What does it mean?
P1747 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Hydraulic Control System (Cut Valve A Stuck ON or Cut Valve B Stuck OFF) .
Symptoms
- Very harsh engagement or a hard bump when a specific gear applies
- Transmission locked in one gear or unable to select certain ratios
- Binding or dragging feel when moving off, as if two elements apply at once
- MIL (check engine lamp) on with a transmission warning lamp
- Overheating fluid, burnt smell and reduced acceleration
Likely causes
- Valve stuck in the applied position by varnish build-up or debris
- Excessive line pressure holding the valve against its stop
- Worn valve body bore or a damaged valve land allowing cross leakage
- Broken return spring that can no longer push the valve back
- Solenoid stuck open or a drive circuit shorted to ground keeping it energised
- Contaminated fluid and a restricted filter after a missed service
- Damaged separator plate gasket linking two circuits together
How to fix it
- Verify fluid level and condition, and note any burnt smell or dark colour first
- Record commanded gear and actual ratio on live data during a road test
- Measure line pressure with a gauge and confirm it is not running above specification
- Command each related solenoid with a scan tool and watch the hydraulic response
- Check the solenoid drive circuits for a permanent short to ground with the solenoids unplugged
- Remove and inspect the valve body, freeing and cleaning the cut valves and their bores
- Replace worn valve body parts or the assembly, then service the fluid and filter and road test