P0EB9: A/C Compressor Motor Phase W Current Sensor Circuit Low

P0EB9 is stored when the phase W current signal drops beneath its lower limit, for instance after the signal wire has made contact with ground or after the sensor has lost its feed. The value is then useless for motor control, and the compressor module shuts the drive down rather than run it on two phases of information. No manufacturer documents P0EB9 publicly. GM's 2011 Volt shows a comparable test: minus 68 A or lower on phase W at standstill set the older code P0D7F, rated Type B with MIL after two trips. Because the sensing sits inside the compressor, repair usually means replacing the compressor assembly once wiring and high-voltage plugs have been checked. High range: P0EB8; plausibility: P0EBA; general W circuit: P0EC0.

Symptoms

• No cooling, compressor silent
• Climate fault indicated

Most likely causes

• Phase W measuring line shorted to ground
• Phase W sensor without supply
• Defect of the W measurement inside the compressor module

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 P0EB9 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• E: Subsystem depends on the code range
• B9: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0EB9?

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

What causes code P0EB9?

The most common causes are: phase W measuring line shorted to ground; phase W sensor without supply; defect of the W measurement inside the compressor module.

Related codes

• P0EB8A/C Compressor Motor Phase W Current Sensor Circuit High
• P0EBAA/C Compressor Motor Phase W Current Sensor Range/Performance
• P0EC0A/C Compressor Motor Phase W Current Sensor Circuit
• P0EB3A/C Compressor Motor Phase U Current Sensor Circuit Low
• P0EB6A/C Compressor Motor Phase V Current Sensor Circuit Low
• P0D7FA/C Compressor Motor Phase W 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.