CUSTOMER CONCERN Customer states the check-engine light does not illuminate and the scan tool cannot communicate with the ECM. DTCs U0100-211, U0100-530 and U0100-784 are stored in the hybrid ECU. CAUSE Isolating ECM connector E83 terminal 125 restored the 5-volt VC circuit, confirming the fuel-pressure sensor was pulling down the reference circuit. CORRECTION Remove and replace fuel-pressure sensor. Restore VC circuit connection, clear communication DTCs and verify ECM commu