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DESCRIPTION
The ABS solenoid relay supplies power to the ABS solenoid.
The solenoid relay is turned on 1.5 seconds after the ignition switch is turned
to the ON position, and is turned off if an open or short in the solenoid is
detected by self diagnosis performed when the vehicle starts running.
If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU,
with the ignition switch ON and the stop light switch off, the ECU performs self
diagnosis of the motor and solenoid circuits.
| DTC Code | Diag Code | DTC Detection Condition | Trouble Area |
| C0278 | 11 |
When either of the
following is detected:
|
• ABS SOL fuse • ABS SOL MAIN relay • ABS SOL MAIN relay circuit • Skid control ECU |
| C0279 | 12 | Immediately after the ignition switch is turned to the ON position, the solenoid relay contact is closed (AST terminal voltage is 4.8 V or more) for 0.2 seconds when the relay is turned off. | • ABS SOL fuse • ABS SOL MAIN relay • ABS SOL MAIN relay circuit • Skid control ECU |
WIRING DIAGRAM
Refer to DTCs C0226, C0236, C0246, C0256 and
C1227.
INSPECTION PROCEDURE
Detail
- Remove the ABS SOL fuse from the No. 2 relay block.
- Measure the resistance according to the value (s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition ABS SOL (30 A) fuse Always Below 1 Ω
REPLACE ABS SOL FUSE
[2] INSPECT ABS SOLENOID RELAY (ABS SOL MAIN)
- Install the ABS SOL fuse.
- Remove the ABS SOL MAIN relay.
- Measure the resistance according to the value (s) in the table below.
Tester Connection:
Tester Connection Condition Specified Condition 3-5 Voltage is not applied between terminals 1 and 2 10 kΩ or higher 3-5 Apply the battery voltage between terminals 1 and 2 Below 1 Ω
REPLACE ABS SOLENOID RELAY (ABS SOL MAIN)
[3] INSPECT NO. 2 RELAY BLOCK (POWER SOURCE TERMINAL)
- Measure the voltage according to the value (s) in the table below.
Standard voltage:
Tester Connection Condition Specified Condition ABS SOL MAIN relay terminal 5 - Body ground Always 20 to 32 V
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
[4] INSPECT BRAKE ACTUATOR ASSEMBLY
- Disconnect the brake actuator connector.
- Measure the resistance according to the value (s) in the table below.
Standard resistance:
Tester Connection Condition Specified Condition 16 (BS) - 10 (AST) Always Below 1 Ω 10 (AST) - Body ground Always 10 kΩ or higher
REPLACE BRAKE ACTUATOR ASSEMBLY
(See BRAKE ACTUATOR REMOVAL)
[5] CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR - NO. 2 RELAY BLOCK)
- Measure the resistance according to the value (s) in the table below.
Standard resistance:
Tester Connection Condition Specified Condition S22-16 (BS) - ABS SOL MAIN relay terminal 3 Always Below 1 Ω S22-16 (BS) - Body ground Always 10 kΩ or higher
REPAIR OR REPLACE HARNESS OR CONNECTOR
[6] CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE ACTUATOR)
- Disconnect the skid control ECU connector.
- Measure the resistance according to the value (s) in the table below.
Standard resistance:
Tester Connection Condition Specified Condition S11-6 (AST) - S22-10 (AST) Always Below 1 Ω S11-6 (AST) - Body ground Always 10 kΩ or higher
REPAIR OR REPLACE HARNESS OR CONNECTOR
[7] CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - NO. 2 RELAY BLOCK)
- Disconnect the skid control ECU connector.
- Measure the resistance according to the value (s) in the table below.
Standard resistance:
Tester Connection Condition Specified Condition S14-1 (R+) - ABS SOL MAIN relay terminal 2 Always Below 1 Ω S14-1 (R+) - Body ground Always 10 kΩ or higher S14-24 (SR) - ABS SOL MAIN relay terminal 1 Always Below 1 Ω S14-24 (SR) - Body ground Always 10 kΩ or higher
REPAIR OR REPLACE HARNESS OR CONNECTOR
[8] RECONFIRM DTC
- Clear the DTC (See Pub. No. S1-YXZE05A, page 05- 108).
- Start the engine.
- Drive the vehicle at a speed of 20 km/h (12 mph) or more
for 30 seconds or more.- Check if the same DTC is recorded (See Pub. No. S1-
YXZE05A, page 05-108).
Reinstall the relays, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.
Result:
Result Proceed to DTCs (C0278 and/or C0279) are not output A DTCs (C0278 and/or C0279) are output B
- If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU, with the ignition switch ON and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits.
- If the normal system code is output (the trouble code is not output), slightly jiggle the connectors, wire harness, and fuses of the skid control ECU and brake actuator assembly. Make sure that no DTCs are output.
- If any DTCs are output while jiggling a connector or wire harness of the skid control ECU and brake actuator assembly, inspect and repair the connector or wire harness.
- It is suspected that the DTCs were output due to a bad connection of the connector terminal.
A
CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)
(See DIAGNOSIS SYSTEM).B
REPLACE SKID CONTROL ECU.
- Confirm the DTC C0278 is inactive
- Start the engine and let it idling condition.
- Verify the DTC C0278 is inactive.
- DTC Clear
- Clear the DTC with Hino DX
- Confirm the same DTC is not reoccurred
- C0278 is reoccur: Return to first process
- Other DTC appear: Refer to concerned Trouble shooting
Complete
