Power Circuit Troubleshooting
This bulletin applies to all Acura vehicles. When troubleshooting DTCs for a solenoid or motor power supply circuit failure, 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.
Generally, solenoid or motor power supply circuits will have a label of B+, VB or IG1 to indicate a power supply circuit, and SOL or MOTOR is referring to the component being supplied with power, but the label itself may not always read this way.
Be sure you review and verify any power supply circuits going to the control unit first. Checking for blown, missing or misplaced fuses can be a quick first step that can prevent unnecessary troubleshooting.