Symptoms
Symptoms of a P2590 code may include:
- Malfunction indicator light illuminated
- Poor performance
- Hesitation during acceleration
- Decreased fuel economy
Causes
Potential causes for this code definition are as follows:
- Open in the TBCPS sensor signal circuit – most likely
- Short to voltage in the signal circuit to the TBCPS sensor
- Short to ground in the TBCPS sensor signal circuit
- Open in power or ground to the TBCPS sensor – most likely
- Failed TBCPS sensor – possible
- Failed PCM – unlikely
Diagnostic and Repair Procedures
A good starting point is always to check the technical service bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money when diagnosing.
Next, locate the TBCPS sensor on your specific vehicle. This sensor is typically directly screwed/bolted into the turbocharger housing. Once located, visually inspect the connector and wiring. Look for scratches, rubbing, bare wires, burns, or melted plastic. Disconnect the connector and carefully inspect the terminals (the metal parts) inside the connector. See if they appear burned or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.
If you have a scan tool, clear the diagnostic codes from memory and see if the P2590 code returns. If not, the connections were likely your problem.
If the P2590 code returns, ensure you have good turbo boost pressure by testing with a mechanical pressure gauge. Check your vehicle manufacturer’s specifications. If the boost pressure does not meet specifications, determine the root cause of the low boost pressure (possible exhaust restrictions, wastegate issue, faulty turbocharger, intake leaks, etc.), clear the codes, and retest. If the P2590 is now gone, then the issue was mechanical.
If the P2590 code returns, we will need to test the TBCPS sensor and its associated circuits. With the key off, disconnect the electrical connector from the TBCPS sensor. Connect a black wire from the digital voltmeter to the ground terminal at the TBCPS sensor wiring harness connector. Connect the red wire from the digital voltmeter to the power supply terminal at the TBCPS sensor wiring harness connector. Turn the key to the engine off position. Check the manufacturer’s specifications; the voltmeter should read 12 volts or 5 volts. If not, repair the open in the power or ground wiring or replace the PCM.
If the previous test is successful, we will need to test the signal wire. With the connector still disconnected, move the red voltmeter wire from the power wire terminal to the signal wire terminal. The voltmeter should now read 5 volts. If not, repair the open in the signal wire or replace the PCM.
If all previous tests are successful and you continue to get a P2590, this would most likely indicate a faulty TBCPS sensor, although a faulty PCM cannot be ruled out until the TBCPS sensor has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs need to be programmed or calibrated to the vehicle to be installed correctly.
