OBD-II code · Powertrain (generic, extended)

P2C21 Engine Oil Temperature Sensor A/B Correlation

The signals of engine oil temperature sensors A and B do not correlate within the calibrated tolerance. One sensor drifts or installation offset between the two channels.

Is it safe to drive with P2C21?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyOne sensor characteristic drifted
  • PossibleHarness incorrectly swapped between channels

Repair at a glance

Difficulty
Easy
DIY friendly
Often, with basic tools
Typical labour
0.3–2 h
Emissions test
Usually unaffected
Parts involved
Engine Oil Temp Sensor A, Engine Oil Temp Sensor B, Ecm

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.