In order to shift gears, the transmission has to route pressurized transmission fluid down the right channel. To do this, a little electromechanical device called the 2-3 shift solenoid is employed to channel pressurized ATF through the valve body. If a low voltage condition (like a short) is detected, then a P1845 diagnostic trouble code will be stored.
How Serious is the Code?
A P1845 DTC is fairly serious, especially since it has to do with the core shifting function of the transmission. Failure to address the problem will result in serious drivability issues, and eventually a nonworking transmission.
Symptoms of a P1845 include:
- Excessively hard shifts
- Delayed gear changes
- Vehicle refuses to move in a forward gear
- Limp mode
- Engine stalling
- Transmission overheating
- Low on transmission 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?
Sometimes the simplest answer is the right one, and when it comes to diagnosing a P1845 OBDII diagnostic trouble code, it may pay to look at the most obvious culprit first: Dirty transmission fluid. Sludge, metal fragments and reduced viscosity can impact the way that a 2-3 shift solenoid performs. If the transmission fluid is in good condition, the wiring and connectors should be inspected. Should no issues be found, then the 2-3 solenoid could be at fault.
What Repairs Will Fix P1845?
- 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
P1847 – 2-3 Shift Solenoid High Voltage