Hino P2049 Fault Code: DEF Injector – Disconnection (Disconnection (High Side))

Technical Description

• DEF dosing valve is controlled by DCU.
• DEF dosing valve detects disconnection and short-circuit based on the circuit voltage and signals in DCU.

Description Of Malfunction

DEF injector failure is detected.

DTC Set Condition

DTC Detection Condition:

• Starter switch ON.
• DEF injector duty cycle > 0%

Judgment Criteria:

DEF dosing valve circuit voltage (High side): Below 2 V for more than 0.05 sec.

Reset Condition

After having restored to the normal conditions.

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

• MIL: ON
• SCR malfunction light: ON
• DEF injection is stopped.
• NOx reduction quantity monitoring is aborted.
• If malfunction does not improve within 500 miles: engine output is restricted.
• If malfunction does not improve within 2,000 miles: vehicle speed is restricted.

Symptoms On The Vehicle When The DTC Is Set

Symptoms on the Vehicle Due to Backup Control (Fail Safe Function):

• Exhaust gas purification function is declined.
• Engine output is insufficient (when malfunction does not improve within 500 miles).
• Vehicle does not speed up (when malfunction does not improve within 2,000 miles).

Pre – Inspection Work

Check if the battery voltage is in the normal range.

After – Inspection Work

• Clear all past DTCs.
• Reset “Urea SCR related memory”.
• Check if no DTC is stored after test drive.

Possible Causes

• Disconnection or short-circuit in sensor harness.
• Abnormal resistance of DEF injector.
• Malfunction in DEF injector.

Inspection Procedure

Troubleshooting Steps

Step 1) Inspect the DEF injector connector.

Check the connection of the DEF injector connector (Looseness and poor contact).

Was any failure found?

Step 2) Inspect the DEF injector unit.

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

Do the measurements meet the standard value?

Step 3) Inspect for short-circuit in the DEF injector harness.

1. Disconnect the DCU 86P connector.
2. Connect the signal check harness and use the electrical tester to measure the resistance between the terminals of the DCU 86P vehicle-side connector and the ground.

Do the measurements meet the standard value?

Step 4) Inspect disconnection of the DEF injector harness.

1. Connect the DEF injector connector.
2. Connect the signal check harness and use the electrical tester to measure the resistance between the terminals of the DCU 86P vehicle-side connector.

Do the measurements meet the standard value?

Step 5) DTC the DTC detected (DCU) [Diagnostic Tool].

1. Perform an engine warm-up. (Water temperature: 60oC {140oF} 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 [DCU] and check if P2049 has been detected.

Has DTC P2049 been detected?

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