The control module detected that the signal in the Coolant Heater B Control circuit stayed below the expected operating range.
TuningBot DTC Database · v4.37.15
P2B77 Coolant Heater B Control Circuit Low
Generic (OBD-II) interpretation in the TuningBot DTC database.
What P2B77 means
Related and nearby codes
How to read P2B77
Powertrain: engine, transmission and driveline systems.
Generic SAE-standard code: same meaning on every make.
Specific fault index within the subsystem.
Frequently asked questions about P2B77
What does P2B77 mean?
Coolant Heater B Control Circuit Low. The control module detected that the signal in the Coolant Heater B Control circuit stayed below the expected operating range.
Is P2B77 generic or manufacturer-specific?
P2B77 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
Can TuningBot remove P2B77 at file level?
If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry. Checksum correction is not included: it is a separate, optional service. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.
Other file services
Understand the system behind this code: Diagnostic Strategy and DTC Logic
