Diagnostic Overview
CAT fault code 102-00 generally relates to intake manifold pressure or boost pressure being above the expected range. FMI 0 means the value is high at a severe level. The ECM may be seeing actual overboost or a sensor signal that makes boost appear too high. This can lead to derate or protective action because excessive boost can damage engine components. Diagnosis should separate true overboost from a sensor circuit or calibration problem.
Likely Causes
Turbo overboost; sticking wastegate or VGT; restricted exhaust; faulty boost pressure sensor; sensor port blockage; wiring issue; incorrect sensor reading.
What To Check First
Compare boost sensor data to a mechanical gauge if possible, inspect charge-air piping, check turbo control movement, and verify the boost sensor circuit.