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Symptom

Problems started after battery work or a jump start

Faults, warning lights or odd behaviour dating from the moment the battery was changed, disconnected or jumped. Two quite different things hide behind one event. Disconnecting the battery makes modules forget what they had learned — throttle positions, window travel, steering angle, radio security — so a car that needs re-teaching is not broken and is fixed by procedure rather than by parts. A jump start is the other story: connected the wrong way round, or with the leads pulled off while the engine runs, it can put a voltage spike through everything at once. Say which of the two it was, because one costs minutes and the other can cost a module.

Also described as: after changing the battery, since the battery was disconnected, after a jump start, started when i fitted a new battery, faults after battery change, بعد از تعویض باتری, بعد از باتری به باتری کردن, despues de cambiar bateria, le di corriente, despues de hacer puente, tras pasar corriente, بدأت بعد تغيير البطارية, بعد ما أعطيتها كهرباء, بعد شبك البطارية, بعد ما غيرت البطارية

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Some causes mean you should stop driving

9 of the 102 codes that produce this symptom indicate a fault where continuing to drive risks damage or is unsafe. If the symptom is sudden or severe, treat it as one of those until a scan says otherwise.

What this usually means

Two quite different things hide behind one event, and saying which it was decides whether this costs minutes or a module.

Disconnecting the battery makes modules forget what they had learned — throttle positions, window travel, steering angle, radio security, transmission adaptation, and on many cars the battery's own registration. A car that needs re-teaching is not broken and is fixed by procedure rather than by parts. That is the large, cheap, common half, and it accounts for most of these complaints: windows that no longer one-touch, a steering or stability lamp, a rough idle for a few days, a transmission shifting oddly until it relearns.

Battery registration deserves naming separately, because its symptom is delayed rather than immediate. On a car with energy management, a replacement battery that was never registered leaves the charging strategy working to the old battery's ageing profile — so the new battery is undercharged into sulphation and fails early, and the complaint arrives months later as "the new battery has gone flat too".

A jump start is the other story. Connected the wrong way round, or with the leads pulled off while the engine runs, it can put a voltage spike through everything at once — and that damages modules rather than confusing them. Say which of the two it was.

After a spike, scan every module rather than the powertrain alone, and expect the damage to be where nobody would look: a module on the same supply as whatever was connected, not necessarily near the battery. A fuse that has blown is good news — it did its job.

And a car that simply sat with a flat battery is a third case. Everything that follows may be the flat battery's own consequences rather than the jump start's.

Working through it

  • Windows, sunroof or seats no longer work automatically

    Likely cause
    Learned travel limits lost on disconnection — not broken
    How to confirm it
    This is normal after any disconnection. Check the handbook for the vehicle's relearn sequence, which is usually holding the switch at the end of travel.
    What fixes it
    Run the relearn. No parts, no scan tool, a few seconds per item.
  • Steering, stability or throttle lamp lit since the battery came off

    Likely cause
    Calibrations lost — steering angle reference and throttle adaptation are the usual two
    How to confirm it
    Read live steering angle with the wheels straight and live closed-throttle position against specification.
    What fixes it
    Run the manufacturer's calibrations. A part fitted for this is a part wasted.
  • New battery, and months later it has gone flat too

    Likely cause
    The battery was never registered, so the charging strategy still works to the old battery's profile and undercharges it
    How to confirm it
    Read the battery data stored in the energy-management module and compare it with the battery actually fitted.
    What fixes it
    Register the battery — type, capacity and serial. Check AGM was not replaced with flooded while you are there.
  • Jump leads connected the wrong way round, or removed with the engine running

    Likely cause
    A voltage spike through the whole vehicle — this damages modules rather than confusing them
    How to confirm it
    Scan every module, not just the powertrain. Check every fuse, including the high-current ones in the engine bay.
    What fixes it
    Replace blown fuses and repair the modules the scan names. A fuse that has blown is good news.
  • Rough idle or odd shifting for a few days, improving with use

    Likely cause
    Adaptations relearning themselves as the car is driven
    How to confirm it
    Note whether it is improving. Improvement over a few hundred miles is relearning rather than a fault.
    What fixes it
    No repair. Drive it. If it is not improving after a week, treat it as a genuine fault.
  • Faults date from the battery having gone flat rather than from the jump

    Likely cause
    The flat battery's own consequences — modules recording faults during the brown-out
    How to confirm it
    Clear the codes and re-scan after a drive. Codes set during a brown-out are consequences rather than faults.
    What fixes it
    Only diagnose what returns. Test the battery itself, since one that went flat may not have recovered.

Codes that produce this symptom (102)

Listed with the codes that most typically present this way first — the likeliest place to start.

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

Others with this symptom

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What makes one worth reading:

  • The car — make, model, year and engine. The same fault behaves differently on each.
  • What you measured, not only what you replaced.
  • What actually fixed it — or that nothing did, which is worth knowing too.

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