Yale 522655-0 – Engine ECU (Mazda Gas ECU or GM ECU): Short Term Closed Loop Correction Bank 1 Less Than NOR -35%

Rich Engine Operation condition. The oxygen (O2) sensor detects that the fuel ratio has too little air and too much fuel, meaning something in the fuel system is causing the air and fuel to mix incorrectly.

• Yale and Hyster Forklifts
• Yale VX series (GLC050VX, GLP030VX, GLP050VX, GLP060VX)
• Hyster FT series (Fortens 30-60FT, S60FT)

1. 1

   Clear the code by turning the power OFF for no less than 30 seconds, then turn it ON to check if the DTC reoccurs.

2. 2

   Conduct a visual inspection of all connectors and wiring associated with the O2 sensor and fuel system, looking for shorts to ground or battery.

3. 3

   Check for a dirty air filter, bad fuel, or thin air at high altitudes.

4. 4

   Inspect fuel delivery components for fuel injector issues, a dirty/clogged fuel filter, or a clogged fuel pump strainer (especially on dual-fuel models).

5. 5

   Check the vacuum system for any leaks.

6. 6

   Test LPG system components for a faulty LPG vaporizer (internal leaks), a faulty LPG regulator/EPR (Electronic Pressure Regulator), or a faulty LPG mixer.

7. 7

   Check the spark plugs to ensure they are in good shape and the gap is set correctly.

1. 1

   Repair wiring and connectors

   If the visual inspection reveals damaged wiring or connectors associated with the O2 sensor or fuel system, repair or replace them first.

2. 2

   Perform filter maintenance

   Replace the fuel filter and service the air filter if they are dirty.

3. 3

   Clean the mixer

   Clean out the air intake carburetor/mixer.

4. 4

   Replace the vaporizer

   If troubleshooting points to the LPG vaporizer leaking internally, replace the vaporizer assembly.

5. 5

   Rebuild or replace the EPR

   Replace the entire EPR (Electronic Pressure Regulator) assembly or rebuild it using a minor or major repair kit. Tech Note: When disassembling the EPR, be extremely careful with the plastic coolant fittings, as they are very brittle and break easily. Rebuilding the EPR involves small springs and O-rings, so it is recommended only for those experienced in fuel system repair.