Cause of error code A08

Blower speed does not reach speed calculated by Control Module

Solution for error code A08

1. In Combustion Ail blower operatin? 
Yes: -> 2
No: -> 3

2. Disconnect 4-wire harness from Combustion air blower. Does combustion air blower speed increase?
Yes: -> 4
No: Replace Combustion air blower

3. Are 3-wire and 4-wire harnesses connected to combustion air blower? 
Yes: -> 5
No: Connect harness

4. Disconnect harness from control module J9. Continuity in each wire of 4-wire harness( yellow, red. white, black)
Yes: Replace control module
No: Replace harness

5. Disconnect harness from control module J9 connector. Measure voltage between two pins, J9-2 and J9-3 on control module (second en third pins of J9, count from outside) Is the voltage 120Vac=/-10% available?
Yes: -> 6
No: Replace control module

6. Disconnect 3-wire harness from coombustion air blower. Measure continuity in each wire. Continuity in each wire? 
Yes: Replace combustion air blower
No: Replace Harness