MALFUNCTION OF BOOST PRESSURE SENSOR [LO]
(DTC CODE P0237 / DIAGNOSIS MONITOR CODE 25)

1. Set the starter key to the "LOCK" position and disconnect the boost pressure sensor connector.
2. Measure resistance between the 2nd and 3rd terminals of the boost pressure sensor connector (component side).

   
   

   
   

   Standard value: 2-15 kΩ

    

3. Measure resistance between the 1st and 2nd terminals of the boost pressure sensor co nnector (component side).

   
   

   Standard value: 2-15 kΩ

   

   If it is difficult to troubleshoot the connector itself, go to [4] Measuring resistance between terminals.

    

NO Fault in boost pressure sensor	YES Proceed to[2] Measuring resistance between sensor terminals

1. Measure resistance between the 1st and 2nd terminals of the boost pressure sensor connector (vehicle harness side).

   
   

   Standard value: 209-231 kΩ

 

NO Go to [4] Measuring resistance between terminals.	YES Proceed to [3] Measuring voltage between sensor terminals

1. Turn the starter key "ON" and measure voltage between the 3rd and 1st terminals of the boost pressure sensor connector (vehicle harness side).

   

   Standard value: 4.5-5.5 V

 

NO Go to [4] Measuring resistance between terminals.	YES Disconnection of the harness

1. Set the starter key to the "LOCK" position and connect the signal check harness.
2. Disconnect the signal check harness connectors from the ECU and measure resistance between the terminals V81 and V83.

   
   

   

   ECU terminal No.	Description of terminal
   V81	Boost pressure sensor
   V83	+B

   Standard value: 2-15 kΩ

    

3. Measure resistance between the terminals V82 and V83.

   

   ECU terminal No.	Description of terminal
   V82	GND
   V83	+B

   Standard value: 2-15 kΩ

    

4. Measure resistance between the terminals V81 and V82.

   

   ECU terminal No.	Description of terminal
   V81	Boost pressure sensor
   V82	GND

   Standard value: ∞ Ω

NO Faulty harness or fault in boost pressure sensor	YES Proceed to[5] Measuring voltage between terminals

1. Connect the signal check harness connectors to the ECU.
2. Disconnect the signal check harness connectors from the vehicle harness.
3. Turn the starter key "ON" and measure voltage between the terminals V83 and V82.



 

ECU terminal No.	Description of terminal
V82	GND
V83	+B

Standard value: 4.5-5.5 V

 

NO Fault in engine ECU	YES Proceed to [6] Measuring resistance between terminals

1. Set the starter key to the "LOCK" position and measure resistance between the terminals V81 and V82.

   

   ECU terminal No.	Description of terminal
   V81	Boost pressure sensor
   V82	GND

   Standard value: 209-231 kΩ

 

NO Fault in engine ECU	YES Disconnection of the harness

1. Confirm the DTC P0237 is inactive

   • Start the engine and let it idling condition.
   • Verify the DTC P0237 is inactive.

   

2. DTC Clear

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

   

P0237 is reoccur: Return to first process Other DTC appear: Refer to concerned Trouble shooting

Complete