803666 3 Mercury COVER, Exhaust

Table 1
Diagnostic Codes Table
CDL Code and Description Conditions which Generate this Code System Response
3094-5
Aftertreatment #1 SCR Dosing Air Assist Signal:Current Below Normal The Electronic Control Module (ECM) detects an open in the circuit for the solenoid valve. The code is logged.
3094-6
Aftertreatment #1 SCR Dosing Air Assist Signal:Current Above Normal The ECM detects a short in the circuit for the solenoid valve. The code is logged.
3120-5
Aftertreatment #1 SCR Catalyst Reagent Return Signal:Current Below Normal The Electronic Control Module (ECM) detects an open in the circuit for the solenoid valve. The code is logged.
3120-6
Aftertreatment #1 SCR Catalyst Reagent Return Signal:Current Above Normal The ECM detects a short in the circuit for the solenoid valve. The code is logged.
Illustration 1 g03546576
Schematic for the solenoid valves
In order to aid troubleshooting, overrides are provided via Cat ET.Overrides allow the technician to turn the circuit on and off at will.Refer to table 2 for the appropriate override for the code.
Table 2
Component Override
3094-5
Aftertreatment #1 SCR Dosing Air Assist Signal:Current Below Normal Aftertreatment #1 SCR Dosing Air Assist Valve Command Override
3094-6
Aftertreatment #1 SCR Dosing Air Assist Signal:Current Above Normal
3120-5
Aftertreatment #1 SCR Catalyst Reagent Return Signal:Current Below Normal Aftertreatment #1 SCR Catalyst Reagent Return Valve Override
3120-6
Aftertreatment #1 SCR Catalyst Reagent Return Signal:Current Above Normal Note: Some solenoid valve assemblies have a solenoid that can be serviced separately. The solenoid may be called out as a coil in the parts book.Test Step 1. Determine the Diagnostic Code
Establish communication between Cat ET and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
Download the "Warranty Report" from the ECM before performing any troubleshooting or clearing diagnostic trouble codes. Wait at least 30 seconds in order for the diagnostic codes to become active.
Look for these active codes or logged codes:
-5
-6Results:
A -5 diagnostic code is active. - Proceed to Test Step 2.
A -6 diagnostic code is active. - Proceed to Test Step 3. Test Step 2. Check the Wiring for an Open Circuit
Verify that the harness connectors are free of debris, free of corrosion and securely connected.
Disconnect the harness from the solenoid valve.
Connect a jumper wire between the terminals of the harness connector for the suspect solenoid valve. The solenoid valve is replaced with a short circuit.
Clear the -5 code.
Activate the override for the suspect circuit. Refer to table 2 for the appropriate override for the code. Results:
A -5 code became active during the override. - The ECM did not detect the jumper wire. There is an open circuit in the wiring between the solenoid valve and the ECM connector. There may be a problem with a connector.Repair: Repair the appropriate harness wiring or replace the appropriate harness.Verify that the problem is resolved.STOP
A -6 code became active during the override. The ECM detected the jumper wire. There is a problem with the solenoid. - Repair: Replace the solenoid valve.Verify that the problem is resolved.STOPTest Step 3. Check the Wiring for a Short Circuit
Verify that the harness connectors are free of debris, free of corrosion and securely connected.
Disconnect the harness from the solenoid valve.
Clear the -6 code.
Activate the override for the suspect circuit. Refer to table 2 for the appropriate override for the code. Results:
A -6 code became active during the override. - The ECM did not detect the open circuit. There is a short circuit in the wiring between the solenoid valve and the ECM connector. There may be a problem with a connector.Repair: Repair the appropriate harness wiring or replace the appropriate harness. Verify that the problem is resolved.STOP
A -5 code became active during the override. - The ECM detected the open circuit. The wiring is OK. The solenoid has a short circuit.Repair: Replace the solenoid valve.Verify that the problem is resolved.STOP