P055E Oxygen Sensor Control Module System Voltage

Some engines use wide-band or NOx sensors with their own evaluation module that reports over CAN. That module measures its supply; outside its working range it sets P055E, and lambda control and the sensor diagnoses are suspended because no valid values exist. No manufacturer document available to us uses P055E – Ford's diesel monitors the comparable supply of its smart NOx/O2 sensor as P220A/P220B, below 8.5 V or above 16.5 V. CARB requires modules delivering emission-relevant signals to be monitored.

Likely causes

Symptoms

• Check engine light on
• Lambda control in open loop, possibly higher consumption
• Further lambda or communication codes

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.