Diagnostic Overview
Volvo fault code P0069-64 generally points to manifold pressure/barometric pressure correlation or air-management rationality. The ECM is comparing pressure sensors and seeing values that do not agree with expected engine conditions. Incorrect pressure data can affect turbo control, fueling, EGR operation, and aftertreatment performance.
Likely Causes
Faulty boost pressure sensor; contaminated MAP sensor; barometric pressure sensor issue; intake restriction; boost leak; wiring fault; incorrect sensor data.
What To Check First
Compare MAP/boost/barometric readings key-on engine-off, inspect sensor ports for soot or oil, check wiring, and pressure-test the charge-air system.