A shift solenoid is a little spring-loaded device that directs the flow of pressurized transmission fluid, which then actuates a gear change. So in the case of the 2-3 shift solenoid, it activates the 2nd to 3rd gear change. If your vehicle has a P1847 diagnostic trouble code, it means that the ECU has detected a high-voltage condition, which typically means a short or open circuit.
How Serious is the Code?
The P1847 DTC is a pretty serious code, because it indicates a potentially serious problem. One that can not only cause serious drivability issues, but could also render your vehicle unusable.
Symptoms of a P1847 include:
- Excessively harsh gear changes
- Delayed shifts
- Vehicle unable to move in a forward gear
- Limp mode
- Engine stalling
- Transmission overheating
- Transmission is low on fluid
- Dirty transmission fluid/filter
- Blocked hydraulic passages
- Damaged or corroded wiring/connectors
- Bad 2-3 shift solenoid
- Faulty transmission pump
How to Diagnose the Code?
Even though a vehicle may display a P1847 OBDII diagnostic trouble code, the cause might be as simple as dirty transmission fluid or a clogged transmission filter. If the ATF is in good condition, then all the wiring and connectors on the transmission wiring harness should be examined for signs of corrosion or a short. Should no issues be found at this point, the 2-3 shift solenoid could be to blame.
What Repairs Will Fix P1847?
- Service the transmission (i.e. change the transmission fluid/filter)
- Repair or replace damaged wiring/connectors
- Replace the 1-2 shift solenoid
- Repair or replace the transmission pump
- Repair or replace the valve body
P1845 – 2-3 Shift Solenoid Low Voltage