P0A29 fault code: Battery Power Off Circuit High
Pull over safely as soon as you can and switch the engine off. Do not keep driving. Arrange recovery or a trailer to a qualified garage — continuing risks further damage or an unsafe vehicle on the road. If you see damaged orange high-voltage cables, stay clear and arrange recovery — do not probe the high-voltage system.
Can I DIY?
Do not DIY this repair. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage.
This fault is in the professional-only category. We do not publish strip-down or fitting steps on this page. Use a qualified garage.
Orange high-voltage cables can kill. Not a home DIY job. Workshops need competent persons (EaWR); industry benchmark is IMI EV Level 2–4. We publish no HV strip-down steps.
What does P0A29 mean?
P0A29 is a generic (SAE standard) powertrain code reported by your car’s engine control unit. It sits in the P0Axx block, which covers hybrid propulsion. The stored description is “Battery Power Off Circuit High”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.
Will P0A29 fail an MOT?
An illuminated engine management light is a Major defect at MOT since 2018 — an automatic fail until the fault is repaired and the light stays off. Clearing the code without fixing the cause is not a repair.
Before booking your test, check what usually fails on your car: see our MOT pass rates by make and model, built from 33.1 million DVSA tests.
What the MOT data says
No MOT certificate item corresponds to this code; MOT outcome data cannot be shown.
Related guides
Related fault codes
P0A29 — quick answers
Is it safe to drive with P0A29?
Stop driving now. Pull over safely as soon as you can and switch the engine off. Do not keep driving. Arrange recovery or a trailer to a qualified garage — continuing risks further damage or an unsafe vehicle on the road. If you see damaged orange high-voltage cables, stay clear and arrange recovery — do not probe the high-voltage system.
Can I fix P0A29 myself?
Do not DIY this repair. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage. Specialist tools or workshop equipment — typically a professional garage job.
Will P0A29 fail my MOT?
An illuminated engine management light is a Major defect at MOT since 2018 — an automatic fail until the fault is repaired and the light stays off. Clearing the code without fixing the cause is not a repair.
Fault-code identifiers are standard diagnostic facts. Their explanations and diagnostic guidance on this site are original editorial summaries, not reproduced SAE wording. MOT defect rules reflect the DVSA MOT inspection manual (2026). This page is general guidance for UK drivers, not a substitute for a professional diagnosis.