Pinpoint Test Ah: U351F
WARNING: This page is about a different car, the 2022 Ford Police Interceptor Utility and 2022 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
- NOTE: The Inverter System Controller (ISC) is referred to as the SOBDMC (Secondary On-Board Diagnostic Control Module C) in the scan tool.
Normal Operation and Fault Conditions
Refer to Electric Powertrain Control - System Operation and Component Description .
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition SOBDMC U351F:00 High Voltage System Interlock Circuit "E" Low: No Sub Type Information This DTC sets when difference is detected between the battery and the PTC heater. Possible Sources
- Wiring, terminals or connectors
- PTC heater
- AH1 REVIEW AND RECORD THE INVERTER SYSTEM CONTROLLER (ISC) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Using a diagnostic scan tool, run the Inverter System Controller (ISC) self-test.
Is DTC U351F present?
Yes GO to AH2 No The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition. - AH2 CHECK THE CABIN COOLANT HEATER CONNECTOR FOR BEING FULLY SEATED
- Ignition OFF.
- Depower the high voltage system. Refer to High Voltage System De-energizing .
- Check that the Cabin Coolant Heater C1851B is connected and fully seated.
Was the connector connected and fully seated?
Yes GO to AH3 No RECONNECT the connector and verify it is fully seated. Repower the high voltage system. Refer to High Voltage System De-energizing . - AH3 INSPECT THE CABIN COOLANT HEATER CONNECTOR
- Ignition OFF.
- Disconnect C1815B .
- Repair:
- Corrosion (install new connector or terminals - clean module pins)
- Damaged or bent pins - install new terminals/pins
- Pushed-out pins - install new pins as necessary
Is a concern present?
Yes INSTALL a new High Voltage Cable assembly. Refer to High Voltage Battery Cables - Hybrid Electric Vehicle (HEV) . CLEAR the Inverter System Controller (ISC) diagnostic trouble codes (DTCs). REPEAT the self-test. No GO to AH4 - AH4 CHECK FOR CORRECT CABIN COOLANT HEATER OPERATION
- Ignition OFF.
- Connect C1815B .
- Repower the high voltage system. Refer to High Voltage System De-energizing .
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new cabin coolant heater. Refer to Cabin Heater Coolant Pump . No The system is operating correctly at this time. The concern may have been caused by module connections. Address the root cause of any connector or pin issues.