My problem is the 2008 chevy trailblazer 4.2 has a 3-wire crank sensor and the reluctor ring on the crank looks similar to a bicycle sprocket.

While I did not look at the reluctor ring on the 2005 4.2 engine we installed (which I assume is different) it had a 2-wire sensor.

So either I need to find a 3-wire that would work off a 2-wire reluctor ring or find a way to wire the 2 wire sensor into the 3 wire system.

Any help is appreciated, thanks!

  • perhaps you can get a replacement wheel and sensor. Trying to convert a 2 wire signal into a 3 wire signal sounds really tricky.
    – Jasen
    Jan 24, 2016 at 11:22
  • Is your 2005 setup with a DBW throttle body? Does it actually look like there are two reluctor wheels which are side by side? What is the size difference (as per the hole) between the crank sensors which goes into the '05 and the '08 (or are they pretty much the same size)? Jan 24, 2016 at 17:26

1 Answer 1


A 3 wire CKP sensor would produce a 5v square wave. A 2 wire CKP sensor produces a AC sine wave. Even if you managed to wire the 2 wire sensor to the 3 wire harness the car wouldn't start.

You would have to swap the tone wheel if they're different.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .