Below is the service manual for the fault code you are having. Follow the troubleshooting guide and hopefully it will resolve your issue.

Heated Oxygen (O2) Sensor Circuit Signal Outside Of Acceptable Limits
CODES
DTC 522655-0 - Short Term Closed Loop Correction Bank 1 Less Than NOR -40% (Rich Engine Operation)
DTC 522655-1 - Short Term Closed Loop Correction Bank 1 Greater Than NOR 40% (Lean Engine Operation)
DTC 522660-0 - Long Term Closed Loop Correction Bank 1 Less Than NOR -35% (Rich Engine Operation)
DTC 522660-1 - Long Term Closed Loop Correction Bank 1 Greater Than NOR 35% (Lean Engine Operation)
POSSIBLE CAUSE
A. PROBLEMS THAT MAY CAUSE LEAN ENGINE OPERATION
B. PROBLEMS THAT MAY CAUSE RICH ENGINE OPERATION
C. SENSOR FAILURE
D. FUNCTIONAL FAILURE IN CONTROLLER
NOTE
Please refer to the end of this procedure for supporting diagrams.
COMPONENT OPERATIONAL CHECK
PROCEDURE OR ACTION:
1. Turn power to OFF for no less than 30 seconds, and then to ON to clear displayed DTC.
Does reported DTC reoccur?
YES: Go to Step 2.
NO: Problem not verified. Resume operation.
2. Conduct a quick visual inspection of all connectors/wiring associated with the displayed fault code.
Are any faults detected/observed?
YES:
* If DTC 522655-1 or 522660-1 occurs, go to Cause A.
* If DTC 522655-0 or 522660-0 occurs, go to Cause B.
Repair/replace connector or wiring associated with faults found. Refer to the appropriate Electrical System
SRM.
NO: Go to Cause A.
Diagnostic Trouble Codes Electrical System
Check the Service Manual section in Hypass Online for possible updates and check pertinent Grams
9030-20-492 Confidential/Proprietary - Do Not Copy or Duplicate
Heated Oxygen (O2) Sensor Circuit Signal Outside Of Acceptable Limits (Cont)
CAUSE A - PROBLEMS THAT MAY CAUSE LEAN ENGINE OPERATION
PROCEDURE OR ACTION:
NOTE: The following procedure does not specifically address the troubleshooting of the oxygen (O2
) sensor circuit but provides information relating to symptoms and other DTCs that need to be examined or resolved that may
cause this DTC to be displayed.
1. Common problems that may cause lean codes:
* Contaminated/clogged trim fuel injector's filter and/or LPG regulator's filter
* Contaminated/clogged trim fuel injector
* Faulty trim fuel injector or wiring
* Contaminated LPG fuel
* Low primary LPG fuel pressure (for trim fuel injector)
* Low secondary LPG fuel pressure (for carburetor)
* Clogged fuel hoses
* Contaminated/dirty carburetor
* Faulty fuel shutoff solenoids
* Engine overheating
* Exhaust leaks prior to or near oxygen (O2
) sensor
* Manifold vacuum leaks
* Improper ECU grounds on engine block
* Faulty ECU injector driver 2
2. If DTC continues to be displayed after examining/correcting the above, go to Cause C.
Electrical System Diagnostic Trouble Codes
Check the Service Manual section in Hypass Online for possible updates and check pertinent Grams
Confidential/Proprietary - Do Not Copy or Duplicate 9030-20-493
Heated Oxygen (O2) Sensor Circuit Signal Outside Of Acceptable Limits (Cont)
CAUSE B - PROBLEMS THAT MAY CAUSE RICH ENGINE OPERATION
PROCEDURE OR ACTION:
1. Common problems that may cause rich codes:
* Clogged/dirty air filter
* Fuel quality (Very high butane content)
* Operation at high altitudes
* High primary fuel pressure (for trim fuel injector)
* Faulty trim fuel injector or wiring
* Faulty LPG carburetor (power valve stuck open)
* Faulty LPG regulator
* Manifold vacuum leaks
* Improper ECU grounds on engine block
* Faulty ECU injector driver 2
2. If DTC continues to be displayed after examining/correcting the above, go to Cause C.
CAUSE C - SENSOR FAILURE
PROCEDURE OR ACTION:
1. Ensure truck power is OFF.
NOTE: Do not discard original sensor after removal.
2. Replace sensor.
3. Ensure that all connections are completely inserted.
4. Turn truck power ON.
Does reported DTC reoccur?
YES: Reinstall original sensor and go to Cause D. Refer to the appropriate Electrical System SRM.
NO: Problem has been corrected. Resume operation. Discard faulty sensor.
Diagnostic Trouble Codes Electrical System
Check the Service Manual section in Hypass Online for possible updates and check pertinent Grams
9030-20-494 Confidential/Proprietary - Do Not Copy or Duplicate
Heated Oxygen (O2) Sensor Circuit Signal Outside Of Acceptable Limits (Cont)
CAUSE D - FUNCTIONAL FAILURE IN CONTROLLER
PROCEDURE OR ACTION:
1. Ensure all previous procedures have been completed.
2. Ensure truck power is OFF.
3. Ensure that all connections to the controller are completely inserted.
4. Ensure truck power is OFF for no less than 30 seconds, and then to ON to clear displayed DTC.
Does reported DTC reoccur?
YES: Go to Step 5.
NO: Problem corrected. Resume operation.
5. At the DSC, press ENTER to access Main Menu.
6. Scroll to VIEW VERSIONS, press ENTER.
7. Scroll to TRUCK SERIAL NUMBER, press ENTER.
8. View the TRUCK SERIAL NUMBER on the display.
Does the truck serial number on display match serial number on truck nameplate (VSM Only)?
YES: Go to Step 9.
NO: Controller has been substituted from another truck. Replace VSM with VSM that has the correct truck
serial number or obtain new VSM with correct Serial number/ CDF. Refer to the appropriate Electrical System SRM.
9. Resident Service Approval Required prior to VSM replacement for Trucks under warranty. Make sure
to indicate the DTC code(s) on the warranty claim and include an accurate problem description leading to the
controller replacement.
10. For other controllers, Replace indicated controller. (ECU-ECM/GCU/TCU). Refer to the appropriate Electrical
System and Engine Fuel System SRM for all controllers.
11. Reinstall all removed components and ensure that all connectors are completely inserted.
NOTE: For Post 2007 Engine Connectors Interface, see Post 2007 Engine Connections.
12. Repeat Component Operational Check.
END POSSIBLE CAUSES