Yale 522603-4 – Engine Control Module (ECM) or Vehicle System Manager (VSM): Fuel Temp (LPG) Sensor OORL

The voltage signal from the LPG fuel temperature sensor has dropped below the minimum acceptable threshold.

• Yale and Hyster Forklifts
• 2005 and newer Yale and Hyster forklifts
• Yale VX series (GLC030VX, GLP040-070VX)
• Hyster FT series (H80FT, S40-70FT)
• Machines utilizing GM 2.4L, Mazda 2.0L/2.2L, and Yanmar LPG engines equipped with Impco Spectrum fuel systems

1. 1

   Inspect the fuel temperature sensor, its connector, and the wiring harness for physical damage, corrosion, or loose connections

2. 2

   Use a multimeter to test the sensor signal wire for an open circuit or a short to ground

3. 3

   Measure the resistance and voltage of the fuel temperature sensor to determine if it is out of specification

4. 4

   Use diagnostic equipment or a handset to test the sensor signal voltage under live operating conditions

5. 5

   Verify the controller (ECM/VSM) sensor input voltages to rule out a controller failure

1. 1

   Disconnect Power

   Disconnect the battery to ensure safety before performing electrical repairs.

2. 2

   Repair Wiring

   Repair or replace any damaged sections of the wiring harness, focusing specifically on shorts to ground or open wires.

3. 3

   Clean Connectors

   Clean any corroded connector terminals or replace the connector pigtail if it is heavily damaged.

4. 4

   Replace Sensor

   If the wiring is intact but the sensor tested out of spec, remove and replace the LPG fuel temperature sensor.

5. 5

   Clear Codes

   Reconnect the battery and clear the fault codes using the diagnostic handset or software.

6. 6

   Verify Repair

   Run the forklift and monitor the live sensor data to verify the repair.

7. 7

   Controller Replacement

   If the code immediately returns and the sensor and wiring are confirmed 100% good, replace the engine control module (ECM) or VSM, as the internal input circuitry has failed.