What does it mean?
This diagnostic code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996 and newer). This may include, but is not limited to, vehicles from Volvo, Mercedes Benz, Ford, Dodge, BMW, Land Rover, Citroen, Peugeot, etc. Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
If your vehicle has stored a P0895 code, it means that the Powertrain Control Module (PCM) has received a data input signal from the input and output speed sensors indicating that the shift time interval is insufficient.
The Transmission Control Module (TCM) may be a standalone unit but is most often integrated into a single housing with the Engine Control Module (ECM). This is referred to as the PCM.
The PCM uses input signals from multiple engine and transmission sensors to calculate the automatic shift strategy. A high-pressure pump (inside the transmission) forces fluid through the valve body and into the cam assembly; in addition to lubricating and cooling the transmission. The high-pressure fluid allows the clutches to momentarily disengage from the sprag so that the gear ratio can be smoothly changed. One or more Electronic Pressure Control (EPC) solenoids help regulate the fluid pressure. Electronic Pressure (EP) sensors provide the PCM with relevant data regarding fluid pressure at different points in the transmission. Electronic shift solenoids are used to interrupt the flow of high-pressure fluid so that the transmission shifts when commanded. The PCM uses voltage input signals from the transmission input speed sensor and the transmission output speed sensor to determine if the transmission is shifting effectively.
As with many other automatic transmission malfunctions, a transmission shift time code can be caused by an electrical or mechanical failure. If the PCM detects that the shift time is insufficient, a P0895 code may be stored and a Malfunction Indicator Lamp (MIL) will illuminate.
How severe is this DTC?
A stored P0895 code indicates that a serious shift problem has been detected. The conditions that contributed to the storage of a code of this nature must be rectified as soon as possible.
What are some of the symptoms of the code?
Symptoms of a P0895 fault code may include:
- Insufficient transmission fluid pressure
- Delayed and/or harsh gear engagement
- Irregular transmission shifting patterns
- Unusual noise coming from the transmission
What are some of the common causes of the code?
Causes
of this code may include:
- Faulty high-pressure pump in the transmission
- Catastrophic internal (mechanical) transmission failure
- Shorted wiring for the EPC solenoid or EP sensors
- Faulty EPC solenoid or EP sensor
- Defective PCM or programming error
What are the troubleshooting steps for P0895?
When diagnosing automatic transmission codes, you should start by ensuring that the transmission fluid is clean and the transmission is filled to the appropriate level. If the fluid level is low, locate the source of the leak and repair the condition. Refill the transmission with the recommended fluid and proceed.
If the fluid is excessively dark and has a strong burnt friction material smell, it will need to be replaced. To do this, remove the transmission pan (and drain the torque converter) or flush the transmission (recommended). In either case, you will also want to replace the filter at this time. When removing the transmission pan, be sure to save any debris that may have landed in it. If the pan is relatively free of debris, you can assume the clutches are mechanically intact. If there is an excessive amount of friction material in the pan (and stuck to the magnet), the transmission will require rebuilding by a qualified technician.
A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information will be needed to diagnose a P0895 / P0596 code. A manual transmission fluid pressure gauge will be required to check the actual pressure of the transmission (fluid) pump.
You can use your vehicle information source to locate a Technical Service Bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it may provide useful diagnostic information.
With the transmission filled to the appropriate level with the recommended fluid, proceed to the first step of diagnosis.
Step 1
Use the manual pressure gauge to test the transmission fluid pressure at the appropriate port on the transmission. If the transmission fluid pressure does not meet the recommended specifications, the pump may need to be rebuilt or replaced. A transmission rebuild is usually in order if this is the case. If the fluid meets specifications; proceed to Step 2.
Step 2
Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It is a good idea to record this information before clearing the codes, then test-drive the vehicle until the PCM enters readiness mode or the code resets.
If the PCM enters readiness mode at this point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that contributed to the code being stored may need to worsen before an accurate diagnosis can be made.
Step 3
If the code is immediately reset, the next step in your diagnosis will require you to search your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.
Step 4
Use the DVOM to test the voltage and ground circuits at the EPC solenoid and EP sensors. If voltage and ground are detected, test the EPC solenoid and EP sensors. Any component not meeting the recommended specifications should be considered faulty. If the components are functional, test the signal circuit entering the PCM.
Step 5
If the EPC solenoids and EP sensors are functional and the signal input is present, use the DVOM to test the system circuits. The voltage drop testing method works well for this task. Disconnect all controllers from the circuit before testing resistance with the DVOM.
High-mileage vehicles may experience transmission high-pressure pump failure
Transmission shift time codes can be caused by a low fluid level condition