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How we decide whether you can keep driving

Updated: 2026-11-14

In short. Every code page and every search result ends in one of two verdicts, Safe to drive or Do not drive, together with how much time you have. When we are unsure, we choose the stricter answer. The verdict is a reference, not a diagnosis, and it never replaces a look at the truck.

The two verdicts

VerdictWhat it means
Do not driveStop as soon as it is safe to do so and do not keep going. The fault can damage the truck or make it unsafe within minutes.
Safe to driveThe code alone does not call for stopping on the spot. It does not mean “fine”: right below the verdict the page says how much time you have and what happens if you keep going.

How much time you have

A bare “yes” or “no” is not enough on the roadside, so each verdict comes with one of five time levels, from the most urgent to the least.

LevelWhat it means
MinutesStop now. This is the level for a real loss of oil pressure, overheating of the engine and faults of the brake system. The verdict is Do not drive.
To the nearest safe stopDo not plan a trip; get to a safe place. Typical for the exhaust filter (DPF) stages, a failing voltage supply and fuel delivery problems. The verdict is Safe to drive only for these systems, where we know what happens next. When a code is flagged critical and we have no detailed model of it, the verdict is Do not drive with this same time level.
Enough to reach the yardYou can finish the run to the base or a shop, but not carry on as usual. Typical for exhaust treatment (AdBlue), the CAN bus and intake or boost faults.
Drivable, but watch it yourselfThe code is electrical, an open, a short or a bad contact in a sensor circuit, and the value it measures is most likely fine. The system runs blind until the circuit is repaired, so you must check the real value yourself.
Until the next serviceA standalone fault with no immediate consequences for driving. Show the codes at the next service; if a second code from the same system appears, stop putting it off.

When in doubt, stricter

  • If a code is flagged critical and we have no model of what happens next, the verdict is Do not drive. What we do not understand, we do not risk.
  • If our own reading is calm but the manufacturer flags the code as critical, the time level is raised and the page says so openly: if in doubt, it is safer to stop and check on the spot.
  • If a make uses a number differently from the standard, we do not let the make's wording hide the standard meaning. Both are shown, and where they differ, the cautious reading is the one to act on.
  • If several codes appear at once, the verdict follows the most dangerous code in the list, not the likely root cause. The root cause is shown separately, so you know what to fix first.
  • When a code could be either a real fault or a sensor problem and we cannot tell which, the real fault is assumed. A wrong call on the cautious side costs less than a wrong call on the other.

Always stop if

  • a red warning lamp is on;
  • the brake pedal feels soft or goes down further than usual;
  • oil pressure is dropping.

In these cases stop as soon as it is safe, whatever a verdict on this site says. If something feels wrong to you, trust that and stop.

What the verdict is not

  • It is not a diagnosis. The site does not see your truck, your load, your route, the weather or any fault your scanner did not read.
  • It is not a promise or a guarantee that the truck will reach its destination, or that a repair will fix the problem.
  • It is not a roadworthiness or legal opinion.

The final decision is always with the driver and with a person who has the equipment to examine the truck. If you think a verdict on a page is wrong, see Corrections on the About page.

Have a code from your scanner? Look it up — or paste the whole list and we will show which fault is the root cause.