DTC Troubleshooting: P1840
DTC P1840: CVT Speed Sensor Circuit Forward Rotation Range/Performance
NOTE:
Before you troubleshoot, review the General Troubleshooting Information.
This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P1840 CVT Speed Sensor Circuit Forward Rotation Range/Performance
      

1.
CVT speed sensor check:

CVT speed sensor check
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Turn the vehicle to the OFF (LOCK) mode.

?4.
Raise the vehicle on a lift. Make sure it is securely supported, and allow all four wheels to rotate freely.

?5.
Start the engine.

?6.
Disable the VSA by pressing the VSA OFF button (with VSA).

?7.
Test-drive the vehicle in D position/mode, while monitoring the Direction of Secondary-shaft Rotation in the Data List with the HDS.

?8.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
Direction of Secondary-shaft Rotation
Forward
      

Do the current condition(s) match the threshold?

     
YES
     
     
     
The CVT speed sensor is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If DTC P1840 goes away and the PCM was updated, troubleshooting is complete. If DTC P1840 goes away and the PCM was substituted, replace the original PCM.?
     
NO