The crankshaft position sensor can be considered the beating heart of the ignition system. And your 3.4L V6 Buick (Oldsmobile) comes equipped with two of them (a 7X CKP sensor and a 24X CKP sensor).
In this tutorial I'll answer some of the most commonly asked questions about these two CKP sensors.
Contents of this tutorial:
- How Many CKP Sensors Does My Car Have?
- What Does The CKP Sensor 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 3.4L V6 Buick, Oldsmobile Tutorials.
APPLIES TO: This tutorial applies to the following vehicles:
- 3.4L V6 Buick Rendezvous: 2002, 2003, 2004, 2005.
- 3.4L V6 Oldsmobile Alero: 1999, 2000, 2001, 2002, 2003, 2004.
- 3.4L V6 Oldsmobile Silhouette: 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004.
How Many CKP Sensors Does My Car Have?
Yes, your 3.4L V6 equipped Buick (Oldsmobile) does come equipped with two CKP sensors.
Here are some important details about them:
- 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.
What Does The CKP Sensor Do?
Although both sensors are tasked with the job of keeping an eye on the position of the crankshaft, they both have a very specific role to play in your vehicle's ignition system. Here are the specifics:
The 7X crankshaft position sensor:
- Connects directly to the ignition control module (ICM).
- Used by the ignition control module to activate the ignition coil packs (to fire spark to the spark plugs).
- Used by the fuel injection computer to activate the fuel injectors.
The 24X CKP sensor:
- Connects directly to the fuel injection computer.
- The 24x CKP sensor signal is used by the fuel injection computer to accurately control the spark the ignition system produces at very low RPMs (usually under 2,000 RPMs).
What Happens When A CKP Sensor Goes Bad?
When either of the crankshaft position sensors fail, your 3.4L Buick (Oldsmobile)'s fuel injection computer will not receive any crankshaft position information.
In particular, the lack of the 7X CKP signal will definitely cause some serious problems.
In the next section, I'll explain some of the symptoms you'll see with a bad CKP sensor.
What Problems Can A CKP Sensor Cause?
In a nutshell, a bad 7X crankshaft position sensor will cause the engine to not start.
To be a bit more specific, with a bad 7X CKP sensor you'll see that:
- None of the ignition coil packs will fire spark.
- The fuel injectors will not be activated.
When the 24X CKP fails, the engine will usually start and run, but run badly. In some cases the engine will not start or if it does, will stall.
The fuel injection computer is designed to register a CKP diagnostic trouble code when the sensor fails, but it rarely does. In the rare instances it does set a CKP sensor diagnostic trouble code, you'll see one of the following:
- P0336: 24X CKP Sensor Circuit Problem
- P1374: 7X CKP Sensor Circuit Problem
How Can You Tell If A CKP Sensor Is Bad?
The only way to find out if the 7X CKP sensor or the 24X CKP sensor is bad (or not) is to test it. Testing them is not hard!
In the next section, I'll explain what's involved in testing them.
How Can I Find Out If A CKP Sensor Is Bad?
As mentioned earlier, testing either crankshaft position sensor is the only way to find out if it has failed or not.
Testing the CKP sensor follows the following procedure:
- 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 7X CKP sensor is OK).
- 7X CKP sensor:
- Make sure that the 7X 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 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 the 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 3.4L V6 Buick, Oldsmobile Tutorials
You can find a complete list of 3.4L V6 Buick (Oldsmobile) tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- What Do The Spark Plugs Do? (3.4L V6 Buick, Oldsmobile).
- How To Test The MAF Sensor (3.4L V6 Buick, Oldsmobile).
- What Does The CKP Sensor Do? (3.4L V6 Buick, Oldsmobile).
- How To Test The Throttle Position Sensor (3.4L V6 Buick, Oldsmobile).
If this info saved the day, buy me a beer!