DTC B227A-11: IGBD Circuit Short to Ground; DTC B227A-15: IGBD Relay Circuit Short to Auxiliary Battery or Open [12/2023 - ]: Procedure

WARNING: This page is about a different car, the 2024 Lexus TX 550h+. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT A/C-MAIN RELAY

Pre-procedure1

Remove the A/C-MAIN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher	kΩ
3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω	Ω

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*1	A/C-MAIN Relay

Result

Proceed to
OK
NG

Post-procedure1

Install the A/C-MAIN relay.

Result:

REPLACE A/C-MAIN RELAY

Result:

See step 2

CHECK HARNESS AND CONNECTOR (A/C-MAIN RELAY - BODY GROUND)

Pre-procedure1

Remove the A/C-MAIN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
1 (A/C-MAIN relay holder) - Body ground	Ignition switch off	Below 1 Ω	Ω

NOTE:

Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.

Result

Proceed to
OK
NG

Post-procedure1

Install the A/C-MAIN relay.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 3

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - NO. 2 ENGINE ROOM RELAY BLOCK AND NO. 2 JUNCTION BLOCK ASSEMBLY)

Pre-procedure1

Disconnect the hybrid vehicle control ECU assembly connector.
Remove the A/C-MAIN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
B88-48 (IGBD) -2 (A/C-MAIN relay holder)	Ignition switch off	Below 1 Ω	Ω
B88-48 (IGBD) or 2 (A/C-MAIN relay holder) - Body ground and other terminals	Ignition switch off	10 kΩ or higher	kΩ

Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition	Result
2 (A/C-MAIN relay holder) - Body ground	Ignition switch off	Below 1 V	V

Result

Proceed to
OK
NG

Post-procedure1

Install the A/C-MAIN relay from the No. 2 engine room relay block and No. 2 junction block assembly.
Reconnect the hybrid vehicle control ECU assembly connector.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 4

INSPECT HYBRID VEHICLE CONTROL ECU ASSEMBLY (IGBD TERMINAL VOLTAGE)

Pre-procedure1

Remove the A/C-MAIN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition	Result
2 (A/C-MAIN relay holder) - Body ground	Ignition switch ON	7.5 to 14 V	V

NOTE:

Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.

Result

Proceed to
OK
NG

Post-procedure1

Install the A/C-MAIN relay from the No. 2 engine room relay block and No. 2 junction block assembly.

Result:

GO TO AIR CONDITIONING SYSTEM. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2023 - ]

Result:

REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY. Refer to REMOVAL [12/2023 - ]