What Does P0C16 Mean?
DTC P0C16 indicates that the Phase W power semiconductor in the drive motor "B" inverter has exceeded its maximum safe operating temperature. This completes the set of per-phase temperature monitoring codes for inverter "B". The diagnostic approach is identical to P0C14 and P0C15: determine whether the over-temperature is isolated to Phase W (indicating a degraded IGBT) or shared across all phases (indicating a cooling system issue).
Safety Warning
Thermal runaway of an IGBT module is a fire risk. Loss of Phase W control can cause motor vibration, torque pulsation, and eventual complete motor "B" shutdown. Do not ignore persistent over-temperature codes.
Common Causes
28%
Cooling system failure affecting inverter "B" heat rejection
22%
Partially degraded Phase W IGBT with increased thermal losses
20%
Restricted coolant flow through the inverter "B" cold plate
15%
Prolonged high-power operation in hot weather conditions
15%
Thermal interface degradation at Phase W module location
Diagnostic Steps
1
Step 1: Review freeze-frame data for all motor "B" inverter phase temperatures. Cross-reference with P0C14 and P0C15 — all three present means cooling issue; only P0C16 means Phase W IGBT.
2
Step 2: Check the power electronics cooling system: pump operation, coolant level, flow rate, radiator fan, and thermostat function for the inverter cooling loop.
3
Step 3: Perform infrared thermal imaging of the inverter "B" housing during operation to identify whether heating is localized to the Phase W area or distributed evenly.
4
Step 4: Inspect coolant condition and service interval. Degraded coolant loses thermal capacity and may deposit material in the cold plate passages.
5
Step 5: If Phase W IGBT degradation is confirmed, the entire inverter "B" module must be replaced and the cooling system flushed.
Estimated Repair Cost
$500 - $5,500
Parts + labor, varies by vehicle and location
DTC P0C16 indicates that the Phase W power semiconductor in the drive motor "B" inverter has exceeded its maximum safe operating temperature. This completes the set of per-phase temperature monitoring codes for inverter "B". The diagnostic approach is identical to P0C14 and P0C15: determine whether ...
The most common cause of P0C16 (Drive Motor "B" Inverter Phase W Over Temperature) is: Cooling system failure affecting inverter "B" heat rejection
Typical repair costs for P0C16 range from $500 to $5,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Thermal runaway of an IGBT module is a fire risk. Loss of Phase W control can cause motor vibration, torque pulsation, and eventual complete motor "B" shutdown. Do not ignore persistent over-temperature codes.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0C16 to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid/EV Inverter Thermal Management
Difficulty
Type
Generic (SAE)
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