Solenoid PCS2, open circuit
Check the cable harness between the gearbox and control unit, particularly the electrical cables to pins 71 and 52 on the control unit. If no fault is found, contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P0964.The fault code is set when the control unit has detected an open circuit in the PCS2 solenoid return circuit for more than 2 seconds.The fault code can only be set during control unit start-up or if the engine speed is greater than 200 rpm. The control unit shuts off all solenoids.The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
Diagnostic depth
The control unit has detected an open circuit in the PCS2 solenoid return circuit.
A possible cause of this fault code is a damaged cable harness in the solenoid electric circuit.