P1787: 2-1 Downshift Error
MediumPowertrainTransmission
What does P1787 mean?
P1787 is a diagnostic trouble code indicating "2-1 Downshift Error". This code relates to your vehicle's transmission and should be diagnosed to determine the root cause. The severity level helps indicate how urgently this should be addressed.
Common causes
- Low or degraded transmission fluid
- Worn clutch packs or bands
- Faulty shift solenoid
- Wiring issue to the transmission control module
- Failing torque converter
What should you do?
Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.
Get a diagnosis for YOUR car
Code P1787 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.