High reference voltage on the sensor circuit
Check the control unit cable harness.Contact an Allison dealer.The fault code can be cleared manually using SDP3 or using Allison's diagnostic tool. The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
What you'll see
No driver-visible symptom recorded.
System reaction
Yellow warning lamp comes on.The fault code is stored in the memory.Other fault codes may be active depending on the 5 V reference voltage function.
Diagnostic depth
The 5 V reference voltage from the control unit is too high for a set time period.
Possible causes:Short circuit, high resistance or open circuit on the control unit cable harness.Defective connector causes the pins to short-circuit against each other.Play or moisture in the switches due to missing cover plug.Defective control unit.