803528 Mercury BRACKET

Table 1
J1939 Code and Description CDL Code and Description Comments
6797-7
Aftertreatment #1 SCR Intake Absolute Pressure : Not Responding Properly 4054–7
Aftertreatment #1 DEF Doser #1 Pressure Not Responding To Command The Selective Catalyst Reduction (SCR) Catalyst Intake Pressure is below the normal operating range for Aftertreatment bank #1.
6797-17
Aftertreatment #1 SCR Intake Absolute Pressure : Low - least severe (1) 1637–1
Low Aftertreatment #1 SCR Catalyst Intake Pressure The SCR Catalyst Intake Pressure is below the normal operating range for Aftertreatment bank #1.
6797-18
Aftertreatment #1 SCR Intake Absolute Pressure : Low - moderate severity (2) 1637-2
Low Aftertreatment #1 SCR Catalyst Intake Pressure (2) The SCR catalyst intake pressure is below the normal operating range for aftertreatment bank #1.
6798-7
Aftertreatment #2 SCR Intake Absolute Pressure : Not Responding Properly 4055–7
Aftertreatment #2 DEF Doser #1 Pressure Not Responding To Command The Selective Catalyst Reduction (SCR) Catalyst Intake Pressure is below the normal operating range for Aftertreatment bank #2.
6798-17
Aftertreatment #2 SCR Intake Absolute Pressure : Low - least severe (1) 1638–1
Low Aftertreatment #2 SCR Catalyst Intake Pressure The SCR Catalyst Intake Pressure is below the normal operating range for Aftertreatment bank #2. Probable Causes
Codes
Sensor
Debris
Supply Voltage
LeaksRecommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Turn the keyswitch to ON.
B. Connect Cat® Electronic Technician (ET) to the service tool connector.
C. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
2. Verify that the Selective Catalyst Reduction (SCR) Intake Pressure Sensor is Installed
A. Turn the keyswitch to OFF.
B. Visually inspect the affected exhaust system bank to ensure that the SCR intake pressure sensor has not been tampered with or removed.
Sensor
Result: The SCR intake pressure sensor is installed in the exhaust system.
Proceed to Test Step 3.
Result: The SCR intake pressure sensor is not installed in the exhaust system.
Repair: Install the SCR intake pressure sensor into the exhaust system.
If the problem is not resolved, proceed to Test Step 3.
3. Check for Debris
A. Turn the keyswitch to OFF.
B. Check the SCR catalyst inlet pressure sensor on the affected exhaust bank for debris.
C. Check the sensor measurement port for blockage by debris.
Debris
Result: The sensor measurement port is OK.
Proceed to Test Step 4.
Result: The sensor measurement port is NOT OK.
Repair: Clear the debris from the measurement port and replace the suspect sensor.
Proceed to Test Step 6.
4. Check the Supply Voltage
A. Turn the keyswitch to OFF.
B. Disconnect the affected SCR catalyst inlet pressure sensor from the wiring harness connector.
C. Measure the voltage between pin 1 and pin 2 at the wiring harness connectors.
5 VDC
Result: The voltage was OK.
Proceed to Test Step 5.
Result: The voltage was NOT OK.
Repair: There is a problem with the supply voltage to the sensor. Determine the cause of the supply voltage issue. Refer to the Troubleshooting, Sensor Supply - Test for additional information.
If the problem is not resolved, proceed to Test Step 5.
5. Inspect for Exhaust Leaks
A. Inspect the piping between the turbine outlet and the affected SCR catalyst inlet for signs of leaks.
Leaks
Result: An exhaust leak was not found.
Repair: A failed SCR catalyst inlet pressure sensor has been detected. Replace the SCR catalyst inlet pressure sensor.
Proceed to Test Step 6.
Result: An exhaust leak was found.
Repair: Repair or replace damaged exhaust component.
If the problem is not resolved, proceed to Test Step 6.
6. Perform an "Aftertreatment System Functional Test"
A. Turn the keyswitch to OFF.
B. Connect Cat ET.
C. Perform an "Aftertreatment System Functional Test".
"Aftertreatment System Functional Test"
Result: The Aftertreatment System Functional Test passed successfully.
Return to service.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).