What does P0884 mean?
This diagnostic trouble code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996-newer). This may include, but is not limited to, vehicles from Hyundai, Allison, Range Rover, BMW, Chevy, Kia, Dodge, Jeep, etc. Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
If your vehicle has stored a P0884 code, accompanied by a Malfunction Indicator Lamp (MIL) and/or a Transmission Control Module (TCM) light, it means the Powertrain Control Module (PCM) has detected an intermittent voltage condition in the TCM power supply input circuit.
While some Transmission Control Modules (for OBD-II equipped vehicles) are integrated into the PCM, most are standalone components. TCM-related codes are stored as P-codes, B-codes, or even U-codes, depending on the vehicle’s make and model. If a P0884 code is stored, it is highly likely that other PCM and/or TCM codes are also stored. Anti-lock Brake System (ABS) codes may also be recorded.
The electronic transmission control systems of OBD-II equipped vehicles are managed using a network of computers (called control modules). This involves constant communication between the various control modules via the Controller Area Network (CAN).
The CAN is a complex system of wiring and connectors used to transmit data between the TCM and PCM. Data (including stored codes) can also be shared with other controllers via the CAN. Transmission input and output speed (RPM), vehicle speed, and wheel speed are all shared among multiple controllers. This data is used not only for comparison purposes in electronic traction control systems but also in anti-lock braking systems and electronic stability control systems.
The PCM uses input signals from various 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 separate from the sprag so the gear ratio can be smoothly changed. One or more Electronic Pressure Control (EPC) solenoids help regulate 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 the transmission shifts when commanded. The PCM uses voltage input signals from the transmission input speed sensor and transmission output speed sensor to determine if the transmission is shifting effectively.
As with many other automatic transmission malfunctions, a transmission control system code can be caused by an electrical or mechanical failure. If the PCM detects a malfunction, the MIL should illuminate and a P0884 code will be stored.
How severe is this DTC?
If this code is stored, you may have noticed your transmission shifting much harder than normal. If your vehicle has set a P0884 code, it should be diagnosed as soon as possible.
What are some of the symptoms of the code?
Symptoms of a P0884 fault code may include:
Electronic Traction Control disabled
Irregular transmission shifting patterns
Transmission failure to shift
Other related codes
ABS disabled
What are some common causes of the code?
The Causes
of this code may include:
Faulty relay or blown fuse (fuse link)
Vehicle Speed Sensor failure
Open or shorted circuits in the CAN
Mechanical transmission failure
Defective TCM, PCM, or programming error
What are the P0884 troubleshooting steps?
You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P0884 code. An oscilloscope can also be very useful for diagnosing various speed sensors.
You can save time by searching for Technical Service Bulletins (TSBs) that match the stored code, the vehicle (year, make, model, and engine), and the symptoms presented. This information can be found in your vehicle information source. If you find the correct TSB, it might provide a quick fix for your diagnosis.
After connecting the scanner to the vehicle’s diagnostic port and retrieving all stored codes and relevant freeze frame data, note the information (in case the code proves to be intermittent). After that, clear the codes and test drive the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.
The code may be more difficult to diagnose if the PCM enters readiness mode at this point, as the code is intermittent. The condition that caused the P0884 to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, proceed with the diagnosis.
You can obtain connector face views, connector pinout charts, component location charts, wiring diagrams, and diagnostic flowcharts (related to the code and the specific vehicle) using your vehicle information source.
Perform a visual inspection of the associated wiring and connectors. Repair or replace any wiring that is cut, burned, or damaged.
Use the DVOM to test the voltage and ground circuits at the TCM and/or PCM. If no voltage is detected, check the system fuses. Replace any blown or faulty fuses as needed and retest.
If voltage and ground are detected at the TCM, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the component in question and the PCM. If voltage is found there, suspect a faulty TCM, PCM, or a programming error.
P0884 is typically stored due to a faulty ignition relay