C1246 ABNORMALITY OF ABS ACTUATOR: BRAKE FLUID PRESSURE SENSOR

1. Set the starter switch to "ON", measure the voltage between 24th and 15th terminal of the 28 pin connector of ECU. (Leaving the connector connected with ECU.)
   Standard: 4.5-5.5V
   
   
   　

Go to the item "5".

[1]-2

2. Measure the voltage between 24th and 14th terminal of the 28 pin connector. (Leaving the connector connected with ECU.)
   Standard: 4.5-5.5V
   
   

Go to the item "5".

[2] WIRE HARNESS CHECK

1. Turn the starter switch to "LOCK", disconnect the 28 pin connector of ECU and the 3 pin connector of ABS actuator.
2. Measure the resistance between 25th terminal of the 28 pin connector of ECU (chassis harness side) and 2nd terminal of the 3 pin connector of ABS actuator (chassis harness side).
   Standard: Less than 5 Ω
   
   

Abnormality of the wire harness.

[3] ABS ACTUATOR CHECK

1. Connect all the connector, turn the starter switch to "ON".
2. Measure the voltage between 25th and 15th terminals of the 28 pin connector of ECU when depressing the brake pedal. (Leaving the connector connected with ECU.)
   Standard:
   0 MPa {0 kgf/cm², 0 lbf/in.²}: Approx. 0.5V
   9.8 MPa {100 kgf/cm², 1,442 lbf/in.²}: Approx. 2.5V
   19.6 MPa {200 kgf/cm², 2,845 lbf/in.²}: Approx. 4.5V
   
   

Abnormality of the ABS actuator.

[4] ECU CHECK

1. Measure the voltage between 24th terminal of the 28 pin connector of ECU and 2nd terminal of the 31 pin connector of ECU. (Leaving the connector connected with ECU.)
   Standard: 4.85-5.15V
   
   
   　

Abnormality of the ECU.

[4]-2

2. Measure the voltage between 25th terminal of the 28 pin connector and 2nd terminal of the 31 pin connector. (Leaving the connector connected with ECU.)
   Standard: 0.3-0.7V
   
   
   　

Abnormality of the ECU.

[4]-3

3. Turn the starter switch to "LOCK", check the continuity between 15th terminal of the 28 pin connector and 2nd terminal of the 31 pin connector. (Leaving the connector connected with ECU.)
   Standard: Continuity
   
   

Abnormality of the ECU.

[4]-4

4. Check the continuity between 14th terminal of the 28 pin connector and 2nd terminal of the 31 pin connector. (Leaving the connector connected with ECU.)
   Standard: Continuity
   
   

Abnormality of the ECU.

Normal.

1. Turn the starter switch to "LOCK", disconnect the 28 pin connector of ECU and the 3 pin connector of ABS actuator.
2. Measure the resistance between 24th terminal of the 28 pin connector of ECU (chassis harness side) and 1st terminal of the 3 pin connector of ABS actuator (chassis harness side).
   Standard: Less than 5 Ω
   
   
   　

Abnormality of the wire harness.

[5]-3

3. Measure the resistance between 15th terminal of the 28 pin connector of ECU (chassis harness side) and 3rd terminal of the 3 pin connector of ABS actuator (chassis harness side).
   Standard: Less than 5 Ω
   
   
   　

Abnormality of the wire harness.

Normal.

1. Confirm the DTC C1246 is inactive

   • Start the engine and let it idling condition.
   • Verify the DTC C1246 is inactive.

   

2. DTC Clear

   • Clear the DTC with Hino DX
   • Confirm the same DTC is not reoccurred

   

C1246 is reoccur: Return to first process Other DTC appear: Refer to concerned Trouble shooting

Complete