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Powertrain Source reviewed Lights the check engine lamp

P0BAD: Hybrid/EV Battery Voltage Sense W Circuit Intermittent/Erratic

Standardized SAE J2012 code · P0Bxx — Hybrid and electric propulsion

Safety-critical system. Faults in airbags, brakes, steering or high-voltage components can put people at risk. Follow the manufacturer's service information and safety procedures, or have the vehicle checked by a qualified workshop.

What does P0BAD mean?

P0BAD is reserved for a W signal that drops out or jumps for short moments instead of failing outright. No manufacturer documents the code publicly. GM monitors channel W in several programmes, from the 2011 Volt to the eAssist and the 2019 tables, but only through P0BA9 to P0BAC; none of them contains an intermittent test. The slot exists because J2012 gives every sense channel five codes and CARB 1968.2 requires the battery voltage sensors of a hybrid energy storage system to be monitored with fault codes that point to the smallest replaceable part. If a vehicle did store it, the usual suspects would be a crimp or connector that loses contact under vibration or with temperature changes.

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

Symptoms

  • Warning lamp that comes and goes
  • Occasional short power reduction

Common causes

  • High Loose or fretting connector pin on lead W
  • Medium Crimp on lead W opening with temperature changes
  • Low Cracked solder joint on the monitoring board input W

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

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