Some solenoid drivers use a stronger initial current followed by a lower holding level. A reduction after actuation can therefore be intentional rather than a supply failure.

Interpreting the evidence

Record the complete event and compare current with the commanded state. If the valve fails to move or remain engaged, distinguish the initial actuation from the holding phase. Check the external circuit and the correct control specification before considering driver repair.

Keep this evidence

Send the valve function and a capture including switch-on and steady operation.

Do not apply continuous battery voltage to a solenoid designed for controlled current. The approved test method matters.

Speak to AXION

For complex vehicle-electronics diagnostics, send your vehicle details and fault report. Workshop assessment is in Didcot, Oxfordshire. Suitable postal or remote work is confirmed before booking.

Technical background from Texas Instruments. The referenced design explains the principle; the vehicle-specific procedure determines the repair.