Error Code P0818 is defined as Driveline Disconnect Switch Input Circuit. Error Code P0818 is a generic trouble code, meaning it applies to all cars with the OBD-II system, especially those made from 1996 up to present. This includes cars from, but not limited to, BMW, Mini, Jaguar, Toyota, Land Rover, and Volvo. Specifications on the definition, troubleshooting, and repairs, of course, vary between make,r model and powertrain configuration.
If your 2018 Mazda MX-5 rf stores the Error Code P0818, this means the PCM (powertrain control module) has determined a malfunction in the transfer case neutral safety switch (also known as shift selector switch) circuit. This code only applies to AWD or 4WD automatic transmission cars.
The transfer case neutral safety switch input circuit is usually integrated into the neutral safety switch or the shift selector switch. When the transfer case is positioned in neutral (driveline disconnected), a voltage signal is sent to the transmission control module (TCM) or the PCM. The controller also checks the transfer case neutral safety switch circuit voltage if the ignition is at ON position. The TCM can be either a standalone module or part of the PCM.
If the PCM is unable to determine the right amount of voltage on the transfer case neutral safety switch circuit, with the transfer case apparently in or neutral, then this error code will be stored and will activate the Check Engine light. In some cases, multiple ignition cycles (with a failure) may be needed to activate the Check Engine light.
In other cases, your 2018 Mazda MX-5 rf may not show symptoms at all.
You will also need a diagnostic scanner, DVOM (digital volt/ohmmeter), and a source of 2018 Mazda MX-5 rf diagnostic information.
Use your 2018 Mazda MX-5 rf’s information to find the TSB (technical service bulletin) that matches the specifics of your 2018 Mazda MX-5 rf (make, model, engine size, symptoms, and codes stored). This could help for a more thorough diagnosis.
Use the scanner (connected to your 2018 Mazda MX-5 rf diagnostic connector) to retrieve all stored codes and pertinent freeze frame data. It is a good idea to write this information down before clearing the codes then test-drive your 2018 Mazda MX-5 rf until the PCM either enters readiness mode, or the code is reset.
If the PCM enters readiness mode at this time, the code is intermittent and may be much more challenging to diagnose. If this is the case, the conditions which contributed to the code being stored may need to worsen before an accurate diagnosis can be made.
If the code is immediately reset, the next step of your diagnosis will require that you search your 2018 Mazda MX-5 rf information source for diagnostic flow-charts, connector pin-out charts, connector face views, and component testing procedures/specifications.
Test the voltage, ground, and signal output at the right downshift switch using the DVOM. Typically, the downshift switch circuits consist of either the battery voltage (when activated) or the ground (if deactivated).
If all the system circuits are working correctly, then test the downshift switch circuits to the PCM or the transmission using the DVOM. Make sure you disconnect all controllers before using the DVOM for testing.
Test the downshift switches using your source of 2018 Mazda MX-5 rf diagnostic information and the DVOM. Switches that don’t test within the system’s specifications must be replaced.
Error codes that refer to the transfer case neutral safety switch input are usually attributed to neutral safety switch failure.
This error code may come with a no-start condition, which means it is either an electrical or mechanical problem. Nevertheless, it should be addressed as soon as possible.