DTC Code P0846 – What does this code mean?

<ul> <li><a href="/problems/engine-warning-light-on"><b>Engine Light ON</b></a>: The check engine light or service engine soon warning light illuminates, indicating a potential issue with the transmission fluid pressure sensor/switch 'B' circuit.</li> <li><b>Transmission Performance Issues</b>: Drivers may experience erratic or harsh shifting, delayed gear engagement, or slipping gears, which can be linked to the transmission fluid pressure sensor/switch 'B' circuit malfunction.</li> <li><a href="/problems/high-fuel-consumption"><b>Reduced Fuel Efficiency</b></a>: A malfunctioning transmission fluid pressure sensor/switch can lead to inefficient transmission operation, potentially causing reduced fuel efficiency.</li> </ul>

<ul><li>The transmission fluid pressure sensor/switch 'B' may be faulty, leading to incorrect pressure readings and triggering the error code.</li><li>An open or shorted harness in the transmission fluid pressure sensor/switch 'B' can disrupt the signal, causing performance issues.</li><li>Poor electrical connections in the circuit of the transmission fluid pressure sensor/switch 'B' can result in intermittent or incorrect signals, affecting transmission performance.</li></ul>

<ul> <li><b>Check Technical Service Bulletins (TSB)</b>: Review TSBs for known issues and fixes related to P0846. Address any power-related codes or multiple pressure sensor/switch codes first.</li> <li><b>Locate and Inspect TFPS</b>: Find the Transmission Fluid Pressure Sensor/Switch, usually on the valve body or transmission case. Inspect the connector and wiring for damage or corrosion.</li> <li><b>Clean and Reconnect Terminals</b>: If corrosion is found, clean terminals with electrical contact cleaner and a plastic brush. Apply electrical grease and reconnect.</li> <li><b>Clear Codes and Test</b>: Use a scan tool to clear DTCs. If P0846 returns, proceed with further testing.</li> <li><b>Test TFPS Circuit Voltage</b>: With the key on and engine off, use a DVOM to check voltage at the TFPS connector. Verify against manufacturer specifications.</li> <li><b>Test TFPS Resistance</b>: Use an ohmmeter to check resistance at the TFPS. Compare readings to manufacturer specifications while wiggling the connector.</li> <li><b>Evaluate Results</b>: If voltage or resistance tests fail, repair wiring or replace the TFPS. If tests pass but P0846 persists, consider PCM/TCM or internal transmission issues.</li></ul>

<p>The <b>P0846</b> code indicates a <b>critical</b> issue with the Transmission Fluid Pressure Sensor/Switch 'B' Circuit. This can lead to improper transmission operation, causing erratic shifting or failure to shift, which may result in <ul><li>loss of vehicle control</li><li>increased wear on transmission components</li></ul>. Immediate attention is required to prevent potential transmission damage and ensure vehicle safety.</p>