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DTC codes / P2Cxx · Hybrid propulsion / P2C92

P2C92Hybrid/EV Battery Contactor Control Supply Circuit/Open

P2C92 indicates that the hybrid or electric vehicle battery pack's main contactor control supply circuit has an open circuit, meaning the battery energy control module cannot detect the expected voltage or continuity on that control path. The computer sets this code when the contactor control supply circuit fails to provide the necessary power or ground to the contactor coil driver, preventing the high-voltage contactors from closing and isolating the battery pack.

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

Symptoms you may notice

  • The hybrid or EV system warning light illuminates, and the vehicle may refuse to start or enter 'Ready' mode.
  • A message such as 'High-Voltage Battery Fault' or 'Service Hybrid System' appears on the dashboard.
  • The vehicle may run in reduced power mode or shut down unexpectedly while driving.
  • The high-voltage contactors may not close, resulting in no power delivery from the battery pack.
  • Often no symptoms besides the warning light, especially if the open circuit is intermittent or only affects a redundant control path.

Common causes, most likely first

  1. A broken or corroded wire in the contactor control supply circuit, commonly at a connector or splice point.
  2. A failed contactor control relay or fuse that supplies power to the contactor coil driver circuit.
  3. An open circuit inside the battery energy control module (BECM) or contactor driver module.
  4. A faulty high-voltage contactor assembly where the control coil has an open winding.
  5. Loose or damaged pins in the connector at the BECM or contactor assembly.
  6. Water intrusion or corrosion in the control circuit harness, especially in underbody or battery pack areas.

How to diagnose and fix it

  1. Retrieve all stored codes and freeze-frame data with a scan tool capable of reading hybrid/EV-specific modules, then clear codes and verify whether P2C92 returns immediately.
  2. Visually inspect the contactor control supply circuit wiring and connectors for chafing, corrosion, loose pins, or signs of water intrusion.
  3. Check the contactor control supply fuse and relay, testing for power and ground at the relay socket and replacing any failed components.
  4. Measure resistance and voltage drop on the control supply wire from the BECM to the contactor assembly, repairing any open or high-resistance section.
  5. Test the contactor coil resistance at the contactor assembly connector and compare to the manufacturer's specification to rule out an open coil.
  6. If the circuit and contactor test good, perform a pin-fit and terminal tension check at the BECM connector, then substitute a known-good BECM only after confirming all external circuits are intact.
  7. After repair, clear codes and perform a high-voltage system enable test to confirm the contactors close and the code does not reset.

Before you replace the battery pack

  • A loose or backed-out terminal in the BECM connector is a frequent cause of this code that visual inspection alone can miss, so always perform a pin drag test on the control supply circuit.
  • The code can be set by a failing contactor control relay that still clicks audibly, so test the relay under load rather than trusting the click sound.
  • Intermittent opens often appear only when the harness is flexed or the vehicle is driven over rough roads, so wiggle-test the harness while monitoring live data for the contactor control supply voltage.
  • Some vehicles use a redundant contactor control supply circuit, and a single open may not prevent the contactors from closing, leading to a no-symptom code that still requires repair for safety compliance.
  • Corrosion inside the battery pack enclosure from a blocked drain or damaged seal can attack the control circuit wiring, so inspect the pack interior for moisture before condemning the BECM.

Can I keep driving with P2C92?

Do not continue driving with this code, because the high-voltage contactors may fail to close or may open unexpectedly, leaving the vehicle without propulsion and creating a safety risk. Have the vehicle towed to a qualified hybrid/EV service facility for diagnosis and repair.

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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