What Does P0C12 Mean?
DTC P0C12 indicates that the Phase V power semiconductor within the drive motor "A" inverter has exceeded its safe operating temperature limit. This is the companion code to P0C11 (Phase U) and P0C13 (Phase W), affecting the middle phase leg. If this code appears in isolation, it points specifically to a Phase V IGBT module degradation. If it appears with P0C11 and P0C13, the inverter cooling system is the more likely root cause.
Safety Warning
Continued operation with an overheating inverter phase risks thermal destruction of the IGBT module, which can result in a short circuit or open circuit of that phase. This can cause sudden motor shutdown or uncontrolled torque output.
Common Causes
28%
Inverter coolant pump failure or reduced flow rate
22%
Degraded or failed Phase V IGBT with increased conduction losses
20%
Blocked or restricted inverter cold plate coolant passages
15%
Extended high-torque operation in hot ambient conditions
15%
Deteriorated thermal paste/pad between Phase V module and heat sink
Diagnostic Steps
1
Step 1: Review freeze-frame data comparing temperatures of all three inverter phases (U, V, W). If only Phase V is elevated, suspect the IGBT module. If all are elevated, suspect cooling.
2
Step 2: Verify inverter coolant pump operation by checking for pump DTCs, measuring coolant flow rate, and confirming the pump is powered and running.
3
Step 3: Check coolant level and condition in the power electronics cooling loop (separate from engine coolant in most hybrids). Look for contamination or air pockets.
4
Step 4: Monitor real-time inverter phase temperatures during a moderate load test. Compare Phase V temperature rise rate against U and W. A significantly faster rise in V alone indicates a component issue.
5
Step 5: If the cooling system is verified functional and only Phase V overheats, the inverter module requires replacement. This is not a field-serviceable component.
Estimated Repair Cost
$500 - $5,500
Parts + labor, varies by vehicle and location
DTC P0C12 indicates that the Phase V power semiconductor within the drive motor "A" inverter has exceeded its safe operating temperature limit. This is the companion code to P0C11 (Phase U) and P0C13 (Phase W), affecting the middle phase leg. If this code appears in isolation, it points specifically...
The most common cause of P0C12 (Drive Motor "A" Inverter Phase V Over Temperature) is: Inverter coolant pump failure or reduced flow rate
Typical repair costs for P0C12 range from $500 to $5,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Continued operation with an overheating inverter phase risks thermal destruction of the IGBT module, which can result in a short circuit or open circuit of that phase. This can cause sudden motor shutdown or uncontrolled torque output.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0C12 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Hybrid/EV Inverter Thermal Management
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
