P0ADA: Hybrid/EV Battery Positive Contactor Control Circuit Range/Performance

P0ADA describes a positive contactor coil circuit that is electrically present but does not behave plausibly: coil current, voltage or response time outside the expected window, for instance due to high resistance or an unstable PWM hold signal. No manufacturer publicly documents this code; GM, which details the positive contactor driver codes P0AD9, P0ADB and P0ADC with Type B logic and sample counters, does not list P0ADA. CARB 1968.2 requires functional and rationality checks of hybrid output components. It must be separated from the contact-side codes P0AA1 (stuck closed) and P0AA2 (stuck open). Drivers may see intermittent no-start or loss of ready mode.

Symptoms

• Vehicle will not enter ready mode or start
• Hybrid or EV warning light and check engine light
• Charging not possible

Most likely causes

• High resistance in coil wiring or connector (corrosion, fretting)
• Contactor coil degraded or partially shorted
• Low 12 V supply during contactor closing
• Battery controller fault or software

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. Compare the reading with other engine data while varying the engine speed.
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

• It can trigger limp mode.
• It affects emissions.

What each character of P0ADA means

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

Frequently asked questions

Can I keep driving with code P0ADA?

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 P0ADA?

The most common causes are: high resistance in coil wiring or connector (corrosion, fretting); contactor coil degraded or partially shorted; low 12 V supply during contactor closing.

Related codes

• P0AD9Hybrid/EV Battery Positive Contactor Control Circuit/Open
• P0ADBHybrid/EV Battery Positive Contactor Control Circuit Low
• P0ADCHybrid/EV Battery Positive Contactor Control Circuit High
• P0AA1Hybrid/EV Battery Positive Contactor Circuit Stuck Closed
• P0AA2Hybrid/EV Battery Positive Contactor Circuit Stuck Open
• P0ADEHybrid/EV Battery Negative Contactor Control Circuit Range/Performance

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 16OBDG02 Hybrid Diagnostics

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.