P0894 code definition
The P0894 trouble code detects an issue with the vehicle’s automatic transmission component.
What the P0894 code means
The P0894 code is an OBD-II trouble code signaling a problem with the transmission component slipping. The powertrain control module (PCM) is responsible for altering the gear rations of the automatic transmission, as this helps control the vehicle’s speed, acceleration, fuel economy, and overall engine performance. When the ratio is one of the vehicle’s gears is not perceived to be consistent with the what the PCM is dictating, the P0894 trouble code will be detected.
What causes the P0894 code?
There are a number of different issues that can cause the P0894 code to be detected, including:
- Mechanical failures within the internal transmission
- Transmission fluid is low, empty, or contaminated
- The internal transmission fluid passages are clogged or blocked
- Malfunctioning shift solenoids
- Faulty transmission control module (TCM)
- Malfunctioning PCM
What are the symptoms of the P0894 code?
When the P0894 trouble code is detected, the vehicle’s Check Engine Light will usually illuminate on the instrument cluster. Most of the other symptoms are issues with the transmission, such as an inability to switch into or out of a certain gear, an overheating transmission, transmission slippage, and rough shifting. The vehicle may also experience a notable decrease in fuel efficiency.
While all of these symptoms are relatively common with the P0894 code, it is also common for no noticeable symptoms to occur when the code is first detected.
How does a mechanic diagnose the P0894 code?
The P0894 code should be diagnosed with a standard OBD-II trouble code scanner. A trained technician will examine the freeze frame data from the scanner, which will allow them to gain insight into the P0894 code, and see if any other trouble codes are present. The codes should then be reset, and the vehicle restarted and taken for a test drive. If the codes do not return, the issue was likely triggered erroneously, or as an intermittent error.
If the P0894 code remains after resetting and restarting, the mechanic will begin by assessing the transmission fluid. If the fluid is low, it will be replenished, and if it is dirty it will be emptied, flushed, and refilled.
If the code is still not resolved, the technician will assess the internal transmission, and look for issues such as damaged wires, faulty connectors, and damaged harnesses. Any issues in the internal transmission should be replaced.
If the issue does not lie with the transmission fluid or a mechanical issue in the internal transmission, then the technician can look for other potential problems, such as with the shift solenoids or the control modules.
Whenever a component is repaired or replaced, the mechanic should reset the trouble codes and restart the vehicle, to see if the issue has been resolved.
Common mistakes when diagnosing the P0894 code
The most common mistake when diagnosing the P0894 code comes from a failure to follow the standard OBD-II trouble code diagnosis protocol. The protocol for assessing a trouble code should be followed at all times. Failure to do so often results in replacing fully functioning shift solenoids, when wires, connectors, or harnesses (more affordable fixes) were the actual problem.
How serious is the P0894 code?
The P0894 trouble code usually doesn’t keep a car from being able to drive. However, the issue causing the code may be causing damage to the transmission. Failure to have the P0894 code addressed can result in severe damage to the transmission, and the system may need a rebuild.
What repairs can fix the P0894 code?
Some of the repairs for the P0894 trouble code include:
- Topping off the transmission fluid
- Replacing the transmission fluid
- Replacing the wires, connectors, and harnesses in the internal transmission
- Replacing the shift solenoids
- In rare cases, replacing the TCM or PCM
Additional comments for consideration regarding the P0894 code
The P0894 code only exists in vehicles with automatic transmissions. It is common for other gear ratio trouble codes to be present when the P0894 code is detected. If the PCM needs to be replaced, it will also need to be reprogrammed.
Need help with a P0894 code?
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.