57969A12 Mercruiser CYLINDER, BOOSTER - POWER STEERING

Table 1
Diagnostic Trouble Codes
J1939 Code Code Description Comments
4334-3 Aftertreatment #1 DEF #1 Pressure (absolute) : Voltage Above Normal There is excessive voltage on the signal wire between the Diesel Exhaust Fluid Controller (DCU) and the DEF pump or there is an open circuit on the supply, signal, or return wire.
The code is logged.
4334-4 Aftertreatment #1 DEF #1 Pressure (absolute) : Voltage Below Normal There is low voltage on the signal wire between the DCU and the DEF pump pressure sensor.
The code is logged.
Follow the troubleshooting procedure in order to identify the root cause of the problem. Note: 372-5260 Test Kit is required for completing this procedure.
Illustration 1 g03184659
Table 2
Troubleshooting Test Steps Values Results
1. Check for Opens in the Pump Electronic Tank Unit (PETU) Wiring Harness for the DEF Pump Pressure Sensor Circuit
A. Turn the keyswitch to the OFF position for 2 minutes. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the Diesel Exhaust Fluid Controller (DCU).
B. Disconnect the PETU wiring harness from the DEF pump and the DCU.
C. Connect the 398-5063 Break-out Connector to the DCU connector. Connect the 398-5056 Break-out Connector to the DEF pump connector.
The connectors must be used to prevent damage to the DCU and DEF pump connector.
D. Measure the resistance between terminal 2 (SUPPLY) on the DEF pump connector and terminal 19 (SUPPLY) on the 86 pin DCU connector.
E. Measure the resistance between terminal 3 (SIGNAL) on the DEF pump connector and terminal 17 (SIGNAL) on the 86 pin DCU connector.
F. Measure the resistance between terminal 4 (GROUND) on the DEF pump connector and terminal 18 (GROUND) on the 86 pin DCU connector.
Open circuit
Result: There was less than 10 Ohms of resistance on all of the DEF pump pressure circuit wires.
Proceed to Test Step 2.
Result: There was more than 10 Ohms of resistance on any one of the DEF pump pressure circuit wires.
There is an open in the harness. Repair the wiring or replace the harness.
Verify that the problem is resolved.
Proceed to Test Step 4.
2. Check for Short Circuits in the PETU Wiring Harness for the DEF Pump Pressure Sensor Circuit
A. Turn the keyswitch to the "OFF" position.
B. Disconnect the PETU wiring harness from the DEF pump and the DCU.
C. Connect the 398-5056 Break-out Connector to the DEF pump connector.
The connector must be used to prevent damage to the DEF pump connector.
D. Measure the resistance between terminal 2 (SUPPLY) on the DEF pump connector and a known good chassis ground.
E. Measure the resistance between terminal 3 (SIGNAL) on the DEF pump connector and a known good chassis ground.
F. Measure the resistance between terminal 4 (GROUND) on the DEF pump connector and a known good chassis ground.
Short circuit
Result: There was more than 100 K Ohms of resistance between the connector terminal and ground on all of the DEF pump pressure circuit wires.
Proceed to Test Step 3.
Result: There was less than 100 K Ohms of resistance between the connector terminal and ground on any one of the DEF pump pressure circuit wires.
There is a short circuit in the harness. Repair the wiring or replace the harness.
Verify that the problem is resolved.
Proceed to Test Step 4.
3. Check for Short Circuits in the PETU Wiring Harness for the DEF Pump Pressure Sensor Circuit
A. Turn the keyswitch to the "OFF" position.
B. Disconnect the PETU wiring harness from the DEF pump and the DCU.
C. Connect the 398-5063 Break-out Connector to the DCU connector.
The 398-5063 Break-out Connector must be used to prevent damage to the DCU connector.
D. Measure the resistance between terminal 19 (SUPPLY) of the DCU connector and all other pins in the 86 pin DCU harness connector.
E. Measure the resistance between terminal 17 (SIGNAL) of the DCU connector and all other pins in the 86 pin DCU harness connector.
F. Measure the resistance between terminal 18 (GROUND) of the DCU connector and all other pins in the 86 pin DCU harness connector.
Short circuit
Result: There was more than 100 K Ohms of resistance on all of the DEF pump pressure circuit wires.
A failed DEF pump has been detected. Replace the DEF pump.
Proceed to Test Step 4.
Result: There was less than 100 K Ohms of resistance on any one of the DEF pump pressure circuit wires.
There is a short circuit in the harness. Repair the wiring or replace the harness.
Verify that the problem is resolved.
Proceed to Test Step 4.
4. Perform a DEF Dosing System Verification Test
A. Turn the keyswitch to the "ON" position. Do not start the engine.
B. Connect to the "Diesel Exhaust Fluid Controller #1 ECM" using Cat ET.
C. Perform the "DEF Dosing System Verification Test" .
Diagnostic codes
Result: The code did not return.
Return the unit to service.
Complete the procedure in the order in which the steps are listed.