P0A35 — Drive Motor “B” Over Temperature #

Note: The wording for DTC P0A35 may vary depending on the vehicle manufacturer (OEM).

• Drive Motor “B” Over Temperature (Toyota, Lexus, Honda, Ford)
• Hybrid/EV Drive Motor 2 Over Temperature (General Motors, Chevrolet, Nissan)
• Traction Motor “B” Overheat Detected (Hyundai, Kia, BMW)
• Electric Drive Unit B Temperature Too High (Volkswagen, Audi)

Summary of Code P0A35 #

DTC P0A35 is an OBD-II trouble code that signals the drive motor “B”—a key electric propulsion motor, typically found in hybrid and electric vehicles (EVs)—is operating at a temperature above its safe threshold. This condition is detected by the powertrain control module (PCM) or hybrid control module when the built-in temperature sensor for motor “B” reports values outside manufacturer-specified limits. The code is designed to protect the motor from damage due to overheating, which could result from heavy load, cooling system issues, or internal faults. Prompt diagnosis and repair are essential to avoid more severe (and expensive) system damage. This alert may cause the vehicle to enter reduced power mode to limit further risk.

Common Symptoms for DTC P0A35 #

Recognizing the signs associated with code P0A35 can help prevent further harm to your vehicle’s propulsion system. Most symptoms relate to the vehicle’s performance and warning indicators:

• Check Engine Light (CEL) or Hybrid System Warning illuminated
• Noticeable loss of power or reduced acceleration (“limp mode”)
• Overheating warning messages on the dashboard
• Unusual fan noise or high-speed cooling fan operation
• Potential shutdown of electric drive, reverting to gasoline engine if available
• In rare cases, burning smell or unusual noises from the electric drive unit

Probable Causes for Code P0A35 #

There are several reasons why the drive motor “B” may overheat, and some are more common than others. The most probable causes, in descending order of frequency, include:

1. Cooling system malfunction (low coolant, faulty pump, blocked passages)
2. Extreme driving conditions (sustained high load, towing, steep grades)
3. Defective temperature sensor in drive motor “B”
4. Internal fault within the drive motor (winding short, insulation breakdown)
5. Electrical connector or wiring issue (corrosion, loose pins, damage)
6. Control module calibration error or software bug (less common)

Step-by-Step Diagnostic for P0A35 #

Diagnosing P0A35 requires a methodical approach and some basic tools. Here’s a proven step-by-step outline:

1. Connect a professional-grade scan tool to confirm P0A35 and check for related codes (especially hybrid/EV or cooling system codes).
2. Record freeze-frame data to see under what conditions the code was triggered (speed, temperature, load).
3. Inspect the coolant level and condition for the drive motor cooling circuit; top up or replace as needed.
4. Check operation of the electric water pump and cooling fans—activate them via scan tool if possible.
5. Visually inspect all relevant wiring and connectors for signs of damage, corrosion, or loose connections.
6. Use the scan tool or a multimeter to monitor the drive motor “B” temperature sensor readings versus ambient temperature—look for obvious discrepancies.
7. If equipped, use an infrared thermometer to independently verify the actual motor case temperature.
8. If the cooling system and wiring check out, suspect an internal motor fault; advanced diagnosis may require OEM-level tools or specialist assistance.

Repair Options for Code P0A35 #

Based on the root cause determined during diagnosis, several repair actions may restore proper operation. Here are the most common repairs tied to each likely cause:

• Low or contaminated coolant: Drain, flush, and refill the drive motor cooling system with OEM-specified coolant.
• Faulty cooling pump or fans: Replace the defective electric pump or cooling fan assembly.
• Damaged wiring or connectors: Repair or replace any corroded, broken, or loose connectors and wiring harnesses.
• Defective temperature sensor: Replace the drive motor “B” temperature sensor as per OEM procedure.
• Internal drive motor fault: Rebuild or replace the drive motor unit (may require hybrid/EV specialist).
• Software update needed: Reprogram the hybrid/EV control module with the latest OEM calibration.

Is It Safe to Drive with Code P0A35? #

Driving with DTC P0A35 is not recommended. Overheating the drive motor can cause permanent damage to high-voltage components, resulting in extremely costly repairs. Most modern hybrids and EVs will enter “limp mode” or even shut down propulsion as a safety measure, severely limiting your ability to drive. If you see this code, it’s best to have the vehicle inspected and repaired as soon as possible. If the car displays warning messages or loses power while driving, stop in a safe location and seek professional assistance.

Vehicles Most Commonly Affected by P0A35 #

Code P0A35 is most often reported on modern hybrids and electric vehicles equipped with dual or multiple drive motors. The following models and manufacturers are more likely to experience this code:

• Toyota Prius, RAV4 Hybrid, Highlander Hybrid
• Lexus RX, ES, and NX Hybrid models
• Chevrolet Volt, Bolt EV
• Ford Fusion Hybrid, C-Max Energi, Escape Hybrid
• Hyundai Ioniq Hybrid/EV, Kona EV
• Kia Niro Hybrid/EV
• Nissan Leaf (with dual-motor configs)
• BMW i3, i8, and plug-in hybrid models
• Volkswagen e-Golf, Audi e-tron

Common Mistakes & Best Practices with P0A35 #

Mistakes in diagnosing P0A35 can lead to unnecessary part replacements or missed root causes. Here are some pitfalls to avoid and best practices to ensure a thorough repair:

• Skipping the cooling system inspection and jumping straight to motor replacement
• Neglecting to check for updated control module software or OEM technical bulletins
• Overlooking connector and wiring faults—these are a frequent source of intermittent temperature readings
• Failing to use OEM-specified coolant or mixing incompatible types
• Best practice: Always record and analyze freeze-frame data; it provides vital clues to the context of overheating
• Best practice: Clear codes after repair and perform a thorough road test to ensure the issue is resolved

Express FAQ for Code P0A35 #

Still have questions? Here are quick answers to the most common concerns:

• Q: Can I reset code P0A35 and keep driving?
  A: Clearing the code without addressing the cause will likely result in the code returning, and continued driving may risk permanent damage.
• Q: Is P0A35 covered by warranty?
  A: If your vehicle is still under the hybrid/EV powertrain warranty, repairs related to motor cooling or the drive motor itself are typically covered. Check with your OEM dealer for specifics.
• Q: Can a simple coolant top-up fix this code?
  A: In some cases, yes. But always check for leaks or pump failures, as low coolant is usually a symptom of a larger issue.