P068F - OBD Trouble Code

<<See All OBD Codes

P068F trouble code can be defined as Cylinder 8 Glow Plug Control Circuit High.

If the error code P068F is appearing, then it would mean that the powertrain control module (PCM) has detected a discrepancy in the glow plug control circuit for cylinder #8. You can always consult a source of reliable vehicle information to determine the location of the #8 cylinder for your year / make / model / powertrain configuration.

High compression is used by diesel engines instead of spark to initiate piston movement. Since there is no spark involved, cylinder temperature must be increased to maximize compression. Glow plugs are used in each cylinder to accomplish this increase.

A glow plug for each individual cylinder is threaded into the cylinder head. Battery voltage is applied to the glow plug element via a glow plug timer (sometimes called a glow plug controller or glow plug module) and/or the PCM. If the voltage is properly supplied to the glow plug, it will literally glow red hot and aid in increasing cylinder temperature. If the cylinder temperature would reach the desired level, voltage is restricted by the control unit and the glow plug returns to it's normal state.

If the PCM detects a level of voltage, for the cylinder #8 glow plug control circuit that is outside the expected range, a code P068F will start triggering up and there would be an illumination of the check engine light on the dashboard.

What causes this problem with the Cylinder 8 Glow Plug Control Circuit High?

• There can be opened or shorted glow plug control circuit
• Some faults in the glow plug
• The glow plug connector might be loose or faulty
• Quirks in the glow plug timer

1. Engine Wiring Harness - Did your mechanic just found out that there is some fault in the Engine Wiring Harness? Buy top notch Engine Wiring Harness from us at economical prices.
2. Powertrain Control Module - A broken Powertrain Control Module can cause a lot of issues. It would be nice if you get it replaced on time.
3. Glow Plug Connector - Everything is fine with the engine control module and still OBD code P068F flashing? Then there is definitely some fault with the Glow Plug Connector. Get it checked and replace if needed.
4. Engine Control Module - Engine Control Module is an important car part which should never be neglected. May be there is some fault in it due to which P068F code may start flashing.
5. Body Control Module Component - A faulty Body Control Module Component can be troublesome. You can always rely on us as we have best auto parts for our customers.
6. Electronic Control Unit - If everything is alright with PCM, then there is surely some defect in Electronic Control Unit. Get it replaced before the situation gets worse

Our main motive is to achieve customer satisfaction as for us our customers are everything and that’s why we will help you to diagnose P068F code by mentioning some major symptoms below:

Common Symptoms

• Immoderate black smoke from exhaust
• Engine drivability issues
• Slow down engine starts up
• Diminishing fuel efficiency
• Some engine misfire codes may be stored

If you wish to correct this fault code, then you have to follow certain steps. Correcting a problem needs your careful attention. Here are some ways with the help of which you will be able to correct the OBD Code P068F:

• Restore the opened or shorted glow plug control circuit
• The glow plug connector might be loose or faulty. So, you must get it repaired or replaced
• Carefully inspect the glow plug timer
• If there are a few defects in the glow plug then it should be replaced

However, if you face any issue then we have stocked a wide range of best priced cylinder head gasket, electrical components, glow plug connector, engine rebuilders, relay switch, starter relay, solenoid, engine cylinder, diesel glow plugs, gas engine and more to help you out in fixing your car.

Here are some steps which you should follow in order to diagnose this fault code:

You should use a diagnostic scanner, a reliable source of vehicle information, and a digital volt/ohmmeter (DVOM) in order to arrive at an accurate diagnosis of a code P068F. Use the vehicle information source to search for applicable technical service bulletins (TSB). If you locate a TSB that matches the vehicle make and model, symptoms exhibited, and the code stored, it will help you to arrive at a diagnosis

You may also need to obtain diagnostic flow charts, wiring diagrams, connector face views, connector pinout charts, component locations, and component testing procedures/specifications from the vehicle information source. All this information will be needed to correctly diagnose the stored code P068F

Now once you have performed a careful visual inspection of all glow plug and glow plug control wiring and connectors, connect the diagnostic scanner to the vehicle diagnostic port. Then retrieve all stored codes and freeze frame data and record it for later. After that test drive the vehicle to see if the code P068F is reset. Drive until one of two things happens: Either the PCM enters readiness mode or the code is reset. If the code is reset, continue with the diagnosis. If it is not, you are dealing with an intermittent condition which may have to worsen before an accurate diagnosis may be achieved.

Here is a tip that the service manual will not give you. The best way to test glow plugs is to remove them and apply battery voltage. If the glow plug glows bright red, it is good. If the glow fails to heat up, and you want to take time to test it with your DVOM, you will likely discover that it does not meet manufacturer's specifications for resistance. Be careful not to burn yourself or start a fire when performing this test.

If the glow plugs appear to be working properly, use the scanner to activate the glow plug timer and test for battery voltage and a ground at the glow plug connector. If no voltage is present, test the power supply for the glow plug timer or glow plug controller. Test all related fuses and relays as recommended by the manufacturer. As a rule, it best to test system fuses and fusible links with the circuit loaded. The fuse for a circuit which is not loaded may appear to be functional (when it is not) and lead you down the wrong diagnostic path.

If all fuses and relays appear functional, use the DVOM to test output voltage at the glow plug timer or PCM (wherever it originates). If voltage is detected at the glow plug timer or PCM, suspect that you have an open or shorted circuit. You may seek out the cause of the discrepancy or simply replace the circuit.

Common Mistakes When Diagnosing The P068F Code

• Glow plug might be defective
• Flaws in the glow plug wiring harness
• Failure in the glow plug control module
• People think that a P068F cannot be caused by a defective glow plug because this is a control circuit code. Don't be deceived; a bad glow plug may cause a variation in the control circuit that result in just such a code
• Huge mistake of attempting to diagnose the wrong cylinder is made by a lot of people. Save yourself a big headache and make sure that you are addressing the correct cylinder before beginning your diagnosis