BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1241,C1242; Low or High Power Supply Voltage; 2018 MY Camry HV [07/2017

Last Modified: 11-20-2023	6.11:8.1.0	Doc ID: RM1000000014VLS
Model Year Start: 2018	Model: Camry HV	Prod Date Range: [07/2017 - 09/2018]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1241,C1242; Low or High Power Supply Voltage; 2018 MY Camry HV [07/2017 - 09/2018]

DTC

C1241

Low or High Power Supply Voltage

DTC

C1242

Open Circuit in IG1/IG2 Power Source Circuit

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

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)

Electronically controlled brake system DTC

C1242

Open Circuit in IG1/IG2 Power Source Circuit

111

112

INF Code: 111
- When the IG1 terminal voltage is less than 3.5 V, the IG2 terminal voltage is 9.5 V or more for 4 seconds or more.
INF Code: 112
- When communication with the hybrid vehicle control ECU assembly is normal or the vehicle speed is 10 km/h (6 mph) or more, and the IG1 terminal voltage is 9.5 V or more, the IG2 terminal voltage is less than 3.5 V for 4 seconds or more.

INF Code: 111
- Open or short in IG1 circuit
- Improperly connected connector, deformation or corrosion of terminals
- Smart key system (IG start circuit)
- Auxiliary battery
- Hybrid control system (Charging circuit)
- Skid control ECU (brake booster with master cylinder assembly)
INF Code: 112
- Open or short in IG2 circuit
- Improperly connected connector, deformation or corrosion of terminals
- Smart key system (IG start circuit)
- Auxiliary battery
- Hybrid control system (Charging circuit)
- Skid control ECU (brake booster with master cylinder assembly)

Electronically controlled brake system DTC

DTC Detection Conditions: C1241 INF Code: 101

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	When the BS terminal voltage is 9.1 V or less.	○	○
Malfunction Status	The brake is not applied.	○	-
Malfunction Status	The brake is applied.	-	○
Detection Time		3 seconds or more	0.05 seconds or more
Number of Trips		1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

DTC Detection Conditions: C1241 INF Code: 102

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3	Pattern 4	Pattern 5	Pattern 6
Diagnosis Condition	When the ECU internal voltage is 6.92 V or less.	○	○	○	○	○	○
Malfunction Status	The relay output voltage is less than 3.5 V, when the main relay operation command is on.	○	-	-	-	-	-
	The value of the stroke sensor is invalid.	-	○	-	-	-	-
	The value of the reaction force pressure sensor is invalid.	-	-	○	-	-	-
	The servo pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more.	-	-	-	○	-	-
	The value of the servo pressure sensor is invalid.	-	-	-	-	○	-
	The reaction force pressure sensor power source voltage is 6.29 V or less, or 7.64 V or more.	-	-	-	-	-	○
Detection Time		0.05 seconds or more	0.2 seconds or more	0.2 seconds or more	0.06 seconds or more	0.2 seconds or more	0.06 seconds or more
Number of Trips		1 trip	1 trip	1 trip	1 trip	1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

DTC Detection Conditions: C1241 INF Code: 103

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3
Diagnosis Condition	ECU internal voltage is 8.3 V or less.	○	-	-
Diagnosis Condition	ECU internal voltage is 6.9 V or less.	-	○	○
Malfunction Status	The value of the accumulator pressure sensor is invalid.	○	-	-
	When the accumulator pressure sensor value is 15 MPa (153 kgf/cm², 2176 psi) or less, the pump motor does not operate.	-	○	-
	Both the motor relay 1 and 2 cannot be operated.	-	-	○
Detection Time		0.8 seconds or more	1 second or more	0.2 seconds or more
Number of Trips		1 trip	1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

DTC Detection Conditions: C1241 INF Code: 551

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	The BS voltage of the ABS unit is 9.1 V or less.	○	○
Malfunction Status	The brake is not applied.	○	-
Malfunction Status	The brake is applied.	-	○
Detection Time		3 seconds or more	0.05 seconds or more
Number of Trips		1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

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

1.	CHECK SMART KEY SYSTEM (for Start Function)

(a) Check if smart key system (for start function) DTCs are output.

Body Electrical > Smart Key > Trouble Codes

Body Electrical > Power Source Control > Trouble Codes

Result	Proceed to
DTCs are not output.	A
DTCs are output.	B

INSPECT SMART KEY SYSTEM (for Start Function)

2.	CHECK DTC (HYBRID CONTROL SYSTEM)

(a) Check if hybrid control system DTCs are output.

Powertrain > Hybrid Control > Trouble Codes

Result	Proceed to
DTCs are not output.	A
DTCs are output.	B

INSPECT HYBRID CONTROL SYSTEM

for Nickel Metal Hydride Battery: Click here

for Lithium-ion Battery: Click here

CHECK DTC

(a) Check that no main relay malfunction DTCs are output.

Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
Main relay malfunction DTCs are not output.	A
Main relay malfunction DTCs are output.	B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

4.	CHECK AUXILIARY BATTERY

(a) Check the auxiliary battery voltage.

Standard Voltage:

Tester Connection	Condition	Specified Condition
Auxiliary battery	Power switch on (IG)	11 to 14 V
Auxiliary battery	Power switch on (READY)	11 to 15.5 V

CHARGE OR REPLACE AUXILIARY BATTERY

5.	CHECK HARNESS AND CONNECTOR (POWER SOURCE 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
A40-15 (+BI1) - Body ground	Always	11 to 14 V
A40-5 (+BI2) - Body ground	Always	11 to 14 V
A40-52 (BS) - Body ground	Always	11 to 14 V
A40-23 (IG1) - Body ground	Power switch on (IG)	11 to 14 V
A40-9 (IG2) - Body ground	Power switch on (IG)	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

6.	CHECK HARNESS AND CONNECTOR (GND 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) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A40-26 (GND1) - Body ground	Always	Below 1 Ω
A40-39 (GND2) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

7.	RECONFIRM DTC

(a) Reconnect the A40 skid control ECU (brake booster with master cylinder assembly) connector.

(b) Clear the DTCs.

Chassis > ABS/VSC/TRAC > Clear DTCs

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

(e) Check if the same DTC is output.

Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
DTCs C1241 and C1242 are not output.	A
DTCs C1241 and/or C1242 are output.	B

USE SIMULATION METHOD TO CHECK

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY