THE ELECTRICAL FAULT LIGHT.June 20, 2015
This warning light is different in every car but normally it looks like a picture of a battery, similar to the picture on the left here. You’ll see it come on and go off when you start your engine as part of the car’s self-test, but if this light comes on and stays on, it means the electrical charging system is no longer working properly. Think of it like a cellphone battery. If the cellphone is plugged into the charger, you can use it indefinitely, but when you disconnect it from the charger, there’s a limited amount of time before your battery runs out. It’s exactly the same in your car, only bigger. Every car has an alternator – the charger – and a 12v battery used to supply power to the electrical system. If the alternator becomes faulty or the drive belt to it snaps, then it will not be able to do its job. The longer you drive, the more your car will use up the remaining juice in the battery and eventually the engine will die. This almost always requires a new or refurbished alternator.
THE SERVICE ENGINE LIGHT / MAINT REQD LIGHTJune 20, 2015
This might indicate “Service”, “Service Engine” or “Maint Reqd”. It’s an indicator that you’re getting close to a scheduled maintenance interval. On some cars it’s as simple as counting miles before it comes on, whilst on others it maps engine temperatures, oil temperatures, air temperatures and other indicators of probable stress to tell you when it might be time for new oil or a service. In most cars this can be overridden or reset by you, the owner. Your handbook will tell you if this is the case. If you take your car for a service, the garage should reset it for you.
Typically this light will come on when you start your car, and then turn off again as part of the self-check. If it stays on for 10 seconds then turns off, it normally means you’re within 500 miles of needing a service. If it flashes for 10 seconds, it normally means you’ve exceeded a recommended service interval.
THE CHECK ENGINE LIGHTJune 20, 2015
Every new car now comes with OBD-II – On Board Diagnostics 2. This is a fault-registering system connected to sensors all over the car, engine, fuel and emissions system. When the check engine light comes on, it can mean many things. There are something like 4,000 unique OBD2 codes that can be stored. Handheld OBD2 diagnostic tools can be plugged in to the OBD2 port which is normally under the dash on the driver’s side. These tools can read out the fault code and/or reset the system to contain no codes. Codes are split into two categories – historical/inactive, and active. The historical codes are lists of things that have been detected in the past but are no longer an issue, whilst the active codes are things that are a problem right now. Codes are subdivided into B-codes (body), C-codes (chassis) and the biggest list of all – P-codes (powertrain).