A vehicle’s ECU will save a P0894 DTC if the information coming from a number of sensors, including the ISS sensor and OSS sensor, tells it that one or more of the transmission gears are slipping. This can be caused by either a mechanical or electrical failure, and can result in serious transmission damage.
How Serious is the Code?
The P0894 diagnostic trouble code is very serious, because it can be caused by the failure of vital transmission parts. The culprit can be everything from the input speed sensor, to a failed solenoid or torque converter. Continuing to drive your vehicle when it is exhibiting the above symptoms and OBDII code can result in a very expensive repair bill.
Symptoms of a P0894 include:
- Harsh or delayed shifts
- Erratic transmission behavior
- Burnt transmission fluid and/or metal fragments present
- Low or dirty transmission fluid
- Failed solenoid(s)
- Torque converter failure
- Torque converter clutch solenoid/TCC solenoid failure
- Internal mechanical failure
- Failed input speed sensor
- Failed output speed sensor
- Damaged wiring and/or connectors
- Failed ECU/TCM or programming issue
How to Diagnose the Code?
The first thing that should be done when trying to figure out what is causing a P0894 OBDII trouble code, is to check the level and condition of the transmission fluid. If metal fragments and a burnt smell/color are present, then the cause is most likely mechanical failure inside the transmission. If the transmission fluid is clean and bright, check wiring and connectors for signs of damage or a short. The manufacturer’s technical service bulletin/TSB database should also be checked for known solutions and ECU software updates related to the problem. After that, the input speed sensor and output speed sensor will need to be tested with an oscilloscope. Should no issues be found up to this point, then an in-depth mechanical inspection of the transmission and torque converter will be needed.
What Repairs Will Fix P0894?
- Change transmission fluid
- Replace solenoid(s)
- Replace torque converter
- Replace the TCC solenoid
- Replace clutches or other failed mechanical components
- Replace input speed sensor and/or output speed sensor
- Repair damaged wiring or connectors
- Replace or reprogram ECU/TCM
- P0893 – Multiple Gears Engaged
P0895 – Shift Time Too Short
P0896 – Shift Time Too Long