Damaged or corroded wiring harness at the coolant pump connector, causing a short to ground; Failed coolant pump B, where the internal motor or control electronics have shorted; Poor electrical connection at the pump or control module due to loose pins or water intrusion; Faulty control module driver circuit that incorrectly reports a low condition; Chafed wire rubbing against a metal surface, creating a short to ground; Coolant contamination or debris causing pump seizure and subsequent circuit overload

DTC codes / P2Exx · Hybrid propulsion / P2E43

P2E43Hybrid/EV Electronics Coolant Pump B Control Circuit Low

Q: What does code P2E43 mean?

Hybrid/EV Electronics Coolant Pump B Control Circuit Low. P2E43 indicates that the hybrid or electric vehicle electronics coolant pump B control circuit is reporting a low voltage condition, meaning the control module has detected a short to ground or an abnormally low signal on the pump's control wire. This pump circulates coolant through the power electronics, and a low circuit can prevent proper cooling of components such as the inverter or onboard charger.

P2E43 indicates that the hybrid or electric vehicle electronics coolant pump B control circuit is reporting a low voltage condition, meaning the control module has detected a short to ground or an abnormally low signal on the pump's control wire. This pump circulates coolant through the power electronics, and a low circuit can prevent proper cooling of components such as the inverter or onboard charger.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Symptoms you may notice

Illumination of the hybrid system warning light or service vehicle soon message
Often no symptoms besides the warning light, especially if the pump is still partially functional
Reduced hybrid system performance or a forced limp mode in some vehicles
Possible overheating warning for the power electronics, leading to shutdown
In rare cases, a no-start condition if the control module inhibits operation to protect the electronics
Audible pump noise or lack of pump operation when the vehicle is in ready mode

Common causes, most likely first

Damaged or corroded wiring harness at the coolant pump connector, causing a short to ground
Failed coolant pump B, where the internal motor or control electronics have shorted
Poor electrical connection at the pump or control module due to loose pins or water intrusion
Faulty control module driver circuit that incorrectly reports a low condition
Chafed wire rubbing against a metal surface, creating a short to ground
Coolant contamination or debris causing pump seizure and subsequent circuit overload

How to diagnose and fix it

Inspect the coolant pump B connector and wiring for corrosion, loose pins, or signs of coolant intrusion
Disconnect the pump and measure resistance from the control wire to ground to check for a short
Test the pump motor directly with a known-good power source to verify it spins freely and draws normal current
Check the control module connector for tightness and inspect the harness for chafing or damage along its routing
If wiring and pump test good, substitute a known-good pump to see if the code clears
Clear the code and perform a road test with the scan tool monitoring pump control voltage and current
If the code persists after all checks, diagnose the control module driver circuit or replace the module as needed

Before you replace the coolant pump

A low control circuit code often results from a simple chafed wire or corroded connector, so always perform a visual inspection and continuity test before condemning the pump.
The pump may still run intermittently, so a lack of obvious overheating does not rule out a circuit fault; the code can set only under specific key-on or self-test conditions.
Some vehicles use a pulse-width modulated control signal, and a low voltage can be caused by a failed driver in the control module rather than the pump itself.
Coolant leaks from the pump seal can wick into the connector and create a short, so check for dried coolant residue around the pump housing.
After repairs, the control module may require a relearn or adaptation procedure for the new pump to avoid a repeat code.

Can I keep driving with P2E43?

It is generally safe to drive short distances to a repair shop, but avoid sustained high-load driving or towing until the fault is fixed, as power electronics overheating can lead to a sudden shutdown or reduced power.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.