P055E code meaning
Oxygen Sensor Control Module System Voltage
Powertrain system Generic code P05xx codes Check engine light
What P055E means
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.
P055E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P055E
- Check engine light on
- Lambda control in open loop, possibly higher consumption
- Further lambda or communication codes
Common causes of P055E
- Most likelyFuse, relay or supply line to the sensor module
- PossiblePoor module ground
- PossibleBattery or alternator (under- or overvoltage)
- Less likelySensor module faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor control moduleModule power supplyModule ground
What each part of P055E means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 5E | The exact fault in that area. |
What to do next
- Note P055E and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P055E
What does P055E mean?
P055E means "Oxygen Sensor Control Module System Voltage". Some engines use wide-band or NOx sensors with their own evaluation module that reports over CAN. It is a generic code, so it means the same on every make.
Is it safe to drive with P055E?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P055E fail an emissions test?
Yes, it can. P055E is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P055E to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P055E clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.