What people are finding on real cars — write-ups, questions and tips, each attached to the code or part it is about. Reading needs no account.
78 posts match.
Almost every disappointment people have with a scan tool comes from the same misunderstanding: OBD-II is an emissions regulation that turned out to be useful for diagnosis, not a d...
A hydraulic power steering system spends its whole life telling you how it is doing, and the noise it makes is the most specific thing it says. A whine that rises as you turn and f...
Fuel consumption is the most useful number a car gives you, and almost nobody writes it down. That is the whole argument of this article, and it is worth stating before anything el...
There are two questions you can ask about a bottle of engine oil. The first is whether it is synthetic or mineral. The second is whether it is the right oil for your engine. The pi...
Most guides to inspecting a used car are written in the order that sets the price. This one is written in the order that ends the viewing. That distinction is the whole argument, a...
An engine mount has two jobs that pull in opposite directions, and everything about it is a compromise between them. It must be stiff enough to hold a heavy engine still — against...
One difference produces all the others, and the source states it twice — once wrongly and once correctly, three paragraphs apart. The wrong version opens the article: the fuel and...
Very little is written in English about running a car on compressed natural gas, and a great deal of the world does it. This is a merge of five pieces from an archive written for a...
A carburettor is a remarkable piece of engineering that solves a hard problem with no electricity, no sensors and no moving decisions: it measures airflow and adds the right amount...
Car lighting is the one system where you cannot see your own failure. Every other fault announces itself to the driver; a dead brake light announces itself only to the person behin...
A relay is a switch operated by a magnet instead of a finger, and its whole purpose is to keep heavy current away from places heavy current should not go. The original puts that be...
Everything a car does — accelerating, braking, steering, staying on the road — happens through four patches of rubber roughly the size of a hand. Nothing else on the car is asked t...
The corpus opens its page on the turbocharger by saying they are blamed for far more faults than they cause, and that is the right place to start — but this article is about the ti...
The whole braking system rests on one property of liquids: they do not compress. Push on a column of fluid at one end and the far end moves immediately, by the same amount, with no...
Three angles decide how a car tracks, how it steers and how long its tyres last, and the useful thing about them is that the tyre keeps a record. A tyre that is wearing wrong is te...
A brake does one thing: it turns the car's motion into heat and throws the heat away. The original opens with the arithmetic and it is worth keeping because the number is genuinely...
A spring and a damper are fitted together, replaced together and usually talked about as one thing. They do opposite jobs, and the difference between them is the single most useful...
The corpus describes transmission slip as engine speed rising without a matching increase in road speed, and says to treat it as a fault. On a CVT that is the normal, designed beha...
"Does it have four-wheel drive?" is close to the wrong question. Two vehicles can both answer yes and behave completely differently in the situation you bought it for. Th...
Both sources for this article describe the differential as intelligent. One calls it a smart distribution box that works out which wheel can take more speed. The other says it divi...
Move the lever and a gear engages, silently, in about a fifth of a second. That is a much harder thing than it looks, and understanding why explains every fault a manual gearbox ha...
The AL4 — sold as the DP0 by Renault — is in a very large number of cars: the automatic 206 and Pars, the 307 and 407, the Xsara and Xantia, the Mégane and Scénic. It is a competen...
A noise carries four pieces of information, and people reach for them in almost exactly the wrong order. What it sounds like — tick, knock, rattle, whine, squeal, puff. When it hap...
A clutch exists because an engine cannot start from rest and a gearbox cannot change ratio under load. Everything else about it follows from those two sentences, and the original s...
An engine that is burning oil and an engine with a failed head gasket are the same kind of fault: something is crossing a boundary that is supposed to be sealed. They are told apar...
Real code numbers nobody has written up yet · Have you met this code? What did your scan tool call it, what car was it on, and what turned out to be wrong? Anything you add here becomes the page for the next person who searches it.