An engine code of P0336 indicates a crankshaft sensor performance problem. It requires a code scanner to extract the codes from the computer. When an erratic signal or loss of signal from a sensor occurs, the computer records the fault in memory in the form of a 5-digit code. It will start with a letter followed by four numbers. The code scanner displays all fault codes stored, which can be cross-referenced with the scanner's accompanying code sheet. This will give a description of the code. A oscilloscope type scanner is necessary to test for irregularities or poor performance on most sensors. It is difficult to check sensors for anything but a major failure with a voltmeter due to their fast duty cycle.
Plug the code scanner into the OBD port under the dash to the left of the steering column. Turn the ignition key to the on position but do not start the vehicle. Record the code or codes displayed by the code scanner. Cross-reference the code with the code sheet to find out exactly what was wrong with the signal. There may be several different problems with one sensor.
Connect the engine scanner according to the instructions it gives of the specific problem. In this particular case, you are checking the crankshaft sensor since the code denotes a performance problem.
Check the crank sensors for a clear signal with no dropouts or glitches. The Vantage shows two separate crank sensors -- one a hall-effect (fixed electromagnet that senses metal slots in the crank pulley) that produces a DC signal located behind the crankshaft pulley, the other is a round cylindrical signal generator producing AC voltage located in the side of the block under the exhaust manifold and just above the oil pan on the firewall side.
Read the instructions on the scanner for the sensor being tested. The first dialogue is a description of operation. The next item is its location, followed by the best test location. In this case, it states that it is easier to test at the ignition control module connector. The next item is the connector, location, color and mission of all wires and voltages on the wire. The last item is the different tests. For this, the oscilloscope is used. A picture is displayed of a good signal for comparison purposes. Start the vehicle and watch the screen for anything irregular. Check all spikes for uniformity: Their peaks and durations should be the same as the illustrated picture. A dialogue is also provided with all the parameters necessary for a clean signal. Any differentiation or irregularities is reason to replace the sensor. If a computer receives an irregular signal, it will lock itself on to the last intelligible signal and will not change until the sensor is replaced.
