The crankshaft position sensor is a critical component of the ignition system of your 3.4L V6 Chevrolet (Pontiac). And as you're probably already aware, the 3.4L V6 GM engine comes equipped with two of them!
In this tutorial, article, I'll answer some of the most commonly asked questions about the 7X CKP sensor and the 24X CKP sensor.
Contents of this tutorial at a glance:
You can find this tutorial in Spanish here: El Sensor CKP ¿Qué Es Y Para Qué Sirve? (1996-2005 3.4L V6 Chevrolet, Pontiac) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 3.4L V6 Chevrolet Impala: 2000, 2001, 2002, 2003, 2004, 2005.
- 3.4L V6 Chevrolet Monte Carlo: 2000, 2001, 2002, 2003, 2004, 2005.
- 3.4L V6 Chevrolet Lumina Minivan: 1996.
- 3.4L V6 Chevrolet Venture: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005.
- 3.4L V6 Pontiac Aztek: 2001, 2002, 2003, 2004, 2005.
- 3.4L V6 Pontiac Grand Am: 1999, 2000, 2001, 2002, 2003, 2004, 2005.
- 3.4L V6 Pontiac Montana: 1999, 2000, 2001, 2002, 2003, 2004, 2005.
- 3.4L V6 Pontiac Trans Sport: 1996, 1997, 1998.
How Many CKP Sensors Does My Car Have?
The engine management system on your 3.4L V6 Chevrolet (Pontiac) makes use of two different crankshaft position sensors. These two are the 7X CKP sensor and the 24X CKP sensors.
Here are some important specifics about each one:
- 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?
The purpose of a crankshaft position sensor is to monitor the position of the crankshaft as the engine runs.
In the 3.4L V6 engine management system, although the 7X CKP sensor and the 24X CKP sensor are tasked with monitoring the position of the crankshaft, they have two different missions. 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 ignition timing at low RPMs (usually under 2,000 RPMs).
What Happens When A CKP Sensor Goes Bad?
When a crankshaft position sensor fails, whether it is the 7X CKP sensor or the 24X CKP sensor, it will simply stop monitoring (and sending) the fuel injection computer any crankshaft position information.
A lack of the 7X CKP signal will cause a serious disturbance in the force.
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?
When the 7X CKP sensor fails:
- The engine is not going to start because the ignition control module will not activate the ignition coil packs that sit on top of it.
- The fuel injectors will not be activated.
- The following trouble code may be registered:
- P1374: 7X CKP Sensor Circuit Problem.
When the 24X CKP sensor fails:
- For the most part, the engine will still start and run. Of course the engine's not going to run optimally.
- The check engine light may be illuminated with a 24X CKP sensor trouble code:
- P0336: 24X CKP Sensor Circuit Problem
Although the fuel injection computer is designed to set a diagnostic trouble code when either CKP sensor fails, in reality it usually doesn't set one.
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?
The testing procedure for 7X CKP sensor or 24X CKP sensor is not difficult nor complicated.
This is the basic work-flow of the CKP sensor test:
- 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:
You can find the 24X CKP sensor test here (the test procedure is the same):
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.
If this info really saved the day, buy me a beer!