READING OBD1 FAULT CODES
Basic OBD1 kit
OBD1 systems vary between manufacturers, so you’ll need to find a faultcode reader specific to your classic. Connecting ports are diverse, so you may need an adaptor. Some cars require a separate plug-in tool to reset the service interval indicator.
Service indicator reset
Many cars have a dashboard service indicator. Some can be reset by pressing a combination of dashboard or steering column buttons. Others need a specific device that plugs into the OBD port. In the case of this BMW, the device is a modest £10.
Solving the problem
The next step is to resolve the faults. View replacing the suspect sensor or component as the last resort. Start by checking the condition of all associated wiring and connections. Spray all connector blocks with electrical contact cleaner.
Finding information
Two- or four-digit OBD1 faultcodes vary according to manufacturer. Searching online will usually locate a list of codes for any specific car. Alternatively, Haynes publishes a useful manual that features a directory of common OBD1 faultcodes.
Reading warning lights
Some OBD1 cars use the dashboard engine management light or a light on the ECU itself to transmit faultcodes as a series of flashes – a bit like Morse code. Check your workshop manual or search online to find out if your classic has this capability.
Clearing faultcodes
Once you’ve solved the problem, go back to the scanner’s menu and clear the fault. If it won’t clear, disconnect the battery briefly then try again. If this fails, deeper investigation is required. If the issue’s definitely fixed, the ECU may be at fault.
Locating your OBD Port
Most Obd1-equipped cars have a port to connect a scanner, either in the engine bay or inside the car. This BMW has a 20-pin connector under the bonnet. Some Eighties cars don’t have a port, transmitting fautcodes through a light instead.
Using a scanner
Plug a suitable scanner into the OBD port and it should spring to life. Use the on-screen menu to display a list of faultcodes stored in the ECU. The scanner display may explain the code, or you may need to look it up online or in a manual.
Resetting the ECU
In some cases, faultcodes can be cleared by disconnecting the battery for a few minutes. The date and time will need to be reset afterwards, as the service indicator requires this information. Radio codes will have to be re-entered, too.