Eaton Fuller Advantage (2017) Fault Code: 52 PID: 59 SPN: FMI: 4 Gear Position Sensor: Voltage Below Normal or Shorted Low

Overview:
The Fuller Advantage X-Y Shifter is equipped with a Gear Position Sensor. The X-Y Gear Position Sensor reports fore-and-aft movement of the Shift Finger to the Transmission Electronic Control Unit (TECU) as a voltage signal. The X-Y Gear Position Sensor is connected to the TECU via the Transmission Harness. The TECU performs continuous diagnostics on the circuit to detect a shorted circuit, open circuit or incorrect position reading. Fault Code 52 is set when TECU has detected either an electrical failure of the X-Y Gear Position Sensor circuit or a mechanical failure within the X-Y Shifter.

Detection:
The TECU monitors both the 5-volt X-Y Gear Position Sensor supply and the return voltage signal from the X-Y Gear Position Sensor. If the system detects that either the supply voltage or return voltage is out of range, the fault code is set Active.

Conditions to Set Fault Code Active:
FMI 4 – Voltage Below Normal or Shorted Low: TECU detects the X-Y Gear Position Sensor supply voltage is below 4.75 volts for 1 second or longer.

Fallback:
All FMIs:
• “F” flashes in gear display.
• Service light flashes (if equipped).
• Transmission remains in current gear.
• Until the fault becomes Inactive, driver may have to shut off engine with transmission in gear

Conditions to Set Fault Code Inactive:
FMI 3, 4: Supply voltage stays within the 4.75–5.25-volt range for 1 second.

Possible Causes:
FMI 2, 4 or 7:
1) Transmission Harness
– Bent, spread, corroded or loose terminals
– Wiring shorted to ground, shorted to power or open
2) X-Y Shifter
– Bent, spread, corroded or loose terminals
– Wiring shorted to ground, shorted to power or open
– Gear Position Sensor damaged
3) TECU
– Internal failure