John Deere 923.12 – ATC: Circulation Blower Motor Driver Circuit Fault

Triggered when the power module (HF) PC6 detects a current draw in excess of 1 amp at one or both of the fan motor outputs (leads 2043 and/or 2047) while the fan motors (M07 and M10) are commanded off. This condition typically indicates a short in the circuit, a grounded fan motor driver unit, or an internal fault within the power module itself.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6120 to 6420
• 6120L to 6520L
• 6020 to 6920S
• 7715
• 7815
• 7720
• 7820
• 7920
• 7130 to 7530 Premium
• 8120 to 8520
• 8230T
• 8330T
• 8430T
• 8310RT
• 8335RT
• 8360RT
• 9230
• 9330
• 9430
• 9530
• 9630

1. 1

   Verify if code ATC 000923.01 (voltage supply problem for the fan motor outputs) is also active. If it is, address 000923.01 first.

2. 2

   Restart the engine to verify if the active Service Code reappears, as communication messages can sometimes be corrected by a simple restart.

3. 3

   Check the power supply to the Fan Motor Driver Unit (A59).

4. 4

   Perform a continuity and short-to-ground test on the ClimaTrak harness, specifically checking leads 2043 and 2047 between the Circulation Blower Motor and the Blower Motor Driver.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Inspect Wiring

   Visually inspect the wiring harness connecting the ATC power module (PC6) to the fan motor driver unit and the circulation blower motors (M07 and M10). Look for chafed wires that may be shorting to the chassis ground.

3. 3

   Test the Driver Unit

   If the wiring is intact, test the Fan Motor Driver Unit for an internal short. If it is grounded or open, it must be replaced.

4. 4

   Test the Power Module

   If the driver unit tests fine but current is still bleeding through when the system is off, the PC6 Power Module (HF) has an internal fault and requires replacement.

5. 5

   Recondition and Verify

   Repair any damaged wiring, reconnect the components, and perform an Operational Check for the Fan Motors via the CommandCenter display. Clear the codes and run the HVAC system to ensure the code does not return.