The crankshaft position sensor is the heartbeat of the ignition system of your 3.1L V6 Buick (Oldsmobile).
In this article I'm going to answer some of the most commonly asked questions about the 3X CKP sensor and the 24X CKP sensor.
Contents of this tutorial:
- How Many CKP Sensors Does My Car Have?
- What Do The CKP Sensors Do?
- What Happens When A CKP Sensor Goes Bad?
- What Problems Can A CKP Sensor Cause?
- How Can You Tell If A CKP Sensor Is Bad?
- How Can I Find Out If A CKP Sensor Is Bad?
- Can I Drive My Vehicle With A Bad CKP Sensor?
- More 3.1L V6 Buick, Oldsmobile Tutorials
APPLIES TO: This tutorial applies to the following vehicles:
- 3.1L V6 Buick Century: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005.
- 3.1L V6 Buick Regal: 1994, 1995, 1996.
- 3.1L V6 Buick Skylark: 1994, 1995, 1996.
- 3.1L V6 Oldsmobile Achieva: 1994, 1995, 1996, 1997, 1998.
- 3.1L V6 Oldsmobile Cutlass: 1997, 1998, 1999.
- 3.1L V6 Oldsmobile Cutlass Ciera: 1994, 1995, 1996.
- 3.1L V6 Oldsmobile Cutlass Supreme: 1993, 1994, 1995, 1996, 1997.
How Many CKP Sensors Does My Car Have?
Depending on your specific 3.1L V6 Buick or Oldsmobile, the engine will have 1 or 2 crankshaft position sensors.
For the most part, all vehicles 1995 and newer come equipped with two CKP sensors (a 3X CKP sensor and a 24X CKP sensor).
3.1L V6 equipped Buick and Oldsmobile vehicles older than 1995 come equipped with both sensors only if they have California Emissions. Vehicles equipped with Federal Emissions only come equipped with a 3X CKP sensor.
If the engine comes equipped with two CKP sensors, it'll have these two:
- 3X CKP sensor.
- Also known as the 7X CKP sensor.
- Also known as the Low Resolution CKP Sensor.
- Located on the side of the engine facing the firewall (it's the sensor in the photo above).
- 24X CKP sensor.
- Also known as the High Resolution CKP Sensor.
- Located on the timing chain cover and behind the crankshaft pulley.
If the engine comes equipped with only one CKP sensor, it'll only have a:
- 3X CKP sensor
- Also known as the Low Resolution CKP Sensor.
- Located on the side of the engine facing the firewall (it's the sensor in the photo above).
IMPORTANT: The 3X CKP sensor and the 7X CKP sensor are physically the same component.
What Do The CKP Sensors Do?
The job of the 3X crankshaft position sensor is to inform the ignition control module (ICM) and the fuel injection computer the crankshaft's position.
To be a bit more specific:
- The 3X CKP sensor's signal is used by the ignition control module so that it can activate the ignition coil packs (to begin firing spark to the spark plugs).
- The 3X CKP sensor's signal is used by the fuel injection computer to start injecting fuel.
The 24X crankshaft position sensor only connects to the fuel injection computer and sends it a position signal every 15° of crankshaft rotation. The computer uses this 24X CKP signal info to calculate ignition timing.
What Happens When A CKP Sensor Goes Bad?
When the 3X or the 24X crankshaft position sensors fail, they will stop sending crankshaft position info to the ignition control module and the fuel injection computer.
Especially when the 3X CKP sensor fails, there will definitely be a disturbance in the 'force'.
In the next section, I'll explain some of the symptoms you'll see when the CKP sensor fails.
What Problems Can A CKP Sensor Cause?
When the 3X crankshaft position sensor fails in your 3.1L V6 Buick or Oldsmobile, the engine is not going to start due to a lack of spark and fuel injection.
In some cases, the 3X CKP sensor fails intermittently. When this happens, the engine starts and runs fine most of the time, but every now and then it won't start or will stall out of the blue.
Usually when the 24X CKP fails, the engine will still start and run, but it will run rough and the check engine light will be illuminated.
On OBD II equipped vehicles (1995+), the fuel injection computer is designed to set a CKP diagnostic trouble code when it fails. But it rarely does.
If the OBD II fuel injection computer does set a CKP sensor trouble code, you'll see:
- P0336: 24X CKP Sensor Circuit Problem
- P1374: 3X CKP Sensor Circuit Problem
How Can You Tell If A CKP Sensor Is Bad?
The only way to find out that the 3x or 24X CKP sensors have failed and are causing a no-start problem is to test them.
In the next section, I'll explain what's involved in testing them.
How Can I Find Out If A CKP Sensor Is Bad?
Testing either the 3X or 24X CKP sensor is not as difficult as you might think, in this section I'll describe what the test involves.
This is the basic testing procedure (for both):
- Check for CKP sensor trouble codes stored in the fuel injection computer's memory.
- Check that all 6 spark plug wires are sparking (if spark is present, then the 3X CKP sensor is OK).
- 3X CKP sensor:
- Make sure that the 3X CKP sensor signal is producing an AC voltage signal as the engine is being cranked.
- 24X CKP sensor:
- Make sure that the 24X CKP sensor signal is producing a DC voltage signal as the engine is being turned by hand.
I've written a tutorial that will help you test the 3X CKP sensor (also known as the 7X CKP sensor), you can find it here:
- Testing The Ignition Module and Crank Sensor (GM 3.1L, 3.4L) (at: easyautodiagnostics.com).
You can find the 24X CKP sensor test here:
Can I Drive My Vehicle With A Bad CKP Sensor?
In the majority of cases, when a CKP sensor fails, the engine in your vehicle is not going to start.
In those instances that the engine does start, you should not drive your vehicle since you risk being stranded wherever the CKP sensor decides to stop working.
More 3.1L V6 Buick, Oldsmobile Tutorials
You can find a complete list of 3.1L V6 Buick (Oldsmobile) tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test Engine Compression Test (3.1L V6 Buick, Oldsmobile).
- How To Test A Blown Head Gasket (3.1L V6 Buick, Oldsmobile).
- How To Test The 24X Crankshaft Position Sensor (1995-1997 3.1L V6 Oldsmobile Cutlass Supreme).
If this info saved the day, buy me a beer!
