Faulty coolant pump control module or integrated pump electronics; Open or shorted wire in the pump control circuit (low side to ground); Corroded or loose electrical connector at the pump or control module; Blown fuse or faulty relay supplying power to the pump circuit; Failed coolant pump motor (electrical winding short or open); Poor ground connection for the pump or control module; Software issue in the hybrid control module requiring reprogramming

DTC codes / P0Cxx · Hybrid propulsion / P0C48

P0C48Hybrid/EV Battery Pack Coolant Pump A Control Circuit Low

Q: What does code P0C48 mean?

Hybrid/EV Battery Pack Coolant Pump A Control Circuit Low. P0C48 indicates that the hybrid or electric vehicle battery pack coolant pump control circuit has a low voltage condition, meaning the pump is not receiving the commanded current or voltage. The computer detects this when the control circuit voltage falls below the expected threshold, which can prevent proper cooling of the high-voltage battery.

P0C48 indicates that the hybrid or electric vehicle battery pack coolant pump control circuit has a low voltage condition, meaning the pump is not receiving the commanded current or voltage. The computer detects this when the control circuit voltage falls below the expected threshold, which can prevent proper cooling of the high-voltage battery.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Symptoms you may notice

Illumination of the check engine light or service vehicle soon message
Reduced hybrid system performance or limited power output
Overheating warning for the high-voltage battery, possibly leading to reduced charging or discharging rates
Audible coolant pump not running or abnormal noises from the pump area
Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

Faulty coolant pump control module or integrated pump electronics
Open or shorted wire in the pump control circuit (low side to ground)
Corroded or loose electrical connector at the pump or control module
Blown fuse or faulty relay supplying power to the pump circuit
Failed coolant pump motor (electrical winding short or open)
Poor ground connection for the pump or control module
Software issue in the hybrid control module requiring reprogramming

How to diagnose and fix it

Scan all modules for related codes and record freeze-frame data to understand when the fault occurs
Visually inspect the coolant pump connector and wiring for damage, corrosion, or looseness
Check the fuse and relay that supply power to the coolant pump circuit
Measure resistance and voltage on the control circuit at the pump connector to verify low voltage condition
Perform a bidirectional pump activation test with a scan tool to confirm pump operation
If the circuit tests good, replace the coolant pump and retest the system
If the fault persists, check the hybrid control module for software updates or internal faults

Coolant pump circuit low voltage pitfalls

A low voltage code on the pump control circuit often results from a poor ground connection rather than a failed pump, so always check grounds before replacing parts.
Intermittent faults can be caused by wire chafing where the harness passes near sharp edges or hot components, which may not be visible without wiggling the harness while monitoring live data.
Some vehicles use a pulse-width modulated signal to control pump speed; a low voltage code can set if the signal wire is shorted to ground, which may be caused by a faulty pump or a pinched wire.
Replacing the pump without clearing adaptations or performing a system bleed can lead to air pockets and overheating, mimicking a recurring electrical fault.
The code may set alongside other hybrid battery codes, but P0C48 specifically points to the pump control circuit, not the pump motor circuit, so focus diagnostics on the control side first.

Can I keep driving with P0C48?

It is not advisable to continue driving with this code because the battery pack may not be cooled properly, which can lead to overheating and reduced performance. If you must drive, avoid heavy acceleration and long trips, and monitor for overheating warnings.

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.