Loss of the VBV Torque Motor Control through the Channel B on Engine 1 and Channel A on Engine 2

TASK 73-29-00-810-902-A
Loss of the VBV Torque Motor Control through the Channel B on Engine 1 and Channel A on Engine 2

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 73-29-00-810-889-A	Loss of the VBV Torque Motor Control - Engine 1 - Channel B
TSM TASK 73-29-00-810-890-A	Loss of the VBV Torque Motor Control - Engine 2 - Channel A
AMM 73-29-00-710-040	Operational Test of the FADEC on the ground (with Engine Motoring)

3. Fault Confirmation
Subtask 73-29-00-710-214-A ** ON A/C NOT FOR ALL

A. Do the operational test of the FADEC 1B and 2A on the ground (with engine motoring) AMM 73-29-00-710-040.

4. Fault Isolation
Subtask 73-29-00-810-194-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance messages:

J8, HMU (VBV TM), ECU on the channel 1B
and
J7, HMU (VBV TM), ECU on the channel 2A

(1) Do the trouble shooting procedure (Ref. TSM TASK 73-29-00-810-889).
(2) Do the trouble shooting procedure (Ref. TSM TASK 73-29-00-810-890).

[Rev.8 from Aug 2018] 2026.04.04 04:36:02 UTC