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DTC codes / P2Exx · Hybrid propulsion / P2E30

P2E30Battery Charger B Module Supply Voltage Low

P2E30 indicates that the powertrain control module (PCM) has detected a low supply voltage at the battery charger control module B, which is typically part of the high-voltage battery charging system on electrified vehicles. The PCM monitors the voltage feed to this module and sets the code when the signal falls below the expected threshold for a calibrated time, indicating a power supply problem rather than a charging performance issue.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light or service vehicle soon message
  • Often no symptoms besides the warning light, especially if the low voltage is intermittent
  • Reduced or disabled high-voltage charging, leading to longer charge times or inability to charge
  • A warning message on the dash indicating a charging system fault or limited power
  • Possible no-start condition if the low-voltage battery is also affected
  • In some cases, the vehicle may enter a reduced power mode or fail to start

Common causes, most likely first

  1. Blown fuse or fusible link supplying power to the battery charger control module B
  2. Corroded, loose, or damaged wiring or connector at the module or in the supply circuit
  3. High resistance in the power supply circuit due to chafed wires or poor grounds
  4. Faulty battery charger control module B internal power supply
  5. Low-voltage battery weak or failing, causing system voltage to drop under load
  6. Charging system fault from the DC-DC converter not maintaining proper voltage
  7. PCM or control module software error causing false detection

How to diagnose and fix it

  1. Check for any related technical service bulletins (TSBs) or software updates for the PCM and charger module
  2. Inspect and test the fuse and relay that supply power to the battery charger control module B
  3. Perform a voltage drop test on the power and ground circuits at the module connector
  4. Check the low-voltage battery state of charge and load test it; recharge or replace if weak
  5. Inspect connectors for corrosion, tightness, and pin fit; repair or replace as needed
  6. If all circuits test good, substitute a known-good module or follow manufacturer diagnostics to test the charger module
  7. Clear codes and verify the repair by test-driving and monitoring live data for the supply voltage parameter

Don't overlook the low-voltage battery

  • A weak or failing 12-volt battery is a common root cause because it drags down the supply voltage to the charger module during startup or high load.
  • The code can set intermittently due to a loose ground connection that only acts up under vibration or temperature changes.
  • A blown fuse may be a symptom of a shorted module or wiring, so replacing the fuse without finding the short often leads to a repeat failure.
  • Some vehicles use a dedicated voltage supply line that passes through a junction box; corrosion inside the box is easily missed during visual inspection.
  • The PCM may set this code even when the high-voltage battery charges normally, so don't assume the charger itself is faulty without testing the supply circuit.

Can I keep driving with P2E30?

If the vehicle drives normally and only the warning light is on, you can usually continue driving, but avoid relying on high-voltage charging and schedule service soon. If the vehicle fails to start or shows a reduced power message, stop driving and have it towed to avoid being stranded.

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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