P0A2B

What it means

P0A2B is the generic code for a range or performance fault in the drive motor 'A' temperature sensor 'A' circuit on a hybrid or electric vehicle. The control unit saw a temperature reading that was implausible, stuck, or did not agree with expected values, such as a figure that did not change as it should with load and time, or that differed from other related temperature sensors. The sensor signal is still present, but it is not believable.

Symptoms

• Warning light on, such as the hybrid system or powertrain fault lamp
• Reduced power or the vehicle going into a limited performance mode
• Motor or inverter cooling fan running harder or more often than normal
• Reduced electric assist or reduced regeneration
• Intermittent fault that comes and goes with temperature or vibration
• In some cases the vehicle will not enter ready or drive mode

Possible causes

• Drive motor temperature sensor reading drifted, stuck or faultylikely
• Damaged, chafed or corroded wiring to the sensor, including high resistance in the circuitlikely
• Poor connection at the motor or control unit connector, such as moisture, corrosion or loose pinslikely
• Motor cooling system fault such as low coolant, poor flow or a failed pump causing real temperature to differ from what is expectedpossible
• Fault in the motor or inverter control unit reading the sensor signalrare
• Outdated control unit software where a known fault in the plausibility check is documented by the manufacturerrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting temperatures, speed and load when the code set
2. Check for related codes covering other motor, inverter or coolant temperature sensors, as these point to a shared cause
3. Visually inspect the sensor wiring and connectors for chafing, heat damage, water ingress and corrosion
4. Compare the live motor temperature reading with other temperature data at a cold start; they should be close after the vehicle has been standing
5. Watch the live reading while gently moving the harness to find intermittent faults
6. Check the motor cooling system for coolant level, leaks, flow and pump or fan operation, following the manufacturer's procedure
7. With the high voltage system made safe by a suitably trained person, measure sensor resistance and wiring continuity against the manufacturer's specification
8. Check for technical bulletins or software updates for the specific model, as procedures vary by make and model

How to fix

• Repair or replace damaged wiring and clean or replace faulty connectors
• Replace the drive motor temperature sensor if its readings are out of specification, as the model requires
• Correct cooling system faults such as low coolant, trapped air, or a failed pump, then bleed it correctly
• Update the control unit software only if the manufacturer lists it as a fix for this fault
• Replace or repair the control unit only after the sensor, wiring and cooling system have been proven good

Can I keep driving?

Nearby codes

• P0A2AGenericDrive Motor A Temperature Sensor A Circuit
• P0A2CGenericDrive Motor A Temperature Sensor A Circuit Low