P0A07: Motor Electronics Coolant Pump A Control Circuit High

The module measures a voltage on the pump A control line that is higher than the commanded state allows, typically because the line touches a supply wire or the pump input has failed internally. The pump in the inverter and motor cooling loop may then be stuck on or never receive a valid command. No manufacturer documents P0A07 publicly. GM's Volt flags a short to voltage on its equivalent pump line as P0CE9, with 16 failures in 20 samples at 250 ms and a two-trip MIL. CARB requires inverter cooling outputs to be monitored for such circuit faults; Toyota patents describe pump speed and coolant flow checks for the same loop. P0A05 and P0A06 cover open and short to ground.

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.

Symptoms

Hybrid system or check engine light
Pump running all the time, even with the vehicle off
Possible power limitation if cooling cannot be confirmed

Most likely causes

Control wire shorted to a battery or ignition supply wire
Pump control electronics failed, pulling the input high
Output driver in the control module damaged

What to check, in order

Start with the simplest. You can tick off each step.

With the engine cold, check the coolant level; never do this when the system is hot
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Check the actual temperature in live data
Make sure the fan comes on when it should
Check the thermostat and connector
Measure the sensor and replace it if its readings do not make sense

Good to know

Repair difficulty: medium
It can trigger limp mode.
It affects emissions.

What each character of P0A07 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
A: Hybrid or air and fuel
07: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A07?

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 P0A07?

The most common causes are: control wire shorted to a battery or ignition supply wire; pump control electronics failed, pulling the input high; output driver in the control module damaged.

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.