What Does It Mean?
This diagnostic 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 VW, Audi, Honda, Ford, Kia, Lincoln, Hyundai, etc. Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
If your vehicle has stored a P0819 code, it means that the Powertrain Control Module (PCM) has detected a malfunction between the up/down shift switch and the transmission range switch (gear shift range). This type of code is typically limited to vehicles with automatic transmissions and paddle or sport shifters.
The Transmission Control Module (TCM) may be a standalone module or part of the PCM. The up/down shift (paddle) buttons are usually located on the steering wheel horn pad near the driver’s finger positions. They are used as a type of sport shifter, typically in high-performance models. The PCM monitors the transmission range switch to ensure that the gear selection is consistent with the input signals from the up/down shift switch. Additionally, the PCM monitors the up/down shift switch and the transmission range circuit voltage to ensure both are within established parameters.
If the PCM detects that the transmission gear selection is not consistent with the gear selection signal entered by the up/down shift switch or if the circuit voltage is not within the allowed parameters, a P0819 code may be stored and a Malfunction Indicator Lamp (MIL) illuminated. Several ignition cycles (with a failure) may be required for the MIL to light up.
How Severe Is This DTC?
A stored P0819 code indicates that a serious electrical issue or a type of mechanical failure has occurred. In any case, the conditions that contributed to the storage of a code of this nature should be rectified as soon as possible.
What Are Some of the Symptoms of the Code?
Symptoms of a P0819 fault code may include:
Manual up/down shift function (paddle) disabled
The gear shift indicator reflects an incorrect gear
No symptoms may appear
What Are Some Common Causes of the Code?
Causes
of this code may include:
Faulty up/down shift switch
Bad transmission range (shift) sensor
Short-circuited or open circuits in the up/down shift switch or transmission range circuit
Faulty PCM or programming error
What Are the Troubleshooting Steps for P0819?
A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information will be needed to diagnose a P0819 code.
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.
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 note this information before clearing the codes, then test the vehicle until the PCM enters readiness mode or the code resets.
If the PCM enters readiness mode at that point, the code is intermittent and may be much harder to diagnose. If this is the case, the conditions that contributed to the code storage may need to worsen before an accurate diagnosis can be made.
If the code is immediately reset, the next step in your diagnosis will require you to consult your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.
Step 1
Use the DVOM to test the voltage, ground, and signal output at the appropriate up/down shift and transmission range switches. Typical up/down shift circuits consist of battery voltage (when activated) or ground (when deactivated).
Step 2
Use your vehicle diagnostic information source and the DVOM to test the up/down shift and transmission range switches as needed. Replace switches that do not test within system specifications.
Step 3
If the system circuits are functional, use the DVOM to test the up/down shift switch and transmission range switch circuits to the PCM or transmission. Disconnect all controllers before using the DVOM for testing.
Up/down shift correlation codes to transmission range are most often attributed to a switch failure