Fault codes covered
24-58
The PCM supplies 5V DC to the VFD either directly through the circuit board (27VPA) or through the communication harness to the power low voltage ICs (pin 4 of 6 pin wire harness). If this voltage is interrupted the VFD will cease to communicate with the PCM. The PCM will continue to operate for a short period of time in case this interruption is intermittent, but if the voltage is not restored the system will shut down and declare code 24-58. The fault will clear once 5V DC is restored to the VFD. The 5V DC from the PCM is also shared with the 5V DC power pressure transducers.
26VNA/27VNA Models
When code 24-58 is active, disconnect PCM to VFD communication harness and measure voltage between pins 3 (GND) and pin 4 (+5V DC) at the VFD connection end. If voltage is present, reconnect harness, power cycle, and check if fault is still present. If so, VFD will require replacement. If voltage is not present at VFD end of harness, check for voltage at the PCM header. If voltage is not present there, disconnect all other sensors from PCM until fault is cleared. Whichever sensor is disconnected that makes fault disappear should be inspected for damage, likely a short exists in the harness. Once all sensors are disconnected and fault is present, confirm – 5VDC is not present on PCM board; if not then replace PCM.
27VPA Models
When code 24-58 is active disconnect all other sensors from PCM until fault is cleared. Whichever sensor is disconnected that makes fault disappear should be inspected for damage, likely a short exists in the harness. Once all sensors are disconnected and fault is present, then replace PCM.
Source: ACHPVSR454-02SM troubleshooting pages.