MALFUNCTION OF EXHAUST CONTROL VALVE/SOLENOID VALVE SYSTEM [DISCONNECTION/GND SHORT-CIRCUIT]
(DTC CODE P1681 / DIAGNOSIS MONITOR CODE 57)

1. Set the starter key to the "LOCK" position and connect the signal check harness.
2. Turn the starter key "ON" and measure voltage between the terminals V4 and V5.
   

   

   ECU terminal No.	Description of terminal
   V4	Exhaust brake solenoid valve 1
   V5	Exhaust brake solenoid valve power supply

   Standard value: 19 V or more

NO Go to [2] Measuring resistance between the solenoid valve.	YES Fault in engine ECU and/or ECU connectors

1. Set the starter key to the "LOCK" position and disconnect the exhaust control valve/solenoid valve connector.
2. Measure resistance between the 1st and 2nd terminals of the exhaust control valve solenoid valve connector (component side).
   

   

   Standard value: 35-50 Ω

NO Fault in exhaust control valve/solenoid valve	YES Fault in harness, connector or actuator relay

1. Confirm the DTC P1681 is inactive

   • Start the engine and let it idling condition.
   • Verify the DTC P1681 is inactive.

   

2. DTC Clear

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

   

P1681 is reoccur: Return to first process Other DTC appear: Refer to concerned Trouble shooting

Complete