U0273: Lost Communication With Lighting Driver Control Module A
What to do
Get somebody to stand outside the car while you work the lights, indicators and brake pedal. That takes two minutes and tells you whether this is urgent. If headlamps are out, the car is not roadworthy after dark; if brake lights or indicators are out, it is not roadworthy at all.
This module is the power electronics that drives LED lighting. LEDs need carefully regulated current rather than simply being switched on, so every LED lamp has a driver behind it — and when the driver fails the lamp goes out even though the LEDs themselves are perfectly good.
That matters commercially, so ask the question directly: is it the driver or the lamp? On many cars the LEDs cannot be replaced separately, so a lamp assembly is a large bill — and if the actual fault is the driver, that bill may not be necessary. It is a fair question, and worth asking before anything is ordered.
Mention any misting or water inside the lamp units, since these drivers run hot and sit where moisture reaches them.
What this code means
The first lighting driver control module has stopped being heard from. See U0200 for the block's framing and U0241 for the headlamp control module, which is a different thing.
The distinction between a lighting control module and a lighting driver module is worth getting right, because it decides what has actually failed. A control module decides what should be lit. A driver module is the power electronics that makes it happen — the constant-current supplies that feed LED strings, which cannot simply be switched across the battery the way a filament bulb could.
An LED needs current regulated, not voltage applied. Its brightness and its life depend on that regulation, and getting it wrong destroys the diodes quickly. So every LED lamp on the vehicle sits behind a driver, and losing the driver takes the lamp out regardless of how healthy the LEDs themselves are.
That is the expensive part, and it is why this page exists. On many vehicles the LEDs are not serviceable separately from the lamp assembly, so a fault that would once have been a bulb is now potentially a complete unit. But a failed driver is not a failed lamp — and establishing which of the two has gone is worth a great deal of money.
Ask for that distinction explicitly before a lamp assembly is ordered.
The symptom depends on which lighting the driver feeds, and the roadworthiness consequences at U0241 and U0252 apply in full: headlamps out after dark, or brake lights and indicators that cannot be seen from the driving seat. So the first practical step is the same one — establish what is actually lit, with somebody standing outside the vehicle.
Physically, drivers run hot by nature — they are dissipating the difference between supply voltage and what the LEDs need — and they are mounted in or beside lamp units where ambient temperature is already high. Heat, and the moisture that gets into an ageing lamp housing, account for most of these.
Likely causes
Start here
- Water ingress into module · moderate
- Corroded or loose connector · easy
- Heat damage to sensor or wiring · moderate
- Failed power or earth supply to the module · moderate
Less common
- Damaged wiring harness · moderate
- Blown fuse or failed supply · easy
Symptoms
Components involved
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.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
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.
Sign in or create an account to add what you found about U0273.