X18 - Check HFC Circuit For Short to Power

- Key "OFF".

- Breakout box installed, Powertrain Control Module (PCM) disconnected.

- Constant Control Relay Module (CCRM) disconnected.

- Key "ON".

- Measure voltage between the High Fan Control (HFC) test pin at the breakout box and the battery negative post.

- Is voltage less than 1.0 volt?

Yes -- Key "OFF". Go to X19. X19 - Check HFC Circuit For Shorts To Ground

No -- Service short to power. Remove breakout box. Reconnect all components. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

If Diagnostic Trouble Code (DTC) 563 is still present, replace PCM.