P0E5C DC/DC Converter Temperature Sensor C Circuit Intermittent/Erratic

P0E5C flags a sensor C signal that changes faster than the part it watches could heat or cool. A converter inductor or heat sink has thermal mass, so a jump of many degrees within a few milliseconds points to a contact problem in the circuit, not to the converter itself. No manufacturer documents P0E5C publicly. The sensor is known from Ford, where sensor C watches the boost converter inductor and is checked only through P0E59 with fixed voltage and temperature limits; an erratic check is not described there. CARB requires hybrid input components to be monitored for circuit faults. Typical causes are a loose terminal, vibration damage or moisture at the converter connector. The fault may come and go between drives, so a wiggle test with live data helps more than a static measurement.

Likely causes

Symptoms

• Hybrid warning that comes and goes
• Short episodes of reduced electric power

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, fordservicecontent.com.