DEF Pump Pressure Sensor - Test
This procedure covers the following diagnostic codes.
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| Diagnostic Trouble Codes | ||
|---|---|---|
| J1939 Code | Code Description | Comments |
| 4334-3 | Aftertreatment #1 SCR Dosing Reagent Absolute Pressure : Voltage Above Normal | The Electronic Control Module (ECM) detects that the signal from the Diesel Exhaust Fluid (DEF) pump pressure sensor is greater than 4.75 V for at least 1 second.
The battery voltage is at least 10 V. The warning lamp will come on. |
| 4334-4 | Aftertreatment #1 SCR Dosing Reagent Absolute Pressure : Voltage Below Normal | The ECM detects that the signal from the DEF pump pressure sensor is less than 0.25 V for at least 1 second.
The battery voltage is at least 10 V. The warning lamp will come on. |
| Follow the troubleshooting procedure in order to identify the root cause of the problem. | ||
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| Illustration 1 | g03726274 |
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Schematic diagram for the DEF pump pressure sensor | |
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| Illustration 2 | g03726284 |
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View of the pin locations on the P2 ECM connector for the DEF pump pressure sensor (5) DEF pump pressure sensor ground (7) DEF pump pressure sensor supply (+5 V) (56) DEF pump pressure sensor signal | |
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| Illustration 3 | g03720379 |
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Pin locations on the DEF pump module connector (8) DEF pump pressure sensor ground (9) DEF pump pressure sensor signal (10) DEF pump pressure sensor supply (+5 V) | |
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| Troubleshooting Test Steps | Values | Results |
|---|---|---|
1. Inspect Electrical Connectors and Wiring A. Inspect the P2/J2 ECM connector. B. Inspect the connector for the DEF pump. C. Perform a D. Check all of the wiring associated with the DEF pump for abrasions and pinch points. |
Damaged wire or connector |
Result: A damaged wire or damaged connector was not found. Proceed to Test Step 2. Result: A damaged wire or damaged connector was found. Repair: Repair the damaged wire or the damaged connector. Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault. |
2. Check for Active Diagnostic Codes A. Establish communication between the electronic service tool and the ECM. Refer to Troubleshooting, "Electronic Service Tools" B. Check for active or logged codes. |
Diagnostic Trouble Codes |
Result: There is an active or logged , 4334-3 or 4334-4 diagnostic code. Proceed to Test Step 3. |
3. Check the Sensor Supply and Ground Wiring A. Turn the keyswitch to the OFF position for 2 minutes. B. Disconnect the DEF pump connector. C. Turn the keyswitch to the OFF position. D. Use a multimeter to measure the voltage between terminal 8 and terminal 10 on the harness connector for the DEF pump. E. Turn the keyswitch to the OFF position. |
4.9 V to 5.1 V |
Result: The measured voltage is not within the expected range. The fault is in the wiring between the DEF pump and the P2 ECM connector. Repair: Replace the faulty wiring. Proceed to Test Step 5. Result: The measured voltage is within the expected range. Proceed to Test Step 4. |
4. Check the Voltage on the Sensor Signal Wiring A. Turn the keyswitch to the OFF position for 2 minutes. B. Disconnect the connector for the DEF pump. C. Turn the keyswitch to the ON position. D. Use a multimeter to measure the voltage between terminal 8 and terminal 9 on the harness connector for the DEF pump. E. Turn the keyswitch to the OFF position. |
4.9 V to 5.1 V |
Result: The measured voltage is not within the expected range. The fault is in the wiring between the DEF pump and the P2 ECM connector. Repair: Replace the faulty wiring. Proceed to Test Step 5. Result: The measured voltage is within the expected range. Repair: Install a replacement DEF pump module. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Proceed to Test Step 5. |
5. Perform a DEF Dosing System Verification Test A. Start the engine. B. Use the electronic service tool to perform the "DEF Dosing System Verification Test". |
Diagnostic codes |
Result: The diagnostic code did not return. Return the unit to service. Result: The diagnostic code returned. Contact the Dealer Solution Network (DSN). |
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