Gearbox pressure switch 1 (PS1), circuit low
â–¶ How to fix
Check that the cable harness between the gearbox and the control unit is not damaged.Contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
Detection
PS1 is not pressurised when it should be.
Possible cause
A possible cause of the fault may be damage in the cable harness or a defective PS1.