What does it mean?
P1749 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Electronic Pressure Control Solenoid Circuit Malfunction .
Symptoms
- Very harsh, jolting shifts because the transmission defaults to full line pressure
- Firm bang into gear when selecting Drive or Reverse
- MIL (check engine lamp) on with a transmission warning
- Limp mode limiting gear selection and vehicle speed
- Driveline shock during light throttle upshifts and rising fluid temperature
Likely causes
- Open circuit in the solenoid feed or return wire
- Short to ground on the solenoid drive circuit
- Open winding inside the pressure control solenoid
- Corroded case connector or a broken pin inside the transmission
- ATF contaminated internal harness with damaged insulation
- Low system voltage from a weak battery or failing charging system
- Module output driver failure, considered after the solenoid and wiring are proven
How to fix it
- Test the battery and charging system, then check the transmission fuses and feed
- Read live data and compare commanded pressure control current with the actual value
- Measure the solenoid resistance at the case connector and compare with specification
- Check the drive circuit for an open and for a short to ground with the solenoid disconnected
- Perform voltage drop tests on the module feed and ground while the circuit is loaded
- Inspect the case connector and internal harness for corrosion, fluid and chafing
- Replace the solenoid or repair the wiring, then confirm shift quality and line pressure on a road test