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DTC codes / P2Cxx · Hybrid propulsion / P2C93

P2C93Hybrid/EV Battery Contactor Control Supply Circuit Range/Performance

P2C93 indicates that the hybrid or electric vehicle battery contactor control supply circuit is not performing within its expected range, meaning the voltage or current on the control side of the main battery contactor is outside the manufacturer's specification. The computer monitors this circuit and sets the code when it detects an abnormal condition that could prevent the contactor from opening or closing reliably.

SystemPowertrain
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyProfessional
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the hybrid/EV system warning light or service vehicle soon message
  • The vehicle may fail to enter 'Ready' mode or start at all
  • Intermittent loss of high-voltage power while driving, leading to reduced power or shutdown
  • Audible clicking or no click from the battery pack area when attempting to start
  • Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

  1. Faulty contactor control module or relay driver internal to the battery pack
  2. Damaged or corroded wiring harness or connector at the contactor control circuit
  3. Poor ground connection for the contactor control circuit
  4. Failed battery contactor assembly (coil or control circuit)
  5. Low or unstable 12-volt supply to the control module
  6. Software or calibration issue in the battery energy control module (BECM)

How to diagnose and fix it

  1. Verify the 12-volt battery state of charge and condition, as low voltage can cause false control circuit codes
  2. Inspect the contactor control circuit wiring and connectors for damage, corrosion, or loose pins
  3. Check the control circuit ground connection for cleanliness and tightness
  4. Measure resistance and voltage on the control circuit at the contactor and at the control module to compare with specifications
  5. Test the contactor coil for open or short circuits if accessible
  6. Reprogram or update the battery energy control module (BECM) if a known software calibration exists
  7. Replace the faulty contactor assembly or control module as diagnosed

Contactor control circuit checks that save time

  • A weak 12-volt battery often sets this code because the contactor control module needs a stable supply to operate the coils correctly.
  • Corrosion inside a connector can cause intermittent faults that only appear under vibration or temperature changes, so wiggle-test wiring while monitoring live data.
  • The code can be set by a control circuit that is electrically intact but mechanically sticky, so always verify contactor operation with a bidirectional scan tool.
  • Some vehicles require a high-voltage battery pack service disconnect before testing the contactor circuit, and skipping this step risks serious injury.
  • After repairs, clear the code and perform a full drive cycle including several key-off and key-on events to confirm the fault does not return.

Can I keep driving with P2C93?

Do not continue driving if the vehicle fails to start or shows reduced power, as a contactor fault can cause a sudden loss of high-voltage power. If the warning light is on but the vehicle drives normally, limit driving to a safe distance to a repair facility and avoid high-load conditions.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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