What does it mean?
P1704 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: 2-4 Brake Timing Control Solenoid Valve Circuit Malfunction .
Symptoms
- MIL on with a transmission warning light
- Harsh or flaring 2-3 and 3-4 shifts
- Shift shock felt clearly in the mid gears
- Transmission entering limp mode and holding one gear
- Slipping under acceleration in the mid range
- Burnt smell from the transmission fluid in advanced cases
Likely causes
- Open winding or internal short in the 2-4 brake timing control solenoid
- Wiring fault in the solenoid circuit: open, short to ground or short to battery positive
- Fluid intrusion and corrosion in the transmission case connector
- Contaminated fluid or varnish making the solenoid valve stick in the bore
- Damaged internal transmission harness or lead frame
- Worn 2-4 brake band or clutch pack so the timing correction never reaches its target
- Failed transmission module output driver
How to fix it
- Check fluid level, colour and smell before any electrical work
- Command the solenoid with the scan tool and watch current draw and pressure response
- Measure the solenoid winding resistance at the case connector against the specification
- Test the control circuit for open, short to ground and short to battery with the module disconnected
- Inspect the case connector and internal harness for fluid wicking and corrosion
- Replace the solenoid or solenoid pack if the resistance is out of specification
- If the electrical side checks out, inspect the valve body and the 2-4 brake apply circuit and service the filter and fluid