Inspection Procedure

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Check communication circuit inside ECU.

PREPARATION:

Disconnect the following ECU connectors in order from the top downward.

HINT:

Before disconnecting the next connector, be sure that disconnected ECU connector is reconnected.

DTC DETECTION ITEM

Disconnect ECU connector	Connector No.
Theft deterrent ECU	T5
Transponder key ECU	T9
Driver seat ECU	D28
Rear seat switch	R29
Rear LH seat ECU	R27
Driver door ECU	D25
Rear door LH ECU	R13
Rear door RH ECU	R14
Passenger door ECU	F17
Rear RH seat ECU	R26
Overhead J/B	06
Rain sensor	R6
Moon roof control ECU	M6

Fig 1: Checking Continuity Of Wire Harness Between Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CHECK:

Check the DTC every time each connector is disconnect.

OK:

DTC B1214 or B1215 is not output.

OK : Replace corresponding ECU (ECU for which DTC is deleted is defective.) (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).
NG : Go to next step.

Check for short circuit between ECUs.

PREPARATION:

Disconnect the following pairs of ECU connectors simultaneously, from the top downward.

HINT:

Before disconnecting the next connector, be sure that disconnected ECU connectors are reconnected.
The short circuit check can be preformed on the circuit by disconnecting it from the MPX communication bus circuit.

If DTC is deleted, this means that the circuit being checked is short circuited and it must be repaired.

DTC DETECTION ITEM

Disconnect ECU connector	Connector No.
Theft deterrent ECU Transponder key ECU	T5 T9
Transponder key ECU Driver door ECU	T9 D25
Driver door ECU Rear door LH ECU	D25 R13
Rear door LH ECU Rear door RH ECU	R13 R14
Rear door RH ECU Passenger door ECU	R14 F17
Gateway ECU Overhead J/B	G3 O6
Gateway ECU Rear RH seat ECU	G3 R26
Rain sensor Overhead J/B	R6 O6
Moon roof control ECU Overhead J/B	M6 O6

Fig 2: Checking Continuity Of Wire Harness Between Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CHECK:

Check the DTC every time a pair of connectors are disconnected.

OK:

DTC B1214 or B1215 is not output.

HINT:

If DTC is deleted when the overhead ECU is disconnected, check the overhead J/B. (See INSPECTION )

OK : Repair or replace corresponding wire harness.
NG : Go to next step.

Check for short circuit.

PREPARATION:

Disconnect the following connectors of ECU.

HINT:

Before disconnecting the next connector, be sure reconnect the ECU connector that is already disconnected.

DTC DETECTION ITEM

Disconnect ECU connector	Connector No.
Gateway ECU Overhead J/B	G3 O6
Gateway ECU Rear RH seat ECU	G3 R26
Rain sensor Overhead J/B	G3 O6
Moon roof control ECU Overhead J/B	M6 O6

Fig 3: Checking Continuity Of Wire Harness Between Connectors

CHECK:

Check whether or not there is +B short and GND short between the above connectors.

OK:

No +B short and GND short.

NG : Repair or replace corresponding wire harness.
OK : Replace gateway ECU (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).