P05C2 Engine Coolant Pressure Sensor Circuit

An engine coolant pressure sensor (5 V reference, ratiometric signal) measures pressure in the cooling circuit; in a sealed circuit pressure rises with temperature, so deviations reveal leaks or a loose cap – described in Navistar and GE patents for commercial and rail engines. No manufacturer document available to us uses P05C2–P05C6 for passenger cars; CARB requires input components to be checked for circuit faults, range and plausibility. P05C2 is the general circuit fault – signal, reference or ground open, or no communication from a digital sensor. Leak detection is then unavailable.

Likely causes

Symptoms

• Check engine light or warning (depending on the maker)
• Coolant pressure or leak warning unavailable
• Usually no change in driving

Repair estimate

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

Parts involved

Related codes

References: law.cornell.edu, patents.google.com, patents.google.com.