P0A20: Motor Torque Sensor Circuit High

This code covers the upper electrical limit of a torque sensor fitted to the traction motor shaft, for example the magnetostrictive design inside a hollow output shaft described in a Honda patent. The control unit sets P0A20 when the sensor voltage remains above the valid range for a calibrated time, which points to a short to the supply voltage, an open ground return or a sensor output stuck high. No manufacturer documents P0A20 publicly; CARB requires an approved drive motor monitor. Siblings: P0A19 low, P0A18 implausible torque, P0A21 intermittent, P0A17 general circuit. Expect a hybrid warning and limited electric torque.

Symptoms

• Hybrid system warning light
• Electric drive torque limited
• Reduced acceleration in electric mode

Most likely causes

• Signal line shorted to sensor supply or battery voltage
• Open sensor ground return
• Sensor electronics output stuck high

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the fluid level and condition
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Read the input and output speed in live data
4. Check the connector and wiring
5. Check for other related engine codes
6. Consult the manufacturer's procedure for the transmission

Good to know

• Repair difficulty: hard
• It can trigger limp mode.
• It affects emissions.

What each character of P0A20 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• A: Hybrid or air and fuel
• 20: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A20?

Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.

What causes code P0A20?

The most common causes are: signal line shorted to sensor supply or battery voltage; open sensor ground return; sensor electronics output stuck high.

Related codes

• P0A17Motor Torque Sensor Circuit
• P0A18Motor Torque Sensor Circuit Range/Performance
• P0A19Motor Torque Sensor Circuit Low
• P0A21Motor Torque Sensor Circuit Intermittent

Sources

• patents.google.com: en
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.