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P1A31 fault code: what it means

P1A31: Outlander PHEV: drive battery cell voltage high (battery management unit). Can bring on the RBS warning.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

  1. drive battery cells out of balance (not charged to full often enough)
  2. aged drive battery with weak cells
  3. very cold drive battery
  4. faulty cell monitoring unit or loose connector in the pack

P1A31 by make

Mitsubishi

Outlander PHEV: drive battery cell voltage high (battery management unit). Can bring on the RBS warning.

Usual causes: drive battery cells out of balance (not charged to full often enough); aged drive battery with weak cells; very cold drive battery; faulty cell monitoring unit or loose connector in the pack

Not sure what P1A31 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.