OBD-II trouble code
P0C73: Motor Electronics Coolant Pump ‘A’ Control
Application matters: P0C73 concerns control of the motor-electronics coolant pump designated “A”. The label does not identify its location, cooling layout or internal monitoring design. Command, reported operation and actual cooling must be interpreted using the exact vehicle procedure.
The motor-electronics coolant-pump control check reported a fault. The code does not prove a failed pump, a healthy cooling circuit or one specific electrical failure.
Quick facts
- System
- Powertrain
- Category
- Hybrid Propulsion
- Severity
- High severity
- Driving guidance
- Stop safely and arrange diagnosis
- Repair cost range
- Get a vehicle-specific estimate after diagnosis.
- DIY difficulty
- Shop recommended
A code alone cannot establish whether driving is safe. Stop safely for a red brake or oil-pressure warning, overheating, severe misfire, stalling, or impaired braking or steering, and follow the owner's manual. Restraints faults can reduce crash protection even when the vehicle runs normally.
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What does P0C73 mean?
P0C73 identifies a control-related report for the motor-electronics coolant pump named “A”. It differs in subject from P0A93, which names inverter cooling-system performance. That distinction helps select the appropriate diagnostic information; it does not prove that one part of the system is healthy while another has failed.
Control information must be interpreted in context. A pump command, reported operation, speed information and temperature response can answer different questions in the applicable procedure. The absence of a command does not demonstrate a healthy pump or prove that replacing it could never be required. Nor does the control label establish a universal current-sensing driver or make one electrical reading a complete diagnosis.
The July 2014 Hyundai bulletin for the listed Sonata Hybrid vehicles uses pump enable/status, speed and temperature information in a shared procedure for P0C73 and P0A93. Its branches are alternatives: data outside the specified criteria leads to pump replacement, while data meeting them leads to further professional confirmation and replacement if the DTC or condition returns. This is a bounded repair path, not a requirement for both findings on every vehicle.
The installed cooling architecture and required service must be identified before work. An engine gauge alone cannot verify motor-electronics cooling, but the code does not prove a separate coolant loop either. After an established repair, coolant handling or bleeding is performed if the matched procedure requires it; a post-replacement bleed is not evidence that air caused the original control fault.
Hazardous high-voltage energy may remain after the vehicle is switched off. Owners must keep away from high-voltage cables, safety plugs and enclosures. Equipped, trained personnel must use the complete current manufacturer isolation process, required waiting periods and verification that hazardous voltage is absent. A copied voltage value or a partial sequence cannot establish a safe work area.
Possible causes
- A supply, ground, wiring or connector fault established in the identified pump system
- A pump fault supported by the applicable control and response checks
- Inaccurate status or other information used by the installed monitoring strategy
- A control or communication condition identified by the full vehicle diagnosis
- A controller or calibration fault confirmed by the manufacturer’s test path
Symptoms
- A hybrid-system or check-engine warning
- A stop-driving message or alarm on an affected vehicle
- Reduced, unavailable or abnormal propulsion if the current fault affects operation
- Additional cooling-performance or communication codes, if recorded
- A stored control fault without an obvious current symptom
Diagnostic steps
Save the full scan report, code status, and available freeze-frame data before clearing anything. Confirm the reporting module, any failure-type suffix, and the procedure for the exact vehicle. The steps below are an overview; use manufacturer specifications and safety procedures for testing.
- 1.If the vehicle displays a hybrid stop-driving warning, pull over safely, follow the handbook’s shutdown guidance and obtain assistance. Do not continue solely to test whether cooling recovers.
- 2.Have every relevant module scanned and preserve complete DTCs, status and event information before clearing. Report the observed warnings and any recent cooling or electrical work.
- 3.Identify the actual A-designated pump, its control strategy and the applicable diagnostic procedure. Do not select a pump or infer a separate reservoir from the generic title.
- 4.Have a qualified technician interpret the required command, reported operation and actual response together. A missing command, apparent pump noise or one data value is not a component-health verdict.
- 5.Use the vehicle-specific path to assess relevant circuit, communication, pump and cooling information. Do not substitute a generic current-draw test, force the pump to run or make owner circuit measurements.
- 6.For a matching Sonata Hybrid, apply the Hyundai data and confirmation alternatives accurately. Keep its operating sequence with qualified service personnel rather than using it as an owner drive-cycle recipe.
- 7.Any protected access requires the complete manufacturer high-voltage isolation, waiting and verification process. Complete only the diagnosed repair and its required coolant service, setup and confirmation.
Repair cost
Get a vehicle-specific estimate after diagnosis.
A trouble code alone does not price the repair. Ask the shop to identify the confirmed fault and itemize diagnosis, parts, labor, programming or calibration, and taxes.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with hybrid / ev cooling pump or water pump replacement, if diagnosed preselected. Adjust labor rate and vehicle category to fit your situation.
Related repairs
These links are planning examples; the code does not confirm that any listed part has failed.
DIY vs shop
A qualified shop is recommended because this can involve a high-voltage traction system that stays live with the car switched off and requires documented shutdown procedures, in-date insulating gloves, and specific training. Ask the technician what testing confirmed the repair.