Hino P1428 Fault Code: Differential Pressure Sensor – Out Of Range (Out Of Range High)

Technical Description

It detects a difference between pressure at the inlet of the muffler and atmospheric pressure and monitors any failure or malfunction of the DPR

Description Of Malfunction

• Exhaust pressure cannot be correctly recognized
• Possible DPR differential pressure sensor failure or harness +B short

Dtc Set Condition

Check Condition:

• Starter switch ON
• Battery voltage is in the range of 10V to 16V

The conditions described above remain for 5 seconds or longer

Judgment Criteria:

Output of the sensor remains greater than 4.46 V (95.1 kPa {13.8 psi}) for 3 seconds

Reset Condition

Immediately after normal operation is restored

Indication, Warning Or System Control Regulation When The Dtc Is Set

• MIL: ON
• SVS light: OFF

Pre-Inspection Work

Check that the battery voltage is in the normal range

After-Inspection Work

• Clear all past DTCs
• Check if the DTC is stored after test drive

Possible Causes

• Abnormal resistance of sensor
• Harness disconnection or short-circuit
• Looseness or poor contact of connector
• Malfunction of engine ECU sensor power supply or internal circuit

Inspection Procedure

Troubleshooting Steps

Step 1: Inspect the differential pressure sensor connector

Check the connection of the differential pressure sensor connector (Looseness and poor contact)

Were any failures found?

Step 2: Inspect the differential pressure sensor.

1. Check the installation of the differential pressure sensor
2. Make sure there is no dirt or damage to the differential pressure sensor

Were any failures found?

Step 3: Inspect the differential pressure sensor power supply.

1. Set the starter switch to the “ON” position
2. Use the electrical tester to measure the voltage between the terminals of the differential pressure sensor vehicle-side connector.

Do the measurements meet the standard value?

Step 4: Inspect the differential pressure sensor unit

1. Set the starter switch to the “LOCK” position
2. Disconnect the differential pressure sensor connector
3. Use the electrical tester to measure the resistance between the terminals of the differential pressure sensor

Do the measurements meet the standard value?

Step 5: Inspect for short-circuit of the differential pressure sensor harness

1. Set the starter switch to the “LOCK” position
2. Connect the signal check harness to the engine ECU vehicle-side harness. (Do not connect the harness to the ECU)
3. Use the electrical tester to measure the resistance between the terminals of the engine ECU (signal check harness) and ground

Do the measurements meet the standard value?

Step 6: Inspect disconnection of the differential pressure sensor harness

1. Connect the differential pressure sensor connector
2. Use the electrical tester to measure the resistance between the terminals of the engine ECU (signal check harness)

Do the measurements meet the standard value?

Step 7: Check the DTC detected (Engine ECU) [Diagnostic Tool]

1. Perform engine warm-up. (Engine coolant temperature: 60°C {140°F} or more)
2. Stop the engine and set the starter switch to the “LOCK” position
3. Connect the vehicle to the diagnostic tool
4. Set the starter switch to the “ON” position
5. Select [Engine] and check if P1428 has been detected

Has DTC P1428 been detected?

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