P0C73: Motor Electronics Coolant Pump A Control Performance
What to do
Check the electronics coolant level and, if there has been any recent coolant work, have the circuit properly bled — air is the commonest cause here and it costs nothing but time. The reservoir is separate from the engine's on most vehicles and easy to overlook entirely.
What this code means
Motor electronics coolant pump A is being commanded correctly and is not achieving what was asked of it.
The circuit codes for this pump are at P0A05; this is the performance variant, and the distinction is the same one the block draws everywhere. A circuit code says the wiring or the driver is wrong. This says the electrics are fine and the coolant is not moving as it should.
So the suspects are hydraulic rather than electrical: air trapped in the circuit after a repair — which is the commonest of them and the one that needs bleeding rather than parts — low coolant, an impeller worn or slipping on its shaft, or a restriction downstream. A pump can spin at exactly the commanded speed and move nothing at all if there is air where the coolant should be, and no electrical test will find it.
Likely causes
Start here
- Air trapped in the inverter cooling circuit · moderate
- Low inverter coolant level · easy
- Faulty inverter coolant pump · moderate
Less common
- Restricted coolant flow or blocked passage · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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- The car — make, model, year and engine. The same fault behaves differently on each.
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