Troubleshooting DTCs for a solenoid or motor power supply circuit failure on Honda? Keep in mind that even though the control unit activates these components, the power supplied may come from a dedicated circuit and its own separate fuse. This is most commonly overlooked when troubleshooting transmission or VTEC solenoid circuits. If the troubleshooting leads you to replace a control unit, make sure you understand and inspect all the power supplies to that control unit first.
Checking for blown, missing or misplaced fuses can be a quick first step that can prevent unnecessary diagnostics.
Generally, solenoid or motor supply circuits will have a label of B+, VB or IG1 to indicate a power supply circuit. SOL or MOTOR is referring to the component being supplied power, but the label itself may not always read this way.
