Does a dashboard with no warning lights fail an MOT?

Yes, and this catches people out badly. The tester does not simply check that the lamps are off — they check that each one illuminates when the ignition is switched on and then goes out, which is the bulb check. A lamp that never comes on cannot be verified, and the manual treats that as a malfunction because it is exactly what removing a bulb to hide a fault looks like. With a dead cluster none of them appear, so the airbag, brake, stability control, tyre pressure and engine management warning systems all fail at once.

Is it illegal to drive with a broken speedometer?

It is a problem on two fronts. A speedometer that is fitted, working and readable is a requirement, and the MOT checks it directly, so a car with a dead speedometer will not pass. Beyond the test, you have no way of knowing your speed, which makes complying with speed limits a matter of guesswork. Combined with the loss of every warning lamp that a dead cluster brings, this is a car to repair before using rather than after.

Can an instrument cluster be repaired?

Usually, and it is often the better route. Specialist firms repair clusters routinely, dealing with the failed power supplies, cracked solder joints, dead displays and stepper motors that cause most failures. That matters more here than with other modules, because a replacement cluster has to have the car's correct recorded mileage written into it and be coded to the vehicle and often the immobiliser. Repairing the original avoids all of that and keeps the mileage record straightforwardly intact.

Why won't my car start with a dead instrument cluster?

Because on many cars the cluster is part of the immobiliser chain. The security system spreads its checks across several modules deliberately, so that stealing one part does not defeat it, and the instrument cluster often holds one of the stored codes that must match before the engine control unit will allow the engine to run. If the cluster is not communicating, that confirmation never arrives, and the car cranks normally without ever firing.

Network code · standard

U0155No communication with the instrument cluster

Standard definition: Lost Communication with Instrument Panel Cluster

Last updated 27 July 2026

Quick answer

The car has lost contact with the dashboard instrument cluster. You may have no speedometer, no fuel gauge and, crucially, no warning lamps at all — and a dashboard that shows nothing fails an MOT just as surely as one showing a fault.

How the car works this out

The instrument cluster is not a set of gauges wired to sensors. It is a module that receives almost everything it displays over the network — road speed, engine speed, fuel level, temperature and the state of every warning lamp — and it publishes messages of its own in return. U0155 is stored when other modules stop hearing from it. On many cars the cluster is also part of the immobiliser chain, which is why a communication fault here can stop the engine starting as well as stopping the display working.

What you might notice

Dashboard completely dead, or gauges reading zero with the engine running
No warning lamps illuminating at all when the ignition is switched on
Speedometer, rev counter and fuel gauge not working
Odometer showing dashes or nothing
Car refusing to start, where the cluster forms part of the immobiliser
Backlighting on but nothing displayed

What causes it

Most likely first. A code names the check that failed, not the part that failed it, so more than one of these can produce the same number.

1A blown fuse or a corroded terminal supplying the clusterCommon
2A corroded or partly unlatched connector at the back of the cluster, often disturbed during dashboard workCommon
3An internal cluster failure, commonly cracked solder joints, a failed power supply or a failed displayCommon
How to check: Ask about specialist cluster repair. These are routinely refurbished, which matters a great deal because a replacement cluster has to have the correct mileage written to it and be coded to the car.
4Low system voltage from a failing battery or alternatorPossible
5Damaged network wiring behind the dashboard, sometimes from aftermarket accessory installationPossible
6A wider network failure where the cluster is one of several silent modulesPossible
How to check: Check whether other modules are also missing before condemning the cluster.

What to do about it

1Do not drive it with a dead dashboard. Without warning lamps you have no way of knowing about low oil pressure, overheating or a charging failure until something is destroyed.
2Check the fuses and the connector at the back of the cluster first, particularly if anything has recently been fitted behind the dashboard.
3Have the battery and charging system checked.
4Ask about repair rather than replacement. Cluster refurbishment is a well-established trade, and a replacement unit must have the correct recorded mileage programmed into it and be coded to the car and often the immobiliser.
5Be careful about secondhand clusters. Mileage recording is a legal matter as well as a technical one, and a unit from another car brings its own recorded mileage with it.

Can you keep driving?

A dashboard that shows nothing is worse than one showing a fault, because you have lost every warning the car can give you. Low oil pressure, overheating, a charging failure or a brake problem would all pass unannounced until the damage is done, and you have no speedometer, which is a legal problem of its own. Have it recovered or repaired before driving.

Will it fail an MOT?

This is the code that best explains a rule people find surprising: a warning lamp that does not illuminate at all is treated exactly like one that stays on. The tester switches on the ignition and expects to see each lamp perform its bulb check and then go out. A dead cluster shows nothing, so the tester cannot verify the airbag, brake, stability control, tyre pressure or engine management warning systems at all, and every one of those is a major defect in its own right — 84,147 recorded failures for the airbag lamp, 85,196 for the brake system warning device, 35,322 for stability control, 97,515 for tyre pressure monitoring and 371,859 for the engine management lamp. Separately, the MOT requires a speedometer to be fitted and working.

Common questions

Does a dashboard with no warning lights fail an MOT?: Yes, and this catches people out badly. The tester does not simply check that the lamps are off — they check that each one illuminates when the ignition is switched on and then goes out, which is the bulb check. A lamp that never comes on cannot be verified, and the manual treats that as a malfunction because it is exactly what removing a bulb to hide a fault looks like. With a dead cluster none of them appear, so the airbag, brake, stability control, tyre pressure and engine management warning systems all fail at once.
Is it illegal to drive with a broken speedometer?: It is a problem on two fronts. A speedometer that is fitted, working and readable is a requirement, and the MOT checks it directly, so a car with a dead speedometer will not pass. Beyond the test, you have no way of knowing your speed, which makes complying with speed limits a matter of guesswork. Combined with the loss of every warning lamp that a dead cluster brings, this is a car to repair before using rather than after.
Can an instrument cluster be repaired?: Usually, and it is often the better route. Specialist firms repair clusters routinely, dealing with the failed power supplies, cracked solder joints, dead displays and stepper motors that cause most failures. That matters more here than with other modules, because a replacement cluster has to have the car's correct recorded mileage written into it and be coded to the vehicle and often the immobiliser. Repairing the original avoids all of that and keeps the mileage record straightforwardly intact.
Why won't my car start with a dead instrument cluster?: Because on many cars the cluster is part of the immobiliser chain. The security system spreads its checks across several modules deliberately, so that stealing one part does not defeat it, and the instrument cluster often holds one of the stored codes that must match before the engine control unit will allow the engine to run. If the cluster is not communicating, that confirmation never arrives, and the car cranks normally without ever firing.

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