P0B39Motor Electronics Coolant Pump B Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0B39 sets when the control signal of motor electronics coolant pump B is lower than the controller expects, usually a short to ground on the command line or a pump input that pulls the line down. On a low-side switched or PWM line the module sees the voltage stuck low while it commands the pump off. No manufacturer documents P0B39 publicly. Pump B is in service at FCA (Compass and Renegade 4xe, performance code P0C74), and Ford stores the pump A codes P0A06 and P0A07 in the PCM of the 2020 Explorer and Aviator hybrids. CARB requires these inverter cooling outputs to be checked for circuit faults. Open and high faults are P0B38 and P0B3A; running faults use P0C74 and P2D05 ff.
- What you may notice
- MIL and hybrid or coolant warning
- Pump runs permanently or not at all, depending on circuit design
- Power limitation at high load or heat
- Likely causes
- LikelyControl wire shorted to ground, often chafed at brackets
- PossiblePump electronics pulling the control input low
- PossibleCoolant or water in the pump connector
- RareDriver stage in the controlling module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.