RELS, signal incorrectly low
Check that there is no damage or short circuits in the external cable harness, particularly the electrical cable to pin 23 which activates the function. If no fault is detected, contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P071A. RELS (Reduced Engine Load at Stop) is a function which reduces gearbox load.The control unit prevents RELS being activated.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 is calibrated to receive a RELS signal and detects an acceleration while RELS is active.
This fault may be caused by a fault on the cable harness or fault on the control unit.