P00B7Engine Coolant Flow Low/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- When the engine is hot, the thermostat should be open and coolant should flow through the radiator. P00B7 is set when the engine coolant temperature is very high (above about 117 to 119 °C in documented cases) while the radiator side stays much colder, so too little coolant flows through the radiator. The usual cause is a thermostat stuck closed; low coolant, air in the system, a pump that delivers too little or a blocked radiator have the same effect. If the temperature keeps rising, stop driving to avoid engine damage.
- What you may notice
- Check engine light on
- Coolant warning light
- High engine temperature up to overheating
- Weak or fluctuating cabin heating
- Likely causes
- LikelyThermostat stuck closed
- LikelyLow coolant level or air in the cooling system
- PossibleCoolant pump delivering too little (impeller, drive; known cases on some engines)
- PossibleRadiator or hoses blocked
- RareOne of the temperature sensors reading wrong
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €100 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.