starts with key codes other than the registered key code.)

1. Engine & ECT ECU

IN–32

Engine does not start.

1. Key

2. Wire harness

3. Transponder key coil

4. Amplifier

5. Engine & ECT ECU

*1

IN–32

BE–190

IN–32

Security indicator is always ON.

1. Security indicator

2. Wire harness

3. Engine & ECT ECU

*2

IN–32

IN–32

Security indicator is always ON.

(Although code has been registered in the automatic registration

mode, indicator is not OFF.)

1. Wire harness

2 Tranxponder key coil

3. Amplifier

4. Engine & ECT ECU

IN–32

BE–190

IN–32

Security indicator is OFF

(When DTC of immobiliser is output)

1. Wire harness

2 Tranxponder key coil

3. Amplifier

4. Engine & ECT ECU

IN–32

BE–190

IN–32

Security indicator is OFF.

(When DTC of immobiliser is not output)

1. Wire harness

2. Engine & ECT ECU

IN–32

IN–32

Security indicator is abnormal blinking.

1. Wire harness

2. Engine & ECT ECU

IN–32

IN–32

*1 : Check that the key which did not start the engine has been registered and that it is possible to start with
other already registered key codes.
*2 : Finish the automatic registration mode because the mode might still remain.

DI1AS–22

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

DI–529

LEXUS RX300 (RM785E)

CIRCUIT INSPECTION

DTC

B2795/99 Unmatched Key Code

CIRCUIT DESCRIPTION

This DTC is output when an unregistered key is inserted. When this DTC is output, delete DTC and insert
the key that a customer keeps to check that B2795 is output.
When a key that outputs B2795 is found, register this key. when B2795 is not output, there is a possibility
that the unregistered key has been inserted before. (Engine & ECT ECU is normal.)
Inquire a customer the condition of using the system to find the cause of the trouble.
(Example: Another key has been inserted, etc..)

DTC No.

DTC Detecting Condition

Trouble Area

B2795/99

No communication

S Key

INSPECTION PROCEDURE

1

Delete DTC and insert all the presently available keys to check whether the en-
gine starts or not.

HINT:
When inserting the key that does not start the engine, DTC (B 2795) is stored in memory.

RESULT:

OK

All keys starts the engine.

NG

A specific key does not start the engine.

OK

No problem.

HINT:
If the result is ”OK”, please confirm whether or not customers
have ever inserted the unregistered key or the immobiliser key
(with transponder chip) of other vehicle in the ignition key cylin-
der, and find out the cause of detecting DTC.

NG

Register the key that does not start the en-
gine.

I03114

Engine and ECT ECU

CODE

RXCK

TXCT

18

19

E10

28

V

P

GR

4

3

2

T7
Transponder Key
Amplifier

E10

E10

CODE

RXCK

TXCT

DI–530

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

LEXUS RX300 (RM785E)

DTC

B2796/99 No Communication in Immobiliser system

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

B2796/99

No communication

S Key

S Transponder Key Coil

S Transponder Key Amplifier

S Wire harness

S Engine & ECT ECU

WIRING DIAGRAM

DI1AT–24

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

DI–531

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

1

Delete DTC and insert all the presently available keys to check whether the en-
gine starts or not

RESULT:

A

All keys start the engine.

B

A specific key does not start the engine. In this case, DTC

(B 2796) is stored in memory.

C

All keys do not start the engine. In this case, DTC (B 2796)

is stored in memory.

A

No problem at this time.

HINT:
If the result is ”A”, please confirm whether or not customers
have ever inserted the key (without transponder chip) of other
vehicle in the ignition key cylinder, and find out the cause of de-
tecting DTC.

B

The transponder chip of a specific key is defec-
tive. Replace the key.

C

2

Check transponder key coil (See page BE–190).

NG

Replace transponder key coil

OK

3

Check harness and connector between transponder key amplifier and engine &
ECT ECU.

NG

Repair or replace harness and connector

OK