Cars used to let you know that they weren't quite right by coming to a shuddering halt at the side of the road, usually accompanied by an expensive-sounding noise and a cloud of smoke. Not any more though. These days, a car can tell you pretty much what's ailing it through a warning light and a fault-code reader. Click here to see our test of the best fault-code readers you can buy.
Here, we explain what some of the most common fault codes mean.
C1234
This is a code that indicates an issue with the vehicle's ABS (anti-lock braking) system. This could be anything from a faulty wheel speed sensor to a damaged hydraulic unit or even a broken ABS control module.
What are the symptoms of the C1234 code?
The warning light will be illuminated on the dashboard, and you may notice a decrease in braking power, so you'll have to press the brake pedal harder to achieve your normal stopping distance. You might also hear an intermittent grinding noise from the brakes, or experience vibration, or a pulsing sensation, when braking.
What causes the C1234 code?
This code could be caused by any of the following: faulty wheel speed sensors, damaged hydraulic unit, broken ABS control module, corroded or loose wiring, leaky brake fluid lines or a poor connection between the wheel speed sensor and the ABS control unit.
Can you drive with a C1234 code?
Yes, you can. Most of the time, this code indicates a minor problem that will just reduce your car's braking power slightly. However, if left unchecked, the issue can become worse and could eventually leave you stranded somewhere.
And bear in mind that if you delay fixing the fault and have an accident while it is present, you could be held liable and face legal proceedings.
How to diagnose a C1234 fault code
To diagnose this fault code, you will need to read the code with an OBD-II scanner and then use a series of tests to determine which component is causing the problem. You should also check for any broken or corroded wiring, as well as make sure that all connections are secure and the brake fluid level is correct.
How to fix the C1234 code
Fault code C1234 is often caused by a faulty ABS sensor. In most cases, this sensor can be found on the wheel hub or on the axle of your car. Diagnosing and replacing a faulty ABS sensor is relatively easy and can usually be done without the need for any specialist tools.
In addition, a throough check of the brake system's wiring should be carried out. And of course, if you have any kind of braking issue, you should first make sure that there's enough brake fluid in the system, so check the reservoir.
If you can't find the fault with these check, it could be the ABS control unit itself that's at fault, and this will need to be replaced.
So, check out your car's Haynes manual for all the information you'll need.
