Fault codes covered
31-56
This system contains a 670psi high pressure switch as well as a discharge pressure transducer. This fault should not occur as the pressure transducer utilizes a separate high pressure limit at a lower setting. In the case of a fast transient this switch will safely disable system operation. This switch is connected directly to VFD and a break or short in wire harness during high pressure events will also generate fault. The high pressure switch quickly shuts down high voltage to VFD and additional communication faults may occur since the VFD will cease to communicate with PCM. The PCM/VFD will not attempt to resume system operation until discharge pressure has dropped below 425PSIG. Ensure HPS is closed and securely connected to VFD.
Source: ACHPVSR454-02SM troubleshooting pages.