Polestar 2
EV diagnosis is different: start with 12V stability and charging/thermal plausibility. Many “random” warnings are network or low-voltage cascades, not failed high-voltage components.
Quick triage (5 minutes)
What to capture
- Exact message(s) shown + when it happens (cold start, after charge, during DC fast charge, wet weather)
- 12V battery resting voltage + loaded voltage (headlights/heated screen on)
- Charging context: AC vs DC, charge point, cable, recent software update
- Coolant level and obvious leaks (HV battery/drive unit loops)
- Any recent jump-start, battery replacement, accessories, or water ingress events
What it usually means
- Multiple warnings at once → often 12V or network plausibility, especially after sitting.
- Charge fails immediately → cable/handshake/earth issues, or a charge port/lock concern.
- Reduced performance / turtle → thermal limits, sensor plausibility, or a protection strategy.
- Intermittent faults after rain → connector moisture/water ingress is worth considering early.
Common complaints (and the honest starting point)
- Won’t charge / stops charging: swap variables first (different cable/charger). If AC works but DC doesn’t (or vice versa), treat it as a handshake/thermal/plausibility problem until proven otherwise.
- “Random” warnings after sitting: check 12V health before anything else. EVs still depend on the 12V system to wake modules reliably.
- Heat pump / cabin heat weak: confirm ambient temps and thermal system status; low coolant or airlocks can mimic component failure.
- Intermittent connectivity / infotainment oddities: software and network health can present as vehicle symptoms; document patterns and don’t shotgun parts.
What NOT to do (high-confidence traps)
- Don’t assume a high-voltage battery failure because you saw a “Propulsion system” warning. Start with 12V and reproducible conditions.
- Don’t keep jump-starting repeatedly without addressing the cause of low 12V (battery health, parasitic drain, charging control).
- Don’t attempt HV connector work without correct isolation procedures and competence. Escalate safely.
Checks that pay off early
12V baseline
- Resting voltage after sitting
- Voltage sag under load
- Evidence of poor connections / corrosion
Charging + thermal context
- AC vs DC differences
- Ambient temperature and preconditioning
- Coolant level and obvious leaks
Best workflow: write down the exact warning text, capture when it occurs, and prove the 12V system is stable. If the issue is charging-related, change one variable at a time (charger/cable/location) before concluding the car is at fault.
Safety note: High-voltage EV systems require correct isolation procedures and PPE. This guide focuses on safe, high-value checks (12V, context, plausibility) and when to escalate.