This content was compiled automatically and has not yet been reviewed by a technician. For reference only.
For reference only. Always confirm part numbers and procedures for your specific vehicle.
Fault diagnosis
MG HS Plug-in Hybrid P1E5C / P1EAF: Internal BMS relay repair case involving charging failure
The vehicle would not charge and displayed a high-voltage fault warning, but could still be driven in this case; both codes appeared together.
MG HS Plug-in Hybrid P1E5C / P1EAF: Internal BMS relay repair case involving charging failure
Symptoms
- The vehicle would not charge and displayed a high-voltage fault warning, but could still be driven in this case; both codes appeared together. [1]
Diagnostic trouble codes
- P1E5C (manufacturer): On-board charger relay open failure (description in the original case) [1]
- P1EAF (manufacturer): On-board charger voltage mismatch (description in the original case) [1]
Possible causes
- The repairer found a sticking 12V contactor/relay inside the BMS in this vehicle, causing a voltage mismatch seen by the charger; this conclusion applies only to this case. [1]
Checks
- First confirm the fault codes and charging operating status. Then have a qualified high-voltage technician safely isolate the system and inspect the BMS and integrated contactor assembly. The source provides no pin assignments, limits or step-by-step measurement details; do not add them. [1]
What to do
- In the original case, the relevant internal BMS components were repaired and reassembled, followed by charging verification, code clearing and a road test. This does not require replacement of the OBC, complete BMS assembly or entire battery pack. [1]
Applicability and limits
- Only applies to the MG HS Plug-in Hybrid in the publicly available KMC Electric repair case; the model year, battery configuration and ECU recording the fault codes were not disclosed. Do not extend to combustion-engine HS models or all HS hybrid versions. No vehicle model has been linked. Scope: unknown [1]
- Plug-in Hybrid; must not be treated as a combustion-engine HS
- A single-vehicle case with two concurrent codes
- No model year or battery version is specified
Related part categories
- Internal BMS contactor/relay (classification pending) / Internal BMS contactor/relay / High-voltage charging control [1]
Sources
[Source 1] KMC Electric: MG HS Hybrid Not Charging Repair — HV System Fault & On-Board Charger Fault Diagnosis; Common MG HS Hybrid Fault Codes; What Caused the Fault?; Our Repair Process (accessed 2026-11-01)
https://www.kmcelectric.co.uk/page/mg-hs-hybrid-not-charging-repair
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