Eaton Gen 2 (AutoShift) Fault Code: 31 PID: SID 218 FMI: 4 Momentary Ignition Interrupt Relay

Overview:
Fault Code 31indicates an electrical failure of the Momentary Engine Ignition Interrupt Relay (MEIIR) circuit.

Detection:
The fault is detected during power up. The Shift Controller checks the MEIIR circuit every time the system is powered up. If the electrical characteristics of the circuit are incorrect, the fault code is set.

Fallback:
There is no fallback associated with this failure; however, if the engine speed flares uncontrollably while the transmission is in a gear, the transmission may not be able to achieve neutral if it is selected due to a torque lock condition.

Possible Causes:
1) OEM wiring
2) Electrical failure in the MEIIR circuit
3) Mechanical failure in the MEIIR relay
4) Shift Controller

Shop Talk:
Key on. If the fault is present, the system should automatically detect the problem and set the code. This fault is only detected during system power-up. If the fault is not present at power up, operate the vehicle and attempt to duplicate the driving conditions that triggered the fault code. Possible
triggers include heat, vibration.