What does code P2B74 mean?

Q: What does code P2B74 mean?

Coolant Heater A Control Circuit High. P2B74 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for coolant heater 'A', which is typically a grid heater or block heater used to warm engine coolant for faster cabin heat and reduced cold-start emissions. The PCM commands the heater on or off via a low-side driver, and when the circuit voltage stays above the expected threshold with the command off, or the driver detects an open circuit or short to voltage, it sets this code.

DTC codes / P2Bxx · Hybrid propulsion / P2B74

P2B74Coolant Heater A Control Circuit High

P2B74 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for coolant heater 'A', which is typically a grid heater or block heater used to warm engine coolant for faster cabin heat and reduced cold-start emissions. The PCM commands the heater on or off via a low-side driver, and when the circuit voltage stays above the expected threshold with the command off, or the driver detects an open circuit or short to voltage, it sets this code.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaHybrid propulsion

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.