Crankshaft position sensor A circuit

Tiny
KALAKA
  • MEMBER
  • 1997 NISSAN TRUCK
Engine Mechanical problem 4 cyl Four Wheel Drive Manual 150, 00 miles

i just failed a smok check because of the crankshaft position sensor A circuit. Can you please tell me what that means and how to fix it. Thank you
Saturday, September 27th, 2008 AT 9:21 AM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
It sounds like one of two things has happened, either the sensor is unplugged or it is shorted. Here is a guide to help you see what you are in for when checking and changing the sensor which is located at the rear of the engine (diagram below).

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

From the book:

CRANKSHAFT POSITION (CKP) SENSOR

1. Check Ground Circuit - Turn ignition off. Disconnect CKP sensor harness connector . Using an ohmmeter, check continuity between CKP sensor harness connector terminal No. 2 (Green wire) and ground. If no continuity exists, repair open in Green wire. If continuity exists, go to next step.

2. Check Input Signal Circuit - Leave ignition off. Disconnect ECM harness connector. Using an ohmmeter, check continuity between ECM harness connect or terminal No. 53 and CKP sensor harness connector terminal No. 1 (Red wire). If no continuity exists, repair open in Red wire. If continuity exists, go to next step.

3. Check Component - Verify flywheel gear teeth are not damaged. If chipping or damage is observed, replace flywheel or drive plate. Disconnect and remove CKP sensor. Loosen sensor fixing bolt. With ambient temperature about 68 °F (20 °C), measure resistance between CKP sensor terminals. Resistance should be 167-204 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace CKP sensor.

4.Disconnect ECM wiring harness connector. Check connector pins for damage or corrosion. Check all circuit connectors for clean, tight fit and service if necessary. If fault is still present, replace CKP sensor.


https://www.2carpros.com/forum/automotive_pictures/62217_nisc_1.jpg



https://www.2carpros.com/forum/automotive_pictures/62217_nisb_2.jpg



Larger diagrams (BELOW)

Please let us know what happens so it will help others.

Cheers, Ken
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Wednesday, October 18th, 2017 AT 3:11 PM

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