P0EB3: A/C Compressor Motor Phase U Current Sensor Circuit Low

P0EB3 means the phase U current signal has fallen below its permitted range. Depending on the sensor design this looks like a large negative current or like no signal at all; either way the controller can no longer trust the U-phase value it needs to drive the motor smoothly. No maker documents P0EB3 publicly. In GM's 2011 Volt, a phase U reading of minus 68 A or lower with the compressor at rest set the older code P0D7B, Type B with MIL after two trips, and a 12 V reset was needed before the test could pass again. Likely causes are a ground short in the sensing path, lost sensor supply or an internal inverter fault. Cooling stays off until the fault clears. Counterpart: P0EB2; the same fault on V and W: P0EB6, P0EB9.

Symptoms

• Air conditioning inoperative
• Fault message after switching the A/C on

Most likely causes

• Phase U sensing path shorted to ground
• Supply to the phase U sensor missing
• Internal fault in the compressor inverter

What to check, in order

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

1. Check the sensor pressure in live data
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Check the relay and connector
4. Have the refrigerant charge and any leaks checked at a repair shop authorized to handle refrigerant

What each character of P0EB3 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• E: Subsystem depends on the code range
• B3: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0EB3?

Yes, you can keep driving. The air conditioning may not work.

What causes code P0EB3?

The most common causes are: phase U sensing path shorted to ground; supply to the phase U sensor missing; internal fault in the compressor inverter.

Related codes

• P0EB2A/C Compressor Motor Phase U Current Sensor Circuit High
• P0EB1A/C Compressor Motor Phase U Current Sensor Circuit
• P0EB4A/C Compressor Motor Phase U Current Sensor Range/Performance
• P0EB6A/C Compressor Motor Phase V Current Sensor Circuit Low
• P0EB9A/C Compressor Motor Phase W Current Sensor Circuit Low
• P0D7BA/C Compressor Motor Phase U Current High

Sources

• gsi.ext.gm.com: 11OBDG01 HYBRID Diagnostics
• 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.