P0A0A: High Voltage System Interlock Circuit A

The high-voltage interlock loop (HVIL) is a low-voltage signal loop routed through every HV connector, the service disconnect and component covers. If it opens, the control module opens the main contactors so no one can touch live parts. P0A0A is the general circuit fault on loop A. Stellantis sets P0A0A-00 on the Jeep Wrangler and Grand Cherokee 4xe when an HV connector is torqued but not fully seated after repair, and on the 2024-2025 Pacifica Hybrid it was traced to battery pack control module software; there the car will not start on either power source. Mercedes logs P0A0A00 in the DC converter of model line 243. CARB counts the HVIL as a safety-only system, so MIL behaviour varies. Low, high, performance and intermittent faults use P0A0B to P0A0E.

Symptoms

• Vehicle will not start or go into ready mode
• Check engine and hybrid system warning on
• High-voltage system switched off while the 12 V system still works

Most likely causes

• HV connector or service disconnect not fully seated after repair
• Spread, bent or corroded interlock pins or damaged connector seals
• Interlock wiring chafed or cut
• Battery pack control module software fault (Chrysler Pacifica Hybrid 2024-2025)

What to check, in order

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

1. Read the codes with a hybrid-compatible scanner and write down the freeze frame data
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Make sure the battery cooling air intake is clean
4. Check the 12 V auxiliary battery, which can also trigger warnings
5. Leave any high-voltage measurements to a specialized repair shop

Good to know

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

What each character of P0A0A means

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

Frequently asked questions

Can I keep driving with code P0A0A?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code P0A0A?

The most common causes are: hV connector or service disconnect not fully seated after repair; spread, bent or corroded interlock pins or damaged connector seals; interlock wiring chafed or cut.

Related codes

• P0A0BHigh Voltage System Interlock Circuit A Performance
• P0A0CHigh Voltage System Interlock Circuit A Low
• P0A0DHigh Voltage System Interlock Circuit A High
• P0A0EHigh Voltage System Interlock Circuit A Intermittent
• P0D15Battery Charging System A High Voltage Interlock Circuit/Open
• P0AA6Hybrid/EV Battery Voltage System Isolation Fault

Sources

• static.nhtsa.gov: MC 11028892 0001
• static.nhtsa.gov: MC 11030214 0001
• static.nhtsa.gov: MC 11026830 0001
• 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.