Yale 522660-1 – Engine ECU: Long Term Closed Loop Correction Bank 1 Greater Than NOR 30% (or 35%) (Lean Engine Operation)

This code indicates that the engine is running in a lean condition (too much air, not enough fuel). The engine's computer has maxed out its long-term fuel trim adjustments trying to add more fuel to compensate for the lean mixture, but the condition persists.

• Yale and Hyster Forklifts
• Yale and Hyster forklifts (2005 and newer)
• GLC030
• GLP050VX
• GLP060VX
• GLC080VX
• S50FT

1. 1

   Perform a hard reset by turning the forklift's power OFF for at least 30 seconds, then back ON. Operate the machine to see if the DTC reoccurs.

2. 2

   Visually inspect all connectors and wiring associated with the O2 sensor and fuel system for damaged wires, loose connections, or corrosion.

3. 3

   Inspect the fuel system for issues causing lean operation, such as bad fuel, tar buildup, a clogged fuel filter, or an incorrectly seated coupling to the fuel tank.

4. 4

   Check vacuum hoses routing to the bottom of the manifold and the pipe to the converter for leaks or disconnections.

1. 1

   Resolve Fuel Delivery Issues

   If tar or bad fuel is found, drain and clean the fuel system. Replace the fuel filter. Ensure the fuel tank coupling is seated perfectly.

2. 2

   Repair Wiring

   If the visual inspection revealed damaged wiring or connectors leading to the Engine ECU or O2 sensor, repair or replace the affected harness sections.

3. 3

   Replace the Oxygen Sensor

   If fuel delivery and wiring are confirmed good, the lean reading is likely due to a sensor failure (Heated Oxygen Sensor circuit signal outside of acceptable limits). Replace the O2 sensor.

4. 4

   Controller Replacement

   If all sensors, wiring, and fuel systems are functioning perfectly, a functional failure in the controller is possible. Replace the Engine ECU as a last resort.