Lexus ES: High Voltage Power Resource Circuit Short during Ready ON (P1C8449)

Lexus ES (XZ10) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Control System (for Nickel Metal Hydride Battery) / High Voltage Power Resource Circuit Short during Ready ON (P1C8449)

DTC SUMMARY

MALFUNCTION DESCRIPTION

The hybrid vehicle control ECU monitors the high-voltage wiring between the HV battery and inverter with converter assembly and detects an open circuit malfunction.

HINT:

This DTC is differentiated from P300449 based on detection timing (after power switch is turned on (READY)). If P300449 is also output at the same time, first perform troubleshooting for P300449.
If there is a SMRG stuck open malfunction, only P1C8449 is output.

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

Inverter voltage sensor (VH or VL) internal circuit malfunction

Voltage sensor (VH or VL) malfunction
Motor generator control ECU (MG ECU) malfunction
Communication (wire harness) malfunction

High voltage system malfunction

HV battery malfunction
HV battery junction block assembly malfunction
Inverter with converter assembly malfunction
High-voltage wire harness malfunction
High-voltage connector or connection malfunction

Low-voltage circuit (12 V) malfunction

Hybrid vehicle control ECU malfunction
HV battery junction block assembly malfunction
Low voltage wire harness malfunction
Low voltage connector malfunction

DESCRIPTION

Refer to the description for DTC P0AE411.

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DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Warning Indicate
P1C8449	High Voltage Power Resource Circuit Short during Ready ON	High-voltage circuit malfunctions between the HV battery and inverter with converter assembly. The voltage before boosting continues to be out of the HV battery voltage range or the integrated value of variation amount of the voltage before boosting for a specified period of time is large while the power switch is on (READY). The EV electric battery fuse is blown, the service plug grip is removed, SMRB or SMRG remains open, or the high-voltage cable has an open circuit. (1 trip detection logic)	HV battery junction block assembly Wire harness or connector Hybrid vehicle control ECU	Comes on	Master Warning Light: Comes on

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

P1C8449

High Voltage Power Resource Circuit Short during Ready ON

High-voltage circuit malfunctions between the HV battery and inverter with converter assembly.

The voltage before boosting continues to be out of the HV battery voltage range or the integrated value of variation amount of the voltage before boosting for a specified period of time is large while the power switch is on (READY).

The EV electric battery fuse is blown, the service plug grip is removed, SMRB or SMRG remains open, or the high-voltage cable has an open circuit.

(1 trip detection logic)

HV battery junction block assembly
Wire harness or connector
Hybrid vehicle control ECU

Comes on

Master Warning Light:

Comes on

Related Data List

DTC No.	Data List
P1C8449	Hybrid Battery Voltage Hybrid Battery Current VL-Voltage before Boosting VH-Voltage after Boosting

The following items can be helpful when performing repairs:

Data List

Ready Signal

MONITOR DESCRIPTION

A malfunction is detected and the MIL is illuminated when the following condition is met:

A large fluctuation of DC/DC converter voltage is occurred due to power cable disconnection.

MONITOR STRATEGY

Related DTCs	P3004 (INF P1C8449): Power Cable Malfunction
Required sensors/components	DC/DC converter, HV battery
Frequency of operation	-
Duration	TMC's intellectual property
MIL operation	1 driving cycle
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not stored	TMC's intellectual property
Other conditions belong to TMC's intellectual property	-

TYPICAL MALFUNCTION THRESHOLDS

TMC's intellectual property

COMPONENT OPERATING RANGE

Hybrid vehicle control ECU

P3004 (INF P1C8449) is not detected

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.
Click here
When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
Click here

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 (IG) and turn the Techstream on.
Turn the power switch on (READY) and wait for 3 minutes or more. [*1]
HINT:
- According to the display on the Techstream, read the Data List and monitor the values of "Hybrid Battery Voltage" and "VL-Voltage before Boosting" for 3 minutes. If the difference between "Hybrid Battery Voltage" and "VL-Voltage before Boosting" is always less than 50 V, the vehicle has returned to normal.
- [*1] : Normal judgment procedure.
  The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
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 the normal judgment procedure again.

WIRING DIAGRAM

Refer to the wiring diagram for the HV Battery High-voltage Line Circuit.

Click here

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.
Click here

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, MOTOR GENERATOR)

(a) Connect the Techstream to the DLC3.

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

(d) Check for DTCs.

Powertrain > Hybrid Control > Trouble Codes Powertrain > Motor Generator > Trouble Codes

Result	Proceed to
P1C8449 only is output, or P0A9563 and DTCs except the ones in the table below are also output.	A
DTCs of hybrid control system in the tables below are output.	B
DTCs of motor generator control system in the tables below are output.	C
P0A9563 is also output.	D

Malfunction Content	System	Relevant DTC
Microcomputer malfunction	Hybrid control system	P0A1B49	Drive Motor "A" Control Module Internal Electronic Failure
		P060647	Hybrid/EV Powertrain Control Module Processor Watchdog / Safety MCU Failure
		P0AFC00	Hybrid/EV Battery Sensor Module
	Motor generator control system	P0A1B1F	Generator Control Module Circuit Intermittent
		P0A1A47	Generator Control Module Watchdog / Safety μC Failure
		P0A1A49	Generator Control Module Internal Electronic Failure
		P1C2A1C	Generator A/D Converter Circuit Circuit Voltage Out of Range
		P1C2A49	Generator A/D Converter Circuit Internal Electronic Failure
		P313383	Communication Error from Generator to Drive Motor "A" Value of Signal Protection Calculation Incorrect
		P313386	Communication Error from Generator to Drive Motor "A" Signal Invalid
Power source circuit malfunction	Hybrid control system	P0AFC16	Hybrid/EV Battery Sensor Module Circuit Voltage Below Threshold
Power source circuit malfunction	Motor generator control system	P06D61C	Generator Control Module Offset Power Circuit Voltage Out of Range
Communication system malfunction	Hybrid control system	P312387	Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message
	Hybrid control system	U029A87	Lost Communication with Hybrid/EV Battery Sensor Module Missing Message
	Motor generator control system	P313387	Communication Error from Generator to Drive Motor "A" Missing Message
Sensor and actuator circuit malfunction	Hybrid control system	P0ABF00	Hybrid/EV Battery Current Sensor "A" Circuit Range/Performance
		P0ABF11	Hybrid/EV Battery Current Sensor "A" Circuit Short to Ground
		P0ABF15	Hybrid/EV Battery Current Sensor "A" Circuit Short to Auxiliary Battery or Open
		P0ABF28	Hybrid/EV Battery Current Sensor "A" Signal Bias Level Out of Range / Zero Adjustment Failure
		P0ABF2A	Hybrid/EV Battery Current Sensor "A" Signal Stuck In Range
		P0AD911	Hybrid/EV Battery Positive Contactor Circuit Short to Ground
		P0AD915	Hybrid/EV Battery Positive Contactor Circuit Short to Auxiliary Battery or Open
		P0ADD11	Hybrid/EV Battery Negative Contactor Circuit Short to Ground
		P0ADD15	Hybrid/EV Battery Negative Contactor Circuit Short to Auxiliary Battery or Open
	Motor generator control system	P0D2D16	Drive Motor "A" Inverter Voltage Sensor (VH) Circuit Voltage Below Threshold
	Motor generator control system	P0D2D17	Drive Motor "A" Inverter Voltage Sensor (VH) Circuit Voltage Above Threshold
System malfunction	Hybrid control system	P0D2D1C	Drive Motor "A" Inverter Voltage Sensor Voltage Out of Range
		P0E311C	Boosting Converter Voltage Sensor "A" Voltage Out of Range
		P1C8349	High Voltage Power Resource Circuit Voltage Sensor after Boosting Malfunction
		P1C2D62	Hybrid/EV Battery "A" Voltage Sensor/Boosting Converter Voltage Sensor "A" Signal Compare Failure
		P300016	Hybrid/EV Battery Control System Circuit Voltage Below Threshold
		P300449	High Voltage Power Resource Circuit Short during Pre-Charge
	Motor generator control system	P1CB69E	Drive Motor "A" Inverter Voltage Sensor(VH) Stuck On
	Motor generator control system	P0CA300	DC/DC Converter Step Up Voltage Performance

HINT:

P1C8449 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)

GO TO DTC CHART (MOTOR GENERATOR CONTROL SYSTEM)

GO TO DTC CHART (P0A9563)

CLEAR DTC

Click here

3.	CHECK DTC OUTPUT (HYBRID CONTROL)

(a) Connect the Techstream to the DLC3.

(b) With the vehicle stopped, apply the parking brake and turn the power switch on (READY).

HINT:

If the power switch could not be turned on (READY), turn the power switch off and check for DTCs after turning the power switch on (READY) again.
Because P300449 uses 2 trip detection logic, the DTC detection conditions need to be met 2 times.

(d) Move the shift lever to D and depress both the accelerator pedal and brake pedal at the same time.

HINT:

Depressing both the accelerator pedal and brake pedal at the same time causes the HV battery current to flow and ensures that there is no problem with the high-voltage wiring.

(e) Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

(f) Check for DTCs.

Powertrain > Hybrid Control > Trouble Codes

Result	Proceed to
P1C8449 is output, or no DTCs are output.	A
Power switch could not be turned on (READY) and DTC P300449 is output.	B

(g) Turn the power switch off.

GO TO DTC CHART (P300449)

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

Click here

CONNECT SECURELY

5.	CHECK CONNECTOR CONNECTION CONDITION (FLOOR WIRE CONNECTOR)

Click here

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

6.	CHECK CONNECTOR CONNECTION CONDITION (HV BATTERY JUNCTION BLOCK ASSEMBLY CONNECTOR)

Click here

CONNECT SECURELY

7.	CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - HV BATTERY JUNCTION BLOCK 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) Remove the No. 1 HV battery cover panel RH.

Click here

(d) Disconnect the G59 hybrid vehicle control ECU connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
G59-4 (SMRB) - N22-1 (SMRB)	Power switch off	Below 1 Ω
G59-1 (SMRG) - N22-4 (SMRG)	Power switch off	Below 1 Ω

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

Front view of wire harness connector

(to HV Battery Junction Block Assembly)

(f) Reconnect the G59 hybrid vehicle control ECU connector.

(g) Reconnect the N22 HV battery junction block assembly connector.

(h) Install the No. 1 HV battery cover panel RH.

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.	CHECK HARNESS AND CONNECTOR (HV BATTERY JUNCTION BLOCK ASSEMBLY - BODY GROUND)

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) Remove the No. 1 HV battery cover panel RH.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N22-3 (GND) - Body ground	Power switch off	Below 1 Ω

*a	Front view of wire harness connector (to HV Battery Junction Block Assembly)

(e) Reconnect the N22 HV battery junction block assembly connector.

(f) Install the No. 1 HV battery cover panel RH.

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	REPLACE HV BATTERY JUNCTION BLOCK ASSEMBLY

Click here

10.	CHECK HYBRID VEHICLE CONTROL ECU (CHECK FOR NORMAL OPERATION)

CAUTION:

Be sure to wear insulated gloves.

(a) Install the service plug grip.

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

Click here

(d) Turn the power switch off and wait for 2 minutes or more.

(e) Turn the power switch on (READY).

(f) Enter the following menus: Powertrain / Hybrid Control / Data List / Hybrid Battery Voltage, VL-Voltage before Boosting.

(g) According to the display on the Techstream, read the Data List and monitor the values of "Hybrid Battery Voltage" and "VL-Voltage before Boosting" for 3 minutes.

Powertrain > Hybrid Control > Data List

Tester Display
VL-Voltage before Boosting
Hybrid Battery Voltage

Result	Proceed to
Difference between "Hybrid Battery Voltage" and "VL-Voltage before Boosting" is always less than 50 V.	A
Difference between "Hybrid Battery Voltage" and "VL-Voltage before Boosting" is 50 V or more.	B

(h) Turn the power switch off.

END

REPLACE HYBRID VEHICLE CONTROL ECU

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Lexus ES: High Voltage Power Resource Circuit Short during Ready ON (P1C8449)

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