P1406 GMC - EGR Valve Pintle Position Circuit
- Faulty Exhaust Gas Recirculation (EGR) valve
- Carbon blockage of the pintle
The P1406 code means that the EGR valve is 10% of the expected position by the Powertrain Control Module (PCM), usually caused by carbon built up n the EGR valve. Start by cleaning the EGR valve.