Lexus ES: Motor/Generator Shutdown Signal Stuck Off (P321E9F)

Lexus ES (XZ10) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Control System (for Nickel Metal Hydride Battery) / Motor/Generator Shutdown Signal Stuck Off (P321E9F)

DTC SUMMARY

MALFUNCTION DESCRIPTION

The hybrid vehicle control ECU detects malfunctions which prevent the inverter with converter assembly emergency shutdown circuit (HSDN) from shutting down the hybrid control system. Detection is performed when the power switch is turned on (IG) and during the shutdown sequence when the power switch is turned off.

The cause of this malfunction may be one of the following:

Hybrid vehicle control ECU and inverter with converter assembly shutdown circuit malfunction

Hybrid vehicle control ECU malfunction
Connector or wire harness malfunction (between hybrid vehicle control ECU and inverter with converter assembly) malfunction
Inverter with converter assembly malfunction

DESCRIPTION

The hybrid vehicle control ECU sends a block signal to the motor generator control ECU (MG ECU) to shutdown the power supply to the motor. When the system is not in the on (READY) state, it sends an HSDN (MG shutdown signal) signal from the hybrid vehicle control ECU to the motor generator control ECU (MG ECU) to check the function of the HV gate block. When a malfunction is detected in the HV gate block function, DTCs are stored.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Warning Indicate
P321E9F	Motor/Generator Shutdown Signal Stuck Off	When the HV gate block function check is performed (when the power switch is turned from on (READY) to off), the inverter voltage (VH) drops and current flows in the inverter. (1 trip detection logic)	Wire harness or connector Hybrid vehicle control ECU Inverter with converter assembly	Does not come on	Master Warning Light: Comes on

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P321E9F

Motor/Generator Shutdown Signal Stuck Off

When the HV gate block function check is performed (when the power switch is turned from on (READY) to off), the inverter voltage (VH) drops and current flows in the inverter.

(1 trip detection logic)

Wire harness or connector
Hybrid vehicle control ECU
Inverter with converter assembly

Does not come on

Master Warning Light:

Comes on

Related Data List

DTC No.	Data List
P321E9F	VH-Voltage after Boosting Ready Signal Inverter Emergency Shutdown (Main CPU) Inverter Emergency Shutdown (Sub CPU)

CONFIRMATION DRIVING PATTERN

HINT:

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

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Connect the Techstream to the DLC3.
Turn the power switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for 2 minutes or more.
Turn the power switch on (READY) and wait for 30 seconds or more.
Turn the power switch off and wait for 2 minutes or more.
Turn the power switch on (READY) and wait for 30 seconds or more.
Turn the power switch off and wait for 2 minutes or more.
Turn the power switch on (IG) and turn the Techstream on.
Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.
Check the DTC judgment result.
HINT:
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or N/A, perform driving pattern again.

WIRING DIAGRAM

Refer to the wiring diagram for the shut down signal circuit.

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CAUTION / NOTICE / HINT

CAUTION:

Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.
- Inspecting the high-voltage system
- Disconnecting the low voltage connector of the inverter with converter assembly
- Disconnecting the low voltage connector of the HV battery
To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.
After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.
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HINT:

Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

*a

Without waiting for 10 minutes

NOTICE:

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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PROCEDURE

1.	CHECK DTC OUTPUT (HYBRID CONTROL)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Check for DTCs.

Powertrain > Hybrid Control > Trouble Codes

Result	Proceed to
P321E9F only is output, or DTCs except the ones in the table below are also output.	A
Any of the following DTCs are also output.	B

Malfunction Content	Relevant DTC
Sensor and actuator circuit malfunction	P33B99F	Motor/Generator Shutdown Signal (Hybrid/EV Side) Stuck Off
Sensor and actuator circuit malfunction	P33BF9F	Motor/Generator Shutdown Signal (MG Side) Stuck Off

HINT:

P321E9F may be output as a result of the malfunction indicated by the DTCs above.
1. The chart above is listed in inspection order of priority.
2. Check DTCs that are output at the same time by following the listed order. (The main cause of the malfunction can be determined without performing unnecessary inspections.)

(e) Turn the power switch off.

GO TO DTC CHART (HYBRID CONTROL SYSTEM)

2.	CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)

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CONNECT SECURELY

3.	CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR)

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Result	Proceed to
OK	A
NG (The connector is not connected securely.)	B
NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.)	C

CONNECT SECURELY

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - HYBRID VEHICLE CONTROL ECU)

CAUTION:

Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:

After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the A58 inverter with converter assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A58-22 (HSDN) - A33-12 (HSDN)	Power switch off	Below 1 Ω
A58-22 (HSDN) or A33-12 (HSDN) - Body ground and other terminals	Power switch off	10 kΩ or higher

HINT:

As there might be an intermittent malfunction, inspect the following items even if the measured resistance is as specified.

Check that each connector between the inverter with converter assembly and hybrid vehicle control ECU is not loose or disconnected.

Front view of wire harness connector

(to Inverter with Converter Assembly)

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

(e) Reconnect the A33 hybrid vehicle control ECU connector.

(f) Reconnect the A58 inverter with converter assembly connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK INVERTER WITH CONVERTER ASSEMBLY

CAUTION:

Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:

After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect the A58 inverter with converter assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A58-22 (HSDN) - A58-24 (GND1)	Power switch off	2.65 to 3.55 kΩ

NOTICE:

Be sure not to damage or deform the terminal being inspected.

*a	Component without harness connected (Inverter with Converter Assembly)

(d) Reconnect the A58 inverter with converter assembly connector.

REPLACE HYBRID VEHICLE CONTROL ECU

REPLACE INVERTER WITH CONVERTER ASSEMBLY

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