C3.4B Engines Caterpillar


DEF Pump Pressure Sensor - Test

Usage:

CCS7 4B2
This procedure covers the following diagnostic codes.

Table 1
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. 


Illustration 1g03726274
Schematic diagram for the DEF pump pressure sensor


Illustration 2g03726284
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


Illustration 3g03720379
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)

Table 2
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 30 N (6.7 lb) pull test on each of the wires in the ECM connector and the connector for the DEF pump.

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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