<ul> <li><b>Engine Light ON</b>: The Engine Light or Service Engine Soon Warning Light illuminates, indicating an issue with the turbocharger boost control position sensor 'B' circuit. This can be caused by intermittent or erratic signals from the sensor.</li> <li><b>Reduced Engine Performance</b>: The vehicle may experience reduced engine performance due to improper turbocharger boost control. This can result in decreased acceleration and overall power.</li> <li><b>Erratic Engine Behavior</b>: The engine may exhibit erratic behavior such as surging or hesitation. This is often due to the inconsistent signals from the turbocharger boost control position sensor.</li> <li><b>Poor Fuel Efficiency</b>: Fuel efficiency may decrease as the engine struggles to maintain optimal boost levels, leading to inefficient combustion.</li> </ul>

<ul><li>The Turbocharger Boost Control Position Sensor may be faulty, leading to intermittent or erratic signals.</li><li>An open or shorted harness in the Turbocharger Boost Control Position Sensor can disrupt the signal flow.</li><li>Poor electrical connections in the Turbocharger Boost Control Position Sensor circuit can cause inconsistent readings.</li></ul>

<ul> <li><b>Check Technical Service Bulletins (TSB)</b>: Verify if there are any TSBs related to the P2590 code for your vehicle. This can provide known fixes and save diagnostic time.</li> <li><b>Locate TBCPS Sensor</b>: Find the Turbocharger Boost Control Position Sensor 'B' on the turbocharger housing.</li> <li><b>Visual Inspection</b>: Inspect the connector and wiring for damage, such as scraping, rubbing, bare wires, burn spots, or melted plastic. Check terminals for corrosion.</li> <li><b>Clean Terminals</b>: Use electrical contact cleaner and a plastic bristle brush to clean the terminals. Let dry and apply electrical grease.</li> <li><b>Clear DTCs and Retest</b>: Clear the DTCs using a scan tool and see if the P2590 code returns. If not, the issue was likely with the connections.</li> <li><b>Check Turbo Boost Pressure</b>: Test the turbo boost pressure with a mechanical gauge and compare with manufacturer specs. Diagnose any issues with low boost pressure.</li> <li><b>Test TBCPS Sensor Power and Ground</b>: With the Key Off, disconnect the TBCPS sensor connector. Use a Digital Voltmeter to check for 12V or 5V at the power terminal and ground terminal. Repair any open circuits if necessary.</li> <li><b>Test TBCPS Sensor Signal Wire</b>: Move the voltmeter red lead to the signal wire terminal. The reading should be 5V. Repair any open circuits if necessary.</li> <li><b>Replace TBCPS Sensor or PCM</b>: If all tests pass and the P2590 code persists, replace the TBCPS sensor. If the issue continues, consider replacing the PCM, ensuring it is properly programmed.</li></ul>

<p>The DTC code P2590 indicates an issue with the Turbocharger Boost Control Position Sensor 'B' Circuit being intermittent or erratic. This is a critical issue as it can lead to severe engine performance problems, including reduced power and potential engine damage.</p><ul><li><b>Immediate Actions:</b> Inspect and replace the boost control position sensor if necessary.</li><li>Check wiring and connections for any signs of damage or corrosion.</li><li>Ensure the turbocharger system is functioning correctly to prevent further damage.</li></ul><p>Delaying repair can result in significant engine damage and costly repairs.</p>