The customer came in and complain that the engine cut out sometimes and then she must restart the car, fortunately, the engine start immediately after it cut out. The first thing I have done is to plug in the scanner to see what faults are there. The following faults were present in the ECU:
P0325 KNOCK SEN/CIRC-B1
P0335 CKP SEN/CIRCUIT
The code P0325 KNOCK SENSOR cannot cause the engine to cut out. I am concentrating on the crank sensor, this sensor could cause the engine to cut out while you are driving. The customer said that it does not happen every day maybe say three times a week. This makes it difficult because I can’t keep the car for a long time or a week or more to test the crank sensor. What I have done is to set up the picoscope and back probe the signal wire of the sensor, this sensor is a 3-wire sensor. Channel 2 is connected to coil number 1.
I have run the engine for a while (10Min) and I could see nothing wrong, the signal looks great, see the following image:
I let the engine idle for a longer time and after say 30 min I start to rev the engine since then I saw some irregularities with the waveform, see the image below.
I have marked the waveform where it started to show irregularities, it looks like the sensor starts to have internal short or just become weak. I actually was hoping the sensor would change to just a straight line, but this was enough for me to see that there is something wrong with the sensor. I bought a sensor from the agents, and after fitting it I gave the car to the customer and she has had no complaints since the repairs.