What does it mean?
P1746 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Hydraulic Control System (Cut Valve A Stuck OFF or Cut Valve B Stuck ON) .
Symptoms
- Harsh, delayed or completely missing engagement when selecting Drive or Reverse
- Slipping under load with engine RPM rising while road speed does not
- Certain gears unavailable, or the transmission stuck in one ratio
- MIL (check engine lamp) on with a transmission warning
- Shudder at light throttle and rising transmission temperature
Likely causes
- Cut valve stuck in its bore by varnish, sludge or a trapped particle
- Scored or worn valve body bore letting the valve hang or leak past
- Weak, broken or dislodged valve return spring
- Contaminated ATF with a blocked filter and loaded solenoid screens
- Low line pressure from low fluid, a worn pump or an internal circuit leak
- Faulty solenoid or wiring fault in the circuit that pilots the cut valve
- Warped valve body or a leaking separator plate gasket cross feeding circuits
How to fix it
- Check fluid level, colour and smell, and look for debris on the pan magnet
- Log gear command against calculated ratio during a road test to see which circuit fails
- Connect a pressure gauge and compare line pressure with specification in each range
- Command the related solenoids with a scan tool and watch for a pressure or ratio change
- Measure solenoid resistance and check the drive circuits for opens and shorts
- Remove the valve body, extract the cut valves and confirm they slide freely in a clean bore
- Clean or replace the valve body, then complete a full fluid and filter service