Error Code P06BD is defined as Cylinder 5 Glow Plug Circuit Range/Performance. This is a generic trouble code, meaning it applies to all cars equipped with the OBD-II system, especially those made since 1996 up to present. This includes 1998 Land Rover Discovery Series I models from but not limited to Audi, Chevrolet, Citroen, Dodge, Ford, GMC, Peugeot, Ram, Toyota, etc. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model, and powertrain configuration.
Diesel engines come equipped with glow plugs in each cylinder to increase the cylinder temperature to maximize compression. This is because it needs high compression rather than a spark plug to initiate the movement of the piston.
Glow plugs (often confused with spark plugs) are placed in each cylinder, threaded to the cylinder head. A battery voltage is applied to the glow plug element (through plug timer, also known as glow plug controller, or glow plug module) and the PCM. If a correct voltage is applied, the glow plug will glow red hot to increase the cylinder temperature. Once the cylinder temperature reaches the desired temperature level, the control unit will then restrict voltage, allowing the glow plug to return to its normal state.
When Error Code P06BD appears, this means the PCM (powertrain control module, also known as ECM or engine control module in other 1998 Land Rover Discovery Series I makes) has detected a discrepancy in the glow plug control circuit cylinder number 5. When diagnosing this code, it’s important to consult with the reliable 1998 Land Rover Discovery Series I information to determine the exact location of the #5 cylinder for the year, make, model, and power configuration.
If the PCM detects a voltage level that is outside the expected range, then it will register the Error Code P06BD and trigger the Check engine light.
Engine misfire codes may be present along with the P06BD.
Checking this code requires a DVOM (digital volt ohmmeter), dependable 1998 Land Rover Discovery Series I information for TSB (technical service bulletin) that has the code stored, 1998 Land Rover Discovery Series I (year, make, model, engine), and exhibited symptoms. Finding the right TSB can lead you to more easy and successful diagnostic and repair procedure.
You may also need the diagnostic flow chart for the code, including the connector face views, wiring diagram, connector pin out charts, component locations, and component test procedure/specifications from your 1998 Land Rover Discovery Series I information source. You will need all this information for proper diagnosis of your 1998 Land Rover Discovery Series I .
Start your diagnosis by inspecting all glow plugs and glow plug control connectors and wirings. Then, connect the diagnostic scanner to your 1998 Land Rover Discovery Series I diagnostic port. Retrieve all stored codes and freeze frame data, then record it for later.
Next, take your 1998 Land Rover Discovery Series I for a test drive to see if the code comes back. Drive until one of two things happens: either the PCM enters readiness mode, or the code resets. If the code does the latter, then continue with the diagnosis. If it does NOT, then you’re having an intermittent condition, which means you may have to wait for the problem to worsen before you can accurately diagnose it.
One good way to test the glow plug is to remove them and apply battery voltage. If the glow plug glows bright red, then it’s in good condition. If the glow plug fails to glow, that means it’s not heating up. You may want to take time and test it using DVOM. Most likely, you will find out it doesn’t meet the specifications set by the manufacturer. Be careful in doing this test, as the glow plug can be extremely hot.
If the glow plug seems to be working correctly, then use a scanner to activate the glow plug timer, and test for battery voltage (make sure to test ground as well) at the glow plug connector (use DVOM. If there’s no voltage present, then test the power supply for the glow plug timer, or glow plug controller. Test all related fuses, and relays as recommended by the manufacturer. It’s best to test the system fuses and fusible links with the circuit loaded. The fuse for a circuit that is not loaded may appear functional, when it’s not, leading you to a wrong path of diagnosis.
If the fuses and relays seem to be in good shape, then test the output voltage at glow plug timer or PCM (wherever it comes from) using a DVOM. If you’re able to detect a voltage at the glow plug timer or PCM, then you can suspect an open or shorted circuit. You can search for the cause of the discrepancy, or simply replace the circuit.
Common repairs for this code include:
In other cases, Error Code P06BD can’t be caused by a defective glow plug because it’s a control circuit code. But don’t be deceived, as a bad glow plug may cause variations in the control circuit that can result in such a code.
Diagnosing the wrong cylinder is pretty common, and can be a huge headache. Thus, save yourself from trouble and make sure you’re addressing the right cylinder before starting your diagnosis.