Last Modified: 7-25-2017 6.8:8.0.
51 Doc ID: RM000000Y3N00EX
Model Year Start: 2007 Model: LS460 Prod Date Range: [09/2006 - ]
Title: BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1241/41,C1242/42; Low
Battery Positive Voltage; 2007 MY LS460 [09/2006 - ]
DTC C1241/41 Low Battery Positive Voltage
DTC C1242/42 Open in IG1 / IG2 Power Source Circuit
DESCRIPTION
These codes are memorized when the power source voltage for the skid control ECU drops or the voltage
for the ABS MAIN1 relay and ABS MAIN2 relay operation drops. The ABS MAIN1 relay and ABS MAIN2
relay are in the skid control ECU.
HINT:
DTC C1256/57 (accumulator low pressure) may be memorized if the power source voltage drops.
DTC INFORMATION DTC DETECTION CONDITION TROUBLE AREA
CODE CODE
C1241/41 81 Any of the following is detected in the ABS MAIN1
• Battery
relay line, when the vehicle is in the ON state:
• ABS MAIN1
1. With the ABS MAIN1 relay and the relay (Skid
relay contact ON, the voltage of relay control ECU
power supply terminal (BSO1) is below interior
8.9 V and the actual current, which is circuit)
supplied by the relay, does not reach • ABS MAIN2
the specified value at any of the linear relay (Skid
solenoids for 0.03 seconds or more. control ECU
2. With the ABS MAIN1 relay and the interior
relay contact ON, the voltage of relay circuit)
power supply terminal (BSO1) is below • Charging
8.9 V and the brake pedal is not system
depressed for 3 seconds or more. • Power source
3. When 0.05 seconds elapsed after ABS circuit
MAIN1 relay is turned on and the relay
contact is ON, the voltage of relay
power supply terminal (BSO1) is below
8.9 V and even one wheel is prohibited
from braking while depressing the
brake pedal.
4. While the ABS MAIN1 relay ON
continues, skid control ECU activation
power source input terminal (+BI1 or
+BI3) becomes lower than 9.1 V and
DTC INFORMATION DTC DETECTION CONDITION TROUBLE AREA
CODE CODE
the relay contact OFF continues for 0.2
seconds or more.
5. With the pressure sensor power supply
voltage (VCM) 4.7 V or less or 5.3 V or
more, skid control ECU activation
power source input terminal (+BI1 or
+BI3) in the relevant lines is 9.1 V or
less for 0.05 seconds or more.
Any of the following is detected in the ABS MAIN2
relay line, when the vehicle is in the ON state:
1. With the ABS MAIN2 relay and the
relay contact ON, the voltage of relay
power supply terminal (BSO2) is below
8.9 V and the actual current, which is
supplied by the relay, does not reach
the specified value at any of the linear
solenoids for 0.03 seconds or more.
2. With the ABS MAIN2 relay and the
relay contact ON, the voltage of relay
power supply terminal (BSO2) is below
8.9 V and the brake pedal is not
depressed for 3 seconds or more.
3. When 0.05 seconds elapsed after ABS
MAIN2 relay is turned on and the relay
↑ 82 contact is ON, the voltage of relay ↑
power supply terminal (BSO2) is below
8.9 V and even one wheel is prohibited
from braking while depressing the
brake pedal.
4. While the ABS MAIN2 relay ON
continues, skid control ECU activation
power source input terminal (+BI2 or
+BI4) becomes lower than 9.1 V and
the relay contact OFF continues for 0.2
seconds or more.
5. With the pressure sensor power supply
voltage (VCM2) 4.7 V or less or 5.3 V
or more, skid control ECU activation
power source input terminal (+BI2 or
+BI4) in the relevant lines is 9.1 V or
less for 0.05 seconds or more.
↑ 83 With the engine switch on (READY), the capacitor
• Battery
mode signal is received from the brake control
• Charging
power supply while the vehicle is driven at low
system
speed for 7 seconds or more, or the vehicle is
DTC INFORMATION DTC DETECTION CONDITION TROUBLE AREA
CODE CODE
driven at medium to high speed for 3 seconds or • Brake control
more. power supply
When any of the following is detected:
1. The voltage of terminal IG1 or IG2 is
3.5 V or more, and when the vehicle
speed is 3 km/h, the voltage of • Battery
terminal IG1 is 9.5 V or less for 10 • Charging
91
↑ seconds system
92
2. The voltage of terminal IG1 or IG2 is • Power source
3.5 V or more, and when the vehicle circuit
speed is 3 km/h, the voltage of
terminal (+BI1 or +BI3) or (+BI2 or
+BI4) is 9.1 V or less for 10 seconds
When any of the following is detected:
1. The voltage of terminal IG1 is 3.5 V or
more, and with the voltage of terminal
+BI1 activation power source input
terminal BI3 at 9.1 V or less, the front
wheel speed sensor RH and rear wheel
93 speed sensor LH power supply voltage
↑ ↑
94 decreases for 60 seconds or more
2. The voltage of terminal IG2 is 3.5 V or
more, and with the voltage of terminal
+BI2 or +BI4 at 9.1 V or less, the front
wheel speed sensor LH and rear wheel
speed sensor RH power supply voltage
decreases for 60 seconds or more
The power supply voltage is not applied to the IG1
• Power source
terminal (below 3.5 V), power supply voltage is
circuit
C1242/42 87 applied to the IG2 terminal (3.5 V or more), and
• Skid control
DI1 terminal voltage is 9.5 V or more for 4
ECU
seconds or more.
The power supply voltage is applied to the IG1
terminal (3.5 V or more), power supply voltage is
↑ 88 not applied to the IG2 terminal (below 3.5 V), and ↑
DI1 terminal voltage is 9.5 V or more for 4
seconds or more.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration
.
PROCEDURE
1. INSPECT BATTERY
(a) Check the battery voltage.
Standard voltage:
11 to 14 V
NG INSPECT CHARGING SYSTEM
OK
2. CHECK DTC
(a) Clear the DTCs .
(b) Turn the engine switch off.
(c) Turn the engine switch on (IG).
(d) Check that the DTCs (electronically controlled brake system and SFI system) are recorded.
Result
RESULT PROCEED
TO
DTCs (C1311/11, C1312/12, C1313/13, C1314/14 and SFI system malfunction) are not
A
output
SFI control system DTC is output B
DTCs (C1311/11, C1312/12, C1313/13 and C1314/14) are output C
B GO TO SFI SYSTEM
REPAIR CIRCUIT INDICATED BY OUTPUT
C CODE
A
3. CHECK HARNESS AND CONNECTOR (IG1, IG2, +BI1, +BI2, +BI3, +BI4
CIRCUIT)
(a) Disconnect the A19 and A21 ECU connectors.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:
TESTER CONNECTION SWITCH CONDITION SPECIFIED CONDITION
Engine switch on (IG) 11 to 14 V
A19-46 (IG1) - Body ground
Engine switch off Below 1 V
Engine switch on (IG) 11 to 14 V
A21-46 (IG2) - Body ground
Engine switch off Below 1 V
A19-43 (+BI1) - Body ground Always 11 to 14 V
A21-38 (+BI2) - Body ground Always 11 to 14 V
A19-29 (+BI3) - Body ground Always 11 to 14 V
A21-22 (+BI4) - Body ground Always 11 to 14 V
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR (IG OR DI CIRCUIT)
OK
4. CHECK HARNESS AND CONNECTOR (GND CIRCUIT)
(a) Disconnect the A19 and A21 ECU connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
TESTER CONNECTION CONDITION SPECIFIED CONDITION
A19-1 (GND) - Body ground Always Below 1 Ω
A21-1 (GND4) - Body ground Always Below 1 Ω
REPAIR OR REPLACE HARNESS OR
NG CONNECTOR (GND CIRCUIT)
OK
5. RECONFIRM DTC
(a) Clear the DTC .
(b) Turn the engine switch on (IG).
(c) After 2 minutes or more have elapsed, drive the vehicle 5 km/h (3 mph) or more for 20
seconds.
(d) Check if the same DTCs are recorded .
Result
RESULT PROCEED TO
DTCs (C1241/41 and C1242/42) are not output A
DTCs (C1241/41 and C1242/42) are output B
HINT:
If troubleshooting has been carried out according to the "PROBLEM SYMPTOMS TABLE", refer back
to the table and proceed to the next step .
B REPLACE SKID CONTROL ECU
A END
