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

What does P0ADA mean?

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.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

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

Common causes

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

Likelihood is a general estimate across vehicles; your make and model may differ.