OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P2D40

Hybrid/EV Battery Cooling System C Performance

The hybrid battery cooling system C does not maintain target temperatures under load. Coolant flow, radiator fouling, or pump output reduced on this branch.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / numberD / 40

Possible causes

  • Radiator fins fouled - reduced heat rejection high
  • Pump output degraded with age medium
  • Pack cell imbalance approaching service threshold low

Symptoms

  • EV/hybrid system warning light on
  • Reduced power output or limp mode
  • Charging may fail or be slowed
  • Reduced electric range

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 300–2000 €
  • Estimated time: 2–7 h
  • Component: hybrid battery cooling system c
  • Component: battery pack coolant loop
  • MIL / check engine light
  • limp mode possible

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication