Hino P204D Fault Code: DEF pressure sensor – out of range (out of range high)
Technical description
− The pressure sensor in the DEF pump is used to confirm the pressure in the DEF pump.
− A short-circuit or disconnection in the DEF pump pressure sensor is detected with the DCU.
Description of malfunction
Failure of the pressure sensor in the DEF pump is detected.
DTC Set condition
DTC Detection Condition:
Starter switch ON.
Judgment Criteria:
DEF pump pressure sensor circuit voltage > 4.75 V for more than 0.4 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 2000 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):
− NOx reduction function is prevented.
− Engine output is insufficient (when malfunction does not improve within 500 miles)
− Vehicle does not speed up (when malfunction does not improve within 2000 miles)
Pre-inspection work
Check that the battery voltage is in the normal range.
After-inspection work
− Clear all past DTCs.
− Reset “Ure SCR related memory” by the diagnostic tool “Data monitor and Activation test”
− Check that no DTC is detected after test drive.
Possible causes
– Harness disconnection or short-circuit
− Malfunction of DEF pump (pressure sensor)
+ Internal circuit disconnection or short-circuit
+ Abnormal output voltage.
Inspection procedure
Troubleshooting steps
Step 1) Inspect the DEF pump connector.
Check the connection of the DEF pump connector. (Looseness and poor contact).
Was any failure found ?
| Yes – Connect securely, repair if needed. Clear all past DTCs. Reset “Urea SCR related memory” by the diagnostic tool “Data monitor and Activation test”. Check if no DTC is stored after test drive. | No – Go to Step 2. |
Step 2) Inspect the DEF pump (pressure sensor) unit.
- Set the starter switch to the “LOCK” position.
- Disconnect the DEF pump connector.
- Use the electrical tester to measure the resistance between the terminals of the DEF pump pressure sensor.
| MEASUREMENT CONDITIONS | TESTER CONNECTIONS | STANDARD VALUES |
| Starter switch: LOCK | DEF pump connector
(1) PSR+ – PSR- (2) PSR+ – PSRS (3) PSR- – PSRS |
(1) 185 – 215 kΩ(2) 148 – 172 kΩ
(3) 333 – 387 kΩ |
Do the measurements meet the standard value ?
| Yes – Go to Step 3. | No – Replace the DEF pump. Clear all past DTCs. Reset “Urea SCR related memory” by the diagnostic tool “Data monitor and Activation test”. Check if no DTC is stored after test drive. |
Step 3) Check for short-circuit in wire harness of DEF pump (pressure sensor).
- Disconnect the DCU 86P connector.
- 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.
| MEASUREMENT CONDITIONS | TESTER CONNECTIONS | STANDARD VALUES |
| Starter switch: LOCK | DCU 86P vehicle-side connector PSR+ – Ground
PSRS – Ground PSR- – Ground |
∞ Ω |
Do the measurements meet the standard value ?
| Yes – Go to Step 4. | No – Repair or replace the harness. Clear all past DTCs. Reset “Urea SCR related memory” by the diagnostic tool “Data monitor and Activation test”. Check if no DTC is stored after test drive. |
Step 4) Check for disconnection in wire harness of DEF pump (pressure sensor).
- Connect the DEF pump connector.
- Connect the signal check harness and use the electrical tester to measure the resistance between the terminals of the DCU 86P vehicle-side connector.
| MEASUREMENT CONDITIONS | TESTER CONNECTIONS | STANDARD VALUES |
| Starter switch: LOCK | DCU 86P vehicle-side connector (1) PSR+ – PSR-
(2) PSR+ – PSRS (3) PSR- – PSRS |
(1) 185 – 215 kΩ(2) 148 – 172 kΩ
(3) 333 – 387 kΩ |
Do the measurements meet the standard value ?
| Yes – Go to Step 5. | No – Repair or replace the harness. Clear all past DTCs. Reset “Urea SCR related memory” by the diagnostic tool “Data monitor and Activation test”. Check if no DTC is stored after test drive. |
Step 5) Check the DTC detected (DCU) [Diagnostic Tool].
- Set the starter switch to the “LOCK” position.
- Connect the vehicle to the diagnostic tool.
- Set the starter switch to the “ON” position.
- Select [DCU] and check if P204D has been detected.
Has P204D been detected ?
| Yes – Replace the DCU. Clear all past DTCs. Reset “Urea SCR related memory” by the diagnostic tool “Data monitor and Activation test”. Check if no DTC is stored after test drive.. | No – Procedure completed. Clear all past DTCs. Reset “Urea SCR related memory” by the diagnostic tool “Data monitor and Activation test”. Check if no DTC is stored after test drive. |
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