DTC P0A14-14: Engine Mount "A" Control Circuit Low Circuit Short to Ground or Open [10/2022 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF VACUUM SWITCHING VALVE (FOR ACTIVE CONTROL ENGINE MOUNT SYSTEM))

Pre-procedure1

Disconnect the vacuum switching valve (for active control engine mount system) connector.
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
B8-1 (+B) - Body ground	Ignition switch ON	11 to 14 V	V

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

See step 4

Result:

See step 2

INSPECT VACUUM SWITCHING VALVE (FOR ACTIVE CONTROL ENGINE MOUNT SYSTEM)
Refer to INSPECTION [10/2022 - ]

Result

Proceed to

OK

NG

Result:

NG

REPLACE VACUUM SWITCHING VALVE (FOR ACTIVE CONTROL ENGINE MOUNT SYSTEM). Refer to REMOVAL [10/2022 - ]

Result:

OK

See step 3

CHECK HARNESS AND CONNECTOR (VACUUM SWITCHING VALVE (FOR ACTIVE CONTROL ENGINE MOUNT SYSTEM) - ECM)

Pre-procedure1

Disconnect the vacuum switching valve (for active control engine mount system) connector.
Disconnect the ECM connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
B8-2 (ACM) - B29-14 (ACM)	Always	Below 1 Ω	Ω
B8-2 (ACM) or B29-14 (ACM) - Body ground and other terminals	Always	10 kΩ or higher	kΩ

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

REPLACE ECM. Refer to REMOVAL [10/2022 - ]

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT EFI-MAIN NO. 3 RELAY
Refer to PROCEDURE - Step 5

Result

Proceed to

OK

NG

Result:

NG

REPLACE EFI-MAIN NO. 3 RELAY

Result:

OK

See step 5

CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 3 RELAY)

Pre-procedure1

Remove the EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
*2	EFI-MAIN NO. 3 Relay

Standard Voltage

Tester Connection	Condition	Specified Condition	Result
3 (EFI-MAIN NO. 3 relay) - Body ground	Always	11 to 14 V	V

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN NO. 3 RELAY)

Result:

See step 6

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 3 RELAY - BODY GROUND)

Pre-procedure1

Remove the EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
1 (EFI-MAIN NO. 3 relay) - Body ground	Always	Below 1 Ω	Ω

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 7

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 3 RELAY - VACUUM SWITCHING VALVE (FOR ACTIVE CONTROL ENGINE MOUNT SYSTEM))

Pre-procedure1

Remove the EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
Disconnect the vacuum switching valve (for active control engine mount system) connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
5 (EFI-MAIN NO. 3 relay) - B8-1 (+B)	Always	Below 1 Ω	Ω
5 (EFI-MAIN NO. 3 relay) or B8-1 (+B) - Body ground and other terminals	Always	10 kΩ or higher	kΩ

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN NO. 1 RELAY - EFI-MAIN NO. 3 RELAY)

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR