Code C1241 Low Battery Positive Voltage Toyota
DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT BATTERY
INSPECT ECU-IG NO. 2 FUSE
READ VALUE USING INTELLIGENT TESTER (IG1 VOLTAGE VALUE)
RECONFIRM DTC
INSPECT SKID CONTROL ECU (IG1 TERMINAL)
INSPECT SKID CONTROL ECU (GND TERMINAL)
RECONFIRM DTC
DTC C1241/41 Low Battery Positive Voltage
Description
If the voltage supplied to the IG1 terminal is within the DTC detection range due to malfunctions in components such as the battery and alternator circuit, this DTC is stored.
DTC Code |
DTC Detection Condition |
Trouble Area |
C1241/41 |
When either of the following conditions is detected: 1. Both of the following conditions continue for at least 10 seconds.
- The vehicle speed is more than 3 km/h (2 mph).
- The IG1 terminal voltage is below 9.5 V.
2. All of the following conditions continue for at least 0.2 seconds.
- The solenoid relay remains on.
- The IG1 terminal voltage is below 9.5 V.
- The relay contact is open.
|
- Battery
- ECU-IG No. 2 fuse
- Charging system
- Harness or connector
- Master cylinder solenoid (Skid control ECU)
|
Wiring diagram
Inspection procedure
NOTICE:
When replacing the master cylinder solenoid, perform zero point calibration .
-
Check the battery voltage.
Standard voltage:
11 to 14 V
Result
Result |
Proceed to |
OK |
A |
NG |
1GR-FE |
B |
2UZ-FE |
C |
1VD-FTV |
D |
|
GO TO CHARGING SYSTEM (ON-VEHICLE INSPECTION) |
|
|
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GO TO CHARGING SYSTEM (ON-VEHICLE INSPECTION) |
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|
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GO TO CHARGING SYSTEM (ON-VEHICLE INSPECTION) |
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2.INSPECT ECU-IG NO. 2 FUSE |

-
Remove the ECU-IG No. 2 fuse from the main body ECU (cowl side junction block LH).
-
Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection |
Condition |
Specified Condition |
ECU-IG No. 2 fuse |
Always |
Below 1 ? |
|
REPLACE ECU-IG NO. 2 FUSE |
|
|
3.READ VALUE USING INTELLIGENT TESTER (IG1 VOLTAGE VALUE) |
-
Install the ECU-IG No. 2 fuse.
-
Connect the intelligent tester to the DLC3.
-
Turn the ignition switch to ON and turn the intelligent tester on.
-
Start the engine.
-
Enter the following menus: Chassis / ABS/VSC/TRC / Data List.
ABS/VSC/TRC
Tester Display |
Measurement Item/Range |
Normal Condition |
Diagnostic Note |
IG1 Voltage Value |
IG1 voltage value/min.: 0 V, max.: 255 V |
9.5 to 14.0 V |
- |
-
Measure the voltage output from the skid control ECU displayed on the intelligent tester.
OK:
The output voltage displayed on the intelligent tester is within 9.5 to 14.0 V.
-
Clear the DTCs .
-
Check if the same DTCs are output .
HINT:
Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.
Result
Result |
Proceed to |
DTC is output |
LHD |
A |
RHD |
B |
DTC is not output (When troubleshooting in accordance with the Diagnostic Trouble Code Chart) |
C |
DTC is not output (When troubleshooting in accordance with the Problem Symptoms Table) |
D |
|
REPLACE MASTER CYLINDER SOLENOID |
|
|
|
USE SIMULATION METHOD TO CHECK |
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|
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PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE |
|
|
A |
|
|
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REPLACE MASTER CYLINDER SOLENOID |
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5.INSPECT SKID CONTROL ECU (IG1 TERMINAL) |

-
Disconnect the A24 skid control ECU connector.
-
Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection |
Switch Condition |
Specified Condition |
A24-46 (IG1) - Body ground |
Ignition switch ON |
11 to 14 V |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
6.INSPECT SKID CONTROL ECU (GND TERMINAL) |

-
Disconnect the A24 and A25 skid control ECU connectors.
-
Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection |
Condition |
Specified Condition |
A24-1 (GND1) - Body ground |
Always |
Below 1 ? |
A24-32 (GND2) - Body ground |
Always |
Below 1 ? |
A25-4 (GND3) - Body ground |
Always |
Below 1 ? |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
-
Clear the DTCs .
-
Check if the same DTCs are output .
HINT:
Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.
Result
Result |
Proceed to |
DTC is output |
LHD |
A |
RHD |
B |
DTC is not output (When troubleshooting in accordance with the Diagnostic Trouble Code Chart) |
C |
DTC is not output (When troubleshooting in accordance with the Problem Symptoms Table) |
D |
|
REPLACE MASTER CYLINDER SOLENOID |
|
|
|
USE SIMULATION METHOD TO CHECK |
|
|
|
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE |
|
|
A |
|
|
|
REPLACE MASTER CYLINDER SOLENOID |
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