What does it mean?
P1847 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: 2-3 Shift Solenoid Circuit High Input (4T80-E) .
Symptoms
- Check engine lamp on with a transmission warning
- No 2-3 upshift, so the engine screams in the lower gear at road speed
- Harsh or delayed shift into third when it happens at all
- The transmission holds a default gear as a protective measure
- Higher fuel consumption, more engine noise and poor drivability
Likely causes
- Open circuit in the solenoid control wire, most often at the transmission case connector
- Solenoid winding open internally after heat cycling or vibration
- Corroded, spread or backed-out terminal adding resistance to the circuit
- Internal harness broken or its connector left unlatched after valve body work
- Lost solenoid supply because of a blown fuse, a failed relay or a corroded splice
- Poor module ground so the driver circuit cannot switch correctly
- Module output driver open internally
How to fix it
- Read all codes and the freeze frame, and inspect the fluid level and condition first
- Check the case connector for corrosion, moisture, backed-out pins and a loose lock tab
- Measure the solenoid resistance at the case connector and compare with specification; an open reading confirms the fault
- Test the control and feed wires for continuity between the module connector and the case connector
- Verify supply voltage at the solenoid feed with the key on, and check the fuse and relay
- If the external circuit is good, drop the pan and inspect the internal harness and solenoid connector
- Fit a new solenoid or repair the wiring, then confirm the 2-3 shift on a road test through the full range