C1266 ABNORMALITY OF EXHAUST BRAKE CUT RELAY

1. Set the starter switch to "LOCK", disconnect the 24 pin connector of ECU and exhaust brake cut relay of the relay block.
   
2. Check the continuity between 10th terminal of the 24 pin connector of ECU (chassis harness side) and 5th terminal of the relay connector (chassis harness side).
   Standard: Continuity
   
   
   　

Disconnection of the wire harness.

[1]-3

3. Disconnect the 28 pin connector of ECU.
4. Check the continuity between 18th terminal of the 28 pin connector of ECU (chassis harness side) and 3rd terminal of the relay connector (socket side).
   Standard: Continuity
   
   

Ground short of the wire harness.

[2] EXHAUST BRAKE CUT RELAY CHECK

1. When 24V is applied and is not applied between 2nd and 1st terminals
   of exhaust brake cut relay, check the continuity between its 4th and 3rd terminals.
   
   Connect (+) side with 1st terminal of relay.
   　

   2nd and 1st terminals	4th and 3rd terminals
   24V is conducted	No continuity
   Not conducted	Continuity

Abnormality of the exhaust brake cut relay.

Normal.

1. Confirm the DTC C1266 is inactive

   • Start the engine and let it idling condition.
   • Verify the DTC C1266 is inactive.

   

2. DTC Clear

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

   

C1266 is reoccur: Return to first process Other DTC appear: Refer to concerned Trouble shooting

Complete