The control circuit of coolant heater A reports a control circuit/open condition. Auxiliary preheating of the coolant cannot be commanded as expected.
Medium severity. Can I keep driving?Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.
Most likely causes
- Open in heater control wire
- Open heater element
- Pin pushed back out of connector body
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
What each character of P2B72 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- B: Subsystem depends on the code range
- 72: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2B72?
Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.
What causes code P2B72?
The most common causes are: open in heater control wire; open heater element; pin pushed back out of connector body.
Related codes
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.