Technical Description of OBD-II Trouble Code
Correlation between Up and Down Shift Switch and Transmission Range
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to many OBD-II vehicles (1996-newer). This includes vehicles from VW, Audi, Honda, Ford, Kia, Lincoln, Hyundai, etc. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration.
If your vehicle has stored a code P0819, it means that the powertrain control module (PCM) has detected a malfunction between the upshift/downshift switch and the transmission range (shift range) switch. This code is usually found in vehicles with automatic transmissions and paddle or sport shifters.
The transmission control module (TCM) may be a separate module or part of the PCM. Upshift/downshift (paddle) shifter buttons are typically located on the steering wheel horn pad near the driver’s fingers. They are used as a type of sport shifter, usually in high-performance models. The PCM monitors the transmission range switch to ensure that the gear selection aligns with the upshift/downshift switch input signals. Additionally, the PCM monitors the upshift/downshift switch and transmission range circuit voltage to ensure that both are within the established parameters.
If the PCM detects that the transmission gear selection does not match the gear selection signal input from the upshift/downshift switch, or if the circuit voltage is outside the allowable parameters, a code P0819 may be stored and the malfunction indicator lamp (MIL) may illuminate. Multiple ignition cycles (with a failure) may be required for MIL illumination.
What is the severity of this DTC?
A stored code P0819 indicates that either a serious electrical issue or some type of mechanical failure has occurred. In any case, it is important to rectify the conditions that led to the storage of this code as quickly as possible.
What are some of the symptoms of the code?
Symptoms of a P0819 trouble code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P0819 troubleshooting steps?
To diagnose a code P0819, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle-specific diagnostic information.
You can use your vehicle information source to find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model, as well as the engine size, stored code/s, and exhibited symptoms. If you find one, it may provide helpful diagnostic information.
Use the scanner (connected to the vehicle diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It is advisable to write down this information before clearing the codes, and then test-drive the vehicle until the PCM either enters readiness mode or the code is reset.
If the PCM enters readiness mode at this point, the code is intermittent and may be more difficult to diagnose. In such cases, the conditions that led to the storage of the code may need to worsen before an accurate diagnosis can be made.
If the code is immediately reset, the next step in your diagnosis will involve searching your vehicle information source for diagnostic flowcharts, connector pin-out charts, connector face views, and component testing procedures/specifications.
Step 1
Use the DVOM to test the voltage, ground, and signal output at the appropriate upshift/downshift and transmission range switch. Typical upshift/downshift switch circuits consist of either battery voltage (when activated) or ground (when deactivated).
Step 2
Use your vehicle diagnostic information source and the DVOM to test the upshift/downshift and transmission range switches as required. Replace switches that do not test within the system specifications.
Step 3
If the system circuits are functional, use the DVOM to test the upshift/downshift switch and transmission range switch circuits to the PCM or transmission. Disconnect all controllers before using the DVOM for testing.
