What Does P0A30 Mean?
The Drive Motor 'B' Temperature Sensor Circuit code indicates a general malfunction in the temperature monitoring system for the secondary electric drive motor. In dual-motor configurations, Motor B typically powers the rear axle in AWD hybrids or EVs. This sensor provides thermal feedback used by the Motor B controller to manage current limits, cooling demands, and thermal derating. Without reliable temperature data, the controller will restrict Motor B output or disable it entirely to prevent potential thermal damage.
Common Causes
30%
Faulty Motor B temperature sensor (thermistor) with incorrect resistance
25%
Open or high-resistance condition in the temperature sensor wiring harness
20%
Corroded or damaged connector at the Motor B temperature sensor location
15%
Motor B controller internal fault in the temperature input circuit
10%
Sensor wiring routed near high-current phase cables causing signal interference
Diagnostic Steps
1
Read the Motor B temperature sensor value on the scan tool; compare to ambient temperature when cold and to expected operating temperature after driving to assess plausibility.
2
Inspect the Motor B temperature sensor connector for corrosion, heat damage, or moisture; rear-mounted motors are often more exposed to road spray and debris.
3
Disconnect the sensor and measure its resistance with a DVOM at known temperature; compare to the manufacturer's resistance-vs-temperature chart.
4
Check wiring continuity and insulation from the sensor to the Motor B controller; test for shorts to ground, shorts to power, and excessive series resistance.
5
If sensor and wiring are within specification, substitute a known-good resistance value and verify the Motor B controller reads the temperature correctly to rule out a controller input fault.
Estimated Repair Cost
$200 - $900
Parts + labor, varies by vehicle and location
The Drive Motor 'B' Temperature Sensor Circuit code indicates a general malfunction in the temperature monitoring system for the secondary electric drive motor. In dual-motor configurations, Motor B typically powers the rear axle in AWD hybrids or EVs. This sensor provides thermal feedback used by t...
The most common cause of P0A30 (Drive Motor "B" Temperature Sensor Circuit) is: Faulty Motor B temperature sensor (thermistor) with incorrect resistance
Typical repair costs for P0A30 range from $200 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of Motor B temperature monitoring will cause the controller to limit rear motor output, reducing AWD capability and overall performance. Not immediately dangerous but may affect traction in adverse conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0A30 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 Powertrain
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
