This tutorial will explain how to test the crankshaft position (CKP) sensor on the 2002-2004 4.2L Olds Bravada and on the 2004-2007 4.2L Buick Rainier with a multimeter.
With your test results, you will quickly and easily determine if the CKP sensor is good or bad.
Contents of this tutorial:
This tutorial applies to the following vehicles:
- 4.2L Oldsmobile Bravada: 2002, 2003, 2004.
- 4.2L Buick Rainier: 2004, 2005, 2006, 2007.
Symptoms Of A Bad CKP Sensor
The CKP sensor's job is to inform the PCM of the crankshaft position as the engine is cranking or running.
With this vital information, the PCM activates and controls the ignition system and fuel system components needed to start and keep the engine running optimally.
When the CKP sensor fails and stops providing crankshaft position info to the PCM, the PCM will set one of the following diagnostic trouble codes:
- P0335: Crankshaft Position (CKP) Sensor Circuit Failure.
- P1335: Crankshaft Position (CKP) Sensor Circuit Failure With The Engine Running.
The CKP sensor is known to fail intermittently. In other words, it'll work fine most of the time, but then it won't.
If your 4.2L Oldsmobile Bravada (Buick Rainier) is experiencing an intermittent no-start problem, you'll need to test the CKP sensor when the engine is not starting. Otherwise, the CKP sensor will always test good.
Where To Buy A CKP Sensor And Save
The following links will help you comparison shop for the CKP sensors of known Automotive Brands (no knock off sensors):
Important 4.2L CKP Sensor Testing Suggestions
The only thing that complicates testing the CKP sensor is its location bellow the starter motor.
The three options, ranked from easiest to hardest, you have when testing the CKP sensor are:
- Just replace it.
- Remove it and bench test it.
- On-car CKP sensor's performance test.
OPTION 1: Replacing the CKP sensor without testing it to see if the problem goes away seems to be the de facto way of diagnosing the CKP sensor for many. For most folks, this makes sense for two simple reasons:
- The CKP sensor is not an expensive component.
- The CKP sensor is in an inaccessible testing location.
OPTION 2: If you need to make sure the CKP is bad (before replacing it), the quickest and easiest way to find out is to remove it and bench-test it. TEST 1 explains how to do this in detail.
This method still has its possible complications because the CKP sensor or its rubber seal may get damaged/destroyed when removing it. If this happens, you'll need to replace the CKP sensor even if it tests good.
OPTION 3: The on-car performance test of the CKP sensor is a bit more involved. In a nutshell, you would have to:
- Buy a CKP sensor pigtail connector (online or at your local auto parts store).
- Connect the pigtail connector to the CKP sensor.
- Connect your multimeter to this pigtail connector.
- Crank the engine.
- See if the multimeter reports an AC voltage.
In TEST 2, you'll find the on-car performance test of the CKP sensor described in detail.
TEST 1: Checking CKP Sensor Resistance With A Multimeter
Usually, when the CKP sensor fails, it'll suffer an internal short-circuit or an open-circuit problem.
You and I can easily confirm if the CKP sensor has suffered one of these two conditions by performing a multimeter resistance test on it.
If the CKP sensor is OK, your multimeter should report it having a resistance of 500 to 900 Ohms.
IMPORTANT: You'll need to raise your vehicle and place it on jack stands to access the CKP sensor. Don't trust the jack alone to keep the vehicle up in the air while you work underneath it.
Let's get started:
Disconnect the CKP sensor from its electrical connector.
LOCATION: The CKP sensor is located next to the starter motor.
Remove the CKP sensor.
Place your multimeter in Ohms mode.
Probe the male spade terminals of the CKP sensor with the multimeter test leads.
You should see a resistance of 500 to 900 Ohms.
Let's take a look at what your test results mean:
CASE 1: The CKP sensor's resistance is within specification. This is the correct and expected test result and it tells you that the CKP sensor is OK.
Although not necessary, you can further confirm the CKP sensor is good by performing TEST 2. Go to: TEST 2: Testing The CKP Sensor's Output With A Multimeter.
CASE 2: The CKP sensor's resistance IS NOT within specification. This test result confirms that the crankshaft position sensor is bad and needs replacement.
Although not necessary, you can further confirm the CKP sensor is bad by performing TEST 2. Go to: TEST 2: Testing The CKP Sensor's Output With A Multimeter.