P0A35

Code

Generic P — Powertrain

Drive Motor B Over Temperature

Brand: Generic

Type: P — Powertrain

Views: UK: 21 EN: 32 RU: 23

AI status

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Page language: EN

Causes

Actual motor overheating from sustained heavy load or high ambient temperature
Insufficient motor cooling (low coolant level, blocked passages, failed coolant pump, clogged radiator or heat exchanger)
Cooling fan(s) not running or low airflow
Faulty motor temperature sensor (NTC/thermistor) or poor sensor connection
Wiring damage, corrosion, open/short in sensor circuit or connector
High electrical losses in motor (shorted windings, bearing failure, excessive friction)

Symptoms

Hybrid/EV warning lamp and/or specific over-temperature indicator
Reduced propulsion power or limp mode / limited torque
Loss or reduction of regenerative braking
Coolant temperature warning or high coolant temp reading (if applicable)
Unusual smells (hot/overheated electrical insulation) or visible steam/smoke in severe cases
Stored fault(s) and freeze-frame data in hybrid/EV control module

What to check

Scan for P0A35 and any related fault codes; record freeze-frame and live data
Verify vehicle in safe condition (isolate HV system per manufacturer procedures) before any physical inspection
Inspect coolant level and condition in motor/inverter cooling circuit (if liquid-cooled)
Check cooling fan operation, radiator/heat exchanger for blockages, and airflow paths
Visually inspect motor/inverter connectors and wiring for damage, corrosion, or looseness
Monitor drive motor temperature sensor value and compare to ambient and coolant temps in live data

Signal parameters

Drive motor B temperature (°C) — compare to normal operating range and fault threshold
Motor temperature sensor voltage (V) or resistance (Ω) vs expected values
Coolant temperature for motor/inverter (°C) and coolant level
Inverter/controller temperature (°C)
Motor current (A) and torque demand (%) during fault event
Cooling fan speed (rpm) and coolant pump status/duty (%)

Diagnostic algorithm

Safety first: park vehicle, disable high-voltage system per manufacturer procedure before touching high-voltage components.
Retrieve and document all stored codes and freeze-frame data. Clear codes only after documenting and then attempt to reproduce condition with data logging.
Monitor live data during a controlled road or dyno test (if safe) to observe motor B temperature rise profile, motor current, and coolant/inverter temps.
Inspect cooling system: check coolant level/condition, hoses, clamps, radiator/heat exchanger, and look for leaks or blockages. Verify coolant pump operation and coolant flow where accessible.
Verify cooling fans and airflow: run fans at various speeds (via diagnostic tool if available) and confirm operation and adequate airflow through heat exchangers.
Visually inspect motor B and inverter electrical connectors and harness for damage, signs of overheating, corrosion, or loose pins. Repair as needed.
Test motor temperature sensor circuit: back-probe connector, measure sensor voltage/resistance at ambient and after warm-up; compare to expected values and look for open/short conditions.
Check wiring continuity and insulation to ECU/inverter; perform resistance and short-to-ground checks per service manual. Repair wiring faults.
Inspect motor mechanical condition: check for unusual bearing noise, binding, or increased friction that could raise motor temperature. Motor removal or specialist testing may be required.
Check inverter/controller for related faults or overheating that could be causing excessive motor heating. Update software/calibration if manufacturer bulletin applies.
If sensor and cooling system are confirmed good but overheating persists, consider motor winding insulation and internal faults — perform high-voltage insulation testing and consult motor service/replace motor as required.
After repairs, clear codes and perform a monitored verification drive to confirm normal temperature behavior and that P0A35 does not return.

Likely causes

Low or contaminated coolant / air path blocked
Failed coolant pump or radiator fan(s)
Faulty motor temperature sensor or connector
Shorted/grounded motor winding or bearing/mechanical binding increasing heat
Wiring harness damage between motor temperature sensor and ECU/inverter

Fault status

⚠️ Status

Drive motor B temperature exceeded the allowed threshold. ECU has logged an over-temperature fault and may limit motor output or disable regenerative braking until temperature returns to safe levels.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.0-4.0 hours

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