Active Control Engine Mount System (Diagnostic Codes & Circuit Tests): Overview Lexus ES XV40 facelift

DESCRIPTION

A G sensor is installed on the front engine mount to detect vibration of the vehicle. The ECU uses signals sent from the G sensor to determine the vehicle condition, control the active control engine mount actuator, and detect malfunctions in the mount. If there is a malfunction in the G sensor, the ECU stops Active control engine mount operation.

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1. READ VALUE USING TECHSTREAM (G SENS VOL (1X)) Connect Techstream to DLC3. Start the engine and turn the tester on. Enter the following menus: Powertrain / E-ACM / Data List. Read the G Sensor Output Vol (1x) value. Standard voltage The voltage changes within the range of 0.11 to 4.46 V. NG --> See step 3 OK: Go to next step
2. READ VALUE USING TECHSTREAM (G SENSOR OUTPUT VOL (11X) AND G SENSOR STANDARD VOLTAGE) Connect Techstream to DLC3. Start the engine and turn the tester ON. Enter the following menus: Powertrain / E-ACM / Data List. Read the G Sensor Output Vol (11x). Standard voltage The voltage changes within the range of 0 to 5 V. Read the G Sensor Standard Voltage value. Standard voltage 1.94 to 3.08 V OK --> REPLACE ACTIVE CONTROL ENGINE MOUNT ECU NG: Go to next step
3. CHECK HARNESS AND CONNECTOR (ACTIVE CONTROL ENGINE MOUNT ECU - ACCELERATION SENSOR) Disconnect the A9 E-ACM ECU connector and B11 acceleration sensor connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Value VGS (A9-24) - SGV (B11-1) Below 1 ohms GL1 (A9-19) - SGRR (B11-3) Below 1 ohms GGND (A9-26) - SGND (B11-2) Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK POWER SOURCE CIRCUIT (ACCELERATION SENSOR) Disconnect the B11 acceleration sensor connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Specified Value SGV (B11-1) - SGND (B11-2) 4.5 to 5.2 V NG --> REPLACE ACTIVE CONTROL ENGINE MOUNT ECU OK --> REPLACE ACCELERATION SENSOR

The ECU receives information from the G sensor, ECM (engine speed, engine load ratio coolant temperature, and shift position) skid control ECU (vehicle speed), and A/C ECU (ambient temperature). Based on this information, the ECU drives the solenoid actuator that is built in the front mount to generate vibration that is opposite to the engine vibration in order to reduce engine vibration.

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1. PERFORM ACTIVE TEST BY TECHSTREAM (CHECK THE E-ACM) Connect Techstream to DLC3. Start the engine and turn the tester ON. Enter the following menus: Powertrain / E-ACM / Active Test. Check if the active mount control actuator operates. Standard The active mount control actuator operates normally. OK --> See step 4 NG: Go to next step
2. CHECK FRONT ENGINE MOUNTING INSULATOR (ACTIVE CONTROL ENGINE MOUNT ACTUATOR) Disconnect the B10 active control mount actuator connector. Measure the resistance between the ACT+ and ACT- terminals of the actuator connector. Standard resistance Tester Connection Specified Value ACT+ (B10-2) - ACT- (B10-1) 0.73 to 0.77 ohms ACT+ (B10-2) - Body ground 1 Mohms or higher ACT- (B10-1) - Body ground 1 Mohms or higher NG --> REPLACE FRONT ENGINE MOUNTING INSULATOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ECU - ACTUATOR) Disconnect the A9 active control engine mount ECU connector and B10 active control engine mount actuator connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Value ACT+ (A9-1) - ACT+ (B10-2) Below 1 ohms ACT- (A9-3) - ACT- (B10-1) Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE ACTIVE CONTROL ENGINE MOUNT ECU
4. CHECK ACCELERATION SENSOR. Refer to «DTC P16A0: G Sensor Circuit»(ref-396654-S18271901912011050900000)

If power source voltage drops, the control will stop because the ECU does not operate. If the power source voltage exceeds the specified level, the control is stopped to protect the actuator.

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1. CHECK ECU TERMINAL VOLTAGE (+B AND IG2 VOLTAGE) Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Value +B (A9-2) - Body ground Always 10 to 14 V IG2 (A9-10) - Body ground Engine switch on (IG) 10 to 14 V NG --> CHECK AND REPAIR HARNESS AND CONNECTOR (E-ACM AND IGN FUSE - ACTIVE CONTROL ENGINE MOUNT ECU) OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (ACM ECU - BODY GROUND) Disconnect the A9 active control engine mount ECU connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Value GND (A9-12) - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE ACTIVE CONTROL ENGINE MOUNT ECU

If the TACH signal cannot be detected and if the communication is interrupted, the ECU will stop controlling the E-ACM.

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1. CHECK TERMINAL VOLTAGE (TACH TERMINAL) Disconnect the A9 Active control engine mount ECU connector. Measure the voltage between the TACH terminal of the A9 Active control engine mount ECU connector and body ground. Standard Tester Connection Specified Value TACH (A9-16) - Body ground Correct waveform is as shown OK --> REPLACE ACTIVE CONTROL ENGINE MOUNT ECU NG: Go to next step
2. CHECK HARNESS AND CONNECTOR (ACTIVE CONTROL ENGINE MOUNT ECU - ECM) Disconnect the A9 active control engine mount (ACM) ECU connector and A10 ECM connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Value TACH (A9-16) - TACH (A10-15) Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE ECM

ECM skid control ECU and A/C amplifier intercommunicates with the active control engine mount ECU through the Controller Area Network (CAN). If there is a problem in this intercommunication, the active control engine mount ECU sets a DTC.