P0C39DC/DC Converter Temperature Sensor A Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0C39 is the plausibility check of DC/DC converter temperature sensor A: its reading lies within the electrical range but does not fit the converter's operating state or a second sensor. FCA uses it on the 2021 Ram 1500 with the 3.6 litre eTorque mild hybrid, where the code is called temperature sensor 1 performance. Bulletin 08-037-21 updates the HCP software and changes this code from a two-trip to a one-trip DTC, so the MIL can come on after a single fault. Sensor B, sensor 2 at Ram, has the matching code P0C3E. CARB requires rationality checks for such inputs. A drifting sensor or poor thermal contact is typical; outright circuit faults are reported as P0C38, P0C3A or P0C3B instead.
- What you may notice
- MIL, after one trip with updated Ram software
- Mild hybrid assist or 12 V supply reduced
- Likely causes
- PossibleOutdated hybrid control software (Ram 1500 eTorque, bulletin 08-037-21)
- PossibleSensor A drifting or with poor thermal contact to the power stage
- RareUneven cooling of the converter making the readings disagree
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €80 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.