The 3X-18X crankshaft position (crak) sensor, on the GM 3.8L V6 engine, can easily be tested (to find out if it's bad or not) with a multimeter. With this article, I'll walk you thru' the entire crank sensor testing process in a step-by-step manner.
In case you're wondering if you can test the crank sensor with a simple resistance test (ohms)... let me tell you that it's not possible. That's right... the 3X, 18X crank (CKP) sensor can not be tested with a simple Ohm (resistance) test. Why? Well, because the 3X, 18X crank sensor is a Hall-Effect Type sensor and this type of sensor does not allow for a resistance test.
A Hall Effect sensor has to be tested in action. The crank sensor test I'm gonna' show you here is one of the most effective and sure ways to troubleshoot the sensor using just a multimeter in Volts DC mode.
If you need to know if this 3X 18X crank sensor test applies to your specific 3.8L GM vehicle, take a look at the ‘Applies To:’ box on the right and scroll with the ‘Next > >’ button to see all of the applications. Also, the info in this article is geared towards diagnosing and troubleshooting a ‘cranks but does not start condition - no start no spark condition’.
Here are the contents of the 3.8L crank sensor test at a quick glance:
The most obvious symptom of a BAD crank sensor is your vehicle's engine not starting. In automotive tech terms, this condition is better known as a ‘cranks but does not start condition’.
Below is a simple list of more specific symptoms that accompany a BAD crank sensor:
Taking all of the above into account, the most important thing to remember is that if you get spark from any spark plug wire... the crank sensor is working and the test in this article won't help you.
The 3X 18X crankshaft position sensor is two crank sensors in one assembly and is a Hall-Effect type sensor that needs an external power and ground source to create its crank (CKP) signal. As such, it produces an On/Off DC voltage signal that can be measured with a multimeter, an Oscilloscope, and even an LED Light.
Here, in a nutshell, is 3.8L/how the crank sensor works:
The most important thing to know about the 3X 18X crank sensor is that if it goes BAD, your 3.8L V6 equipped GM car or mini-van will crank but not start due to a lack of spark and fuel injection.
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