What does it mean?
P1744 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Problem in Shift Control System; Shift Valve E Stuck ON .
Symptoms
- Transmission stuck in one gear or engaging an unexpected ratio
- Harsh shift shock or a hard clunk during a particular change
- Missing gears with limited acceleration and a low top speed
- MIL (check engine lamp) on with a transmission warning
- Fluid overheats and smells burnt after a short drive
Likely causes
- Shift valve E stuck in a varnished or scored valve body bore
- Debris from clutch or metal wear trapped between the valve and its bore
- Weak or broken valve return spring
- Solenoid feeding the valve stuck open or shorted in its circuit
- Contaminated ATF and a blocked filter, often after long service intervals
- Excessive line pressure holding the valve against its stop
- Worn valve body separator plate or a leaking gasket cross feeding circuits
How to fix it
- Check fluid level and condition and note the colour, smell and any metal on the dipstick
- Log commanded gear against calculated ratio on live data during a road test
- Command the related solenoids with a scan tool and confirm the ratio responds each time
- Measure solenoid resistance and check the drive circuit for a permanent short to ground
- Fit a pressure gauge and compare line pressure with the specification in each range
- Remove the valve body, extract valve E and check it slides freely in a clean bore
- Clean or replace the valve body and solenoids, then complete a full fluid and filter service