Lexus ES: Low or High Power Supply Voltage (C1241)

Lexus ES (XZ10) Service Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System (for Hv Model) / Low or High Power Supply Voltage (C1241)

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU (brake booster with master cylinder assembly) power source voltage drops, or there is insufficient voltage to operate the main relay, the skid control ECU (brake booster with master cylinder assembly) will store these DTCs.

If the auxiliary battery voltage is temporarily low, these DTCs may be stored.

HINT:

DTC C1256 (Accumulator Low Pressure) may also be memorized if there is a drop in power source voltage.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C1241	Low or High Power Supply Voltage	101 102 103 551 552 554	INF Code: 101 Either of the following is detected when the BS terminal voltage is 9.1 V or less: The brake is not applied for 3 seconds or more. The brake is applied for 0.05 seconds or more. INF Code: 102 Any of the following is detected when the ECU internal voltage is 6.92 V or less: The relay output voltage is less than 3.5 V for 0.05 seconds or more, when the main relay operation command is on. The stroke sensor value invalid for 0.2 seconds or more. The reaction force pressure sensor value invalid for 0.2 seconds or more. The servo pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more for 0.06 seconds or more. The servo pressure sensor value invalid for 0.2 seconds or more. The reaction force pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more for 0.06 seconds or more. INF Code: 103 When the ECU internal voltage is 8.3 V or less, the accumulator pressure sensor value is invalid for 0.8 seconds or more. Either of the following is detected when the ECU internal voltage is 6.9 V or less: When the accumulator pressure sensor value is 15 MPa (153 kgf/cm2, 2176 psi) or less, the pump motor does not operate for 1 second or more. Both the motor relay 1 and 2 cannot be operated for 0.2 seconds or more. INF Code: 551 Either of the following is detected when the BS voltage of the ABS unit is 9.1 V or less: The brake is not applied for 3 seconds or more. The brake is applied for 0.05 seconds or more. INF Code: 552 The speed sensor power voltage is invalid for 60 seconds or more. INF Code: 554 The voltage of IG1 or IG2 is 9.5 V or less for 10 seconds or more.	Improperly connected connector, deformation or corrosion of terminals Auxiliary battery Hybrid control system (Charging circuit) Skid control ECU (brake booster with master cylinder assembly) Wire harness or connector	Comes on	INF Code 101: SAE Code C14DE INF Code 102: SAE Code C1241 (Case 1 to 7) INF Code 103: SAE Code C1241 (Case 8 to 10) INF Code 551: SAE Code C14DB (Case 1 and 2) INF Code 552: SAE Code C1241 (Case 12) INF Code 554: SAE Code C1241 (Case 11) Electronically controlled brake system DTC

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

MIL

Note

C1241

Low or High Power Supply Voltage

101

102

103

551

552

554

INF Code: 101
- Either of the following is detected when the BS terminal voltage is 9.1 V or less:
  1. The brake is not applied for 3 seconds or more.
  2. The brake is applied for 0.05 seconds or more.
INF Code: 102
- Any of the following is detected when the ECU internal voltage is 6.92 V or less:
  1. The relay output voltage is less than 3.5 V for 0.05 seconds or more, when the main relay operation command is on.
  2. The stroke sensor value invalid for 0.2 seconds or more.
  3. The reaction force pressure sensor value invalid for 0.2 seconds or more.
  4. The servo pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more for 0.06 seconds or more.
  5. The servo pressure sensor value invalid for 0.2 seconds or more.
  6. The reaction force pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more for 0.06 seconds or more.
INF Code: 103
- When the ECU internal voltage is 8.3 V or less, the accumulator pressure sensor value is invalid for 0.8 seconds or more.
- Either of the following is detected when the ECU internal voltage is 6.9 V or less:
  1. When the accumulator pressure sensor value is 15 MPa (153 kgf/cm2, 2176 psi) or less, the pump motor does not operate for 1 second or more.
  2. Both the motor relay 1 and 2 cannot be operated for 0.2 seconds or more.
INF Code: 551
- Either of the following is detected when the BS voltage of the ABS unit is 9.1 V or less:
  1. The brake is not applied for 3 seconds or more.
  2. The brake is applied for 0.05 seconds or more.
INF Code: 552
- The speed sensor power voltage is invalid for 60 seconds or more.
INF Code: 554
- The voltage of IG1 or IG2 is 9.5 V or less for 10 seconds or more.

Improperly connected connector, deformation or corrosion of terminals
Auxiliary battery
Hybrid control system (Charging circuit)
Skid control ECU (brake booster with master cylinder assembly)
Wire harness or connector

Comes on

INF Code 101: SAE Code C14DE
INF Code 102: SAE Code C1241 (Case 1 to 7)
INF Code 103: SAE Code C1241 (Case 8 to 10)
INF Code 551: SAE Code C14DB (Case 1 and 2)
INF Code 552: SAE Code C1241 (Case 12)
INF Code 554: SAE Code C1241 (Case 11)
Electronically controlled brake system DTC

MONITOR DESCRIPTION

When the voltage at VM1, VM2, IG1, IG2 or BS drops due to a malfunction in the auxiliary battery and hybrid control system (charging circuit), the skid control ECU (brake booster with master cylinder assembly) judges that there is a drop in the power supply and illuminates the MIL and stores a DTC.

MONITOR STRATEGY

Related DTCs	C1241 (Case 1 to 11): Brake system voltage circuit low C1241 (Case 12): (Speed sensor voltage circuit low) C14DB: ABS solenoid power supply voltage circuit low C14DE: Main relay voltage circuit low
Required Sensors/Components(Main)	Brake pedal stroke sensor assembly Skid control ECU (brake booster with master cylinder assembly) Brake booster pump assembly Brake actuator assembly Brake actuator (brake booster with master cylinder assembly)
Required Sensors/Components(Related)	Speed sensor Skid control ECU (brake booster with master cylinder assembly)
Frequency of Operation	Continuous
Duration	-: C1241 (Case 6), C1241 (Case 7) and C14DE (Case 1) Within 1 second: C1241 (Case 1), C1241 (Case 2), C1241 (Case 3), C1241 (Case 4), C1241 (Case 5), C1241 (Case 8), C1241 (Case 9), C1241 (Case 10), C14DB (Case 2) and C14DE (Case 3) 3 seconds: C14DB (Case 1) and C14DE (Case 2) 10 seconds: C1241 (Case 11) 60 seconds: C1241 (Case 12)
MIL Operation	Immediately
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

C1241 (Case 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10)

Monitor runs whenever the following DTCs are not stored	None
Vehicle electric power supply	Stable state

C1241 (Case 11)

Monitor runs whenever the following DTCs are not stored	None
Both of the following conditions are met	-
IG1	On
Vehicle speed	Higher than 3 km/h (2 mph)

C1241 (Case 12)

Monitor runs whenever the following DTCs are not stored	None
IG1	On

C14DB

Monitor runs whenever the following DTCs are not stored	C146E (ABS solenoid power supply relay circuit low)
All of the following conditions are met	-
Vehicle electric power supply	Stable state
Command to ABS solenoid power supply relay	On
ABS solenoid power supply relay	On
ABS solenoid power supply relay fail (C146E)	Not detected

C14DE

Monitor runs whenever the following DTCs are not stored	C12FA (Main relay circuit low)
All of the following conditions are met	-
Vehicle electric power supply	Stable state
Command to main relay	On
Main relay	On
Main relay fail (C12FA)	Not detected

TYPICAL MALFUNCTION THRESHOLDS

C1241 (Case 1)

Both of the following conditions are met	-
Brake pedal stroke sensor assembly data	Invalid
Brake system voltage 1 (VM1)	6.92 V or less

C1241 (Case 2)

Both of the following conditions are met	-
Reaction force pressure sensor data	Invalid
Brake system voltage 1 (VM1)	8.27 V or less

C1241 (Case 3)

Both of the following conditions are met	-
Reaction force pressure sensor power supply	Less than 6.29 V, or higher than 7.64 V
Brake system voltage 1 (VM1)	8.27 V or less

C1241 (Case 4)

Both of the following conditions are met	-
Servo pressure sensor data	Invalid
Brake system voltage 1 (VM1)	8.27 V or less

C1241 (Case 5)

Both of the following conditions are met	-
Servo pressure sensor power supply	Less than 6.29 V, or higher than 7.64 V
Brake system voltage 1 (VM1)	8.27 V or less

C1241 (Case 6)

All of the following conditions are met	A, B and C
A. Power switch	Off
B. Either of the following conditions is met	-
Main relay	Off and there is on experience
ABS solenoid power supply relay	Off and there is on experience
C. Brake system voltage 1 (VM1)	6.92 V or less

C1241 (Case 7)

All of the following conditions are met	A, B, C and D
A. Power switch	On (READY)
B. Either of the following conditions is met	-
Main relay	Off and there is on experience
ABS solenoid power supply relay	Off and there is on experience
C. Brake system voltage 1 (VM1)	6.92 V or less
D. IG1 voltage	9.54 V or less

C1241 (Case 8)

Both of the following conditions are met	-
Accumulator pressure data	Invalid
Brake system voltage 2 (VM2)	8.27 V or less

C1241 (Case 9)

All of the following conditions are met	-
Serial communication with low side IC	Valid
Pump motor operating from IC	Enable
Accumulator pressure	Less than 15.3 MPa (156 kgf/cm2, 2219 psi) (Pump motor on pressure)
Brake system voltage 2 (VM2)	6.92 V or less

C1241 (Case 10)

All of the following conditions are met	-
Pump motor	Operating from IC
Pump motor voltage	Less than 6 V
Brake system voltage 2 (VM2)	6.92 V or less

C1241 (Case 11)

One of the following conditions is met	A, B or C
A. IG1 voltage	9.54 V or less
B. Both of the following conditions are met	-
IG2	On
IG2 voltage	9.54 V or less
C. Brake system voltage 1 (VM1)	7.54 V or less

C1241 (Case 12)

Both of the following conditions are met	-
Brake system voltage 1 (VM1)	7.54 V or less
Speed sensor power supply voltage (all of wheels)	Less than 6.1 V

C14DB (Case 1)

Both of the following conditions are met	-
Power supply for ABS solenoid	9.13 V or less
Brake control	Off

C14DB (Case 2)

Both of the following conditions are met	-
Power supply for ABS solenoid	9.13 V or less
Brake control	On

C14DE (Case 1)

All of the following conditions are met	A, B and C
A. Power supply for linear solenoid	9.13 V or less
B. Either of the following conditions is met	-
Linear solenoid (SLA) current drop signal	On
Linear solenoid (SLR) current drop signal	On
C. Brake control	On

C14DE (Case 2)

Both of the following conditions are met	-
Power supply for linear solenoid	9.13 V or less
Brake control	Off

C14DE (Case 3)

Both of the following conditions are met	-
Power supply for linear solenoid	9.13 V or less
Brake control	On

COMPONENT OPERATING RANGE

C1241 (Case 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10)

Both of the following conditions are met	-
Vehicle electric power supply	Stable state
Power supply common pass condition	Met

C1241 (Case 11)

All of the following conditions are met	-
Control valve solenoid	non-drive
IG1 voltage	Higher than 9.54 V
IG2 voltage	Higher than 9.54 V
Brake system voltage 1 (VM1)	Higher than 7.54 V

C1241 (Case 12)

Both of the following conditions are met	-
IG1	On
Brake system voltage 1 (VM1)	Higher than 7.54 V

C14DB

All of the following conditions are met	-
Vehicle electric power supply	Stable state
Command to ABS solenoid power supply relay	On
ABS solenoid power supply relay	On
ABS solenoid power supply relay fail (C146E)	Not detected
Power supply common pass condition	Met

C14DE

All of the following conditions are met	-
Vehicle electric power supply	Stable state
Command to main relay	On
Main relay	On
Main relay fail (C12FA)	Not detected
Power supply common pass condition	Met

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off.
Turn the power switch on (READY).
Turn the Techstream on.
Drive the vehicle at 10 km/h (6 mph) or more for 60 seconds or more.
Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
Read the DTCs.
HINT:
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
If the DTCs are not output, perform a universal trip and check for permanent DTCs.
Click here
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTCs are output, the system is normal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".
Click here
Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

CHECK DTC

(a) Check the DTCs that are output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
Only DTC C1241 is output.	A
DTC C1311 is output with DTC C1241.	B

GO TO DTC (C1311)

2.	CHECK AUXILIARY BATTERY

(a) Select the Data List on the Techstream.

for Nickel Metal Hydride Battery: Click here

for Lithium-ion Battery: Click here

Powertrain > Hybrid Control > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
BATT Voltage	Auxiliary battery voltage	Min.: 0.00 V, Max.: 16.00 V	11.00 to 15.00 V	BATT terminal

Powertrain > Hybrid Control > Data List

Tester Display
BATT Voltage

(b) Check the Techstream display condition of the auxiliary battery voltage.

Result	Proceed to
The auxiliary battery voltage is 11 to 15 V.	A
The auxiliary battery voltage is below 11 V.	B

CHARGE OR REPLACE AUXILIARY BATTERY

3.	CHECK FREEZE FRAME DATA

(a) Check the INF code from the Freeze Frame Data stored when DTC (C1241) was stored.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
INF code 101 or 551 is output.	A
INF code 102 or 552 is output.	B
INF code 103 is output.	C
INF code 554 is output.	D

GO TO STEP 5

GO TO STEP 6

GO TO STEP 7

4.	CHECK HARNESS AND CONNECTOR (BS TERMINAL)

(a) Turn the power switch off.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-52 (BS) - Body ground	Always	11 to 14 V

Result	Proceed to
11 to 14 V.	A
Below 11 V.	B

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (BS CIRCUIT)

5.	CHECK HARNESS AND CONNECTOR (IG1, +BI1 AND BS TERMINAL)

(a) Turn the power switch off.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-15 (+BI1) - Body ground	Power switch on (IG)	11 to 14 V
A45-52 (BS) - Body ground	Power switch on (IG)	11 to 14 V
A45-23 (IG1) - Body ground	Power switch on (IG)	11 to 14 V

Result	Proceed to
11 to 14 V.	A
Below 11 V.	B

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1, +BI1 AND/OR BS CIRCUIT)

6.	CHECK HARNESS AND CONNECTOR (IG1, IG2, +BI1, +BI2 AND BS TERMINAL)

(a) Turn the power switch off.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-15 (+BI1) - Body ground	Power switch on (IG)	11 to 14 V
A45-5 (+BI2) - Body ground	Power switch on (IG)	11 to 14 V
A45-52 (BS) - Body ground	Power switch on (IG)	11 to 14 V
A45-23 (IG1) - Body ground	Power switch on (IG)	11 to 14 V
A45-9 (IG2) - Body ground	Power switch on (IG)	11 to 14 V

Result	Proceed to
11 to 14 V.	A
Below 11 V.	B

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1, IG2, +BI1, +BI2 AND/OR BS CIRCUIT)

7.	CHECK HARNESS AND CONNECTOR (IG1 AND IG2 TERMINAL)

(a) Turn the power switch off.

*a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A45-23 (IG1) - Body ground	Power switch on (IG)	11 to 14 V
A45-9 (IG2) - Body ground	Power switch on (IG)	11 to 14 V

Result	Proceed to
11 to 14 V.	A
Below 11 V.	B

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 AND/OR IG2 CIRCUIT)

SEE MORE:

Removal

REMOVAL CAUTION / NOTICE / HINT The necessary procedures (adjustment, calibration, initialization, or registration) that must be performed after parts are replaced during forward recognition camera removal/installation are shown below. Necessary Procedure After Parts Removed/Installed/Replaced (for

Data List / Active Test

DATA LIST / ACTIVE TEST DATA LIST NOTICE: In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not. HINT: Using the Techstream to read the Data List allows the values or states of

Lexus ES: Low or High Power Supply Voltage (C1241)

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Open Circuit in IG1/IG2 Power Source Circuit (C1242)

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SEE MORE:

Removal

Data List / Active Test