The camshaft position sensor in your 2.4L Frontier or XTerra is located inside the engine's distributor. If the cam sensor (which is actually the crank sensor the computer uses to activate the ignition system) goes bad, your vehicle is not gonna' start.
This article will show you how to test a 'no-start no-spark' condition caused by a bad camshaft position sensor on the 1998, 1999, 2000, 2001, 2002, 2003, 2004 Nissan Frontier or XTerra. You're only gonna' need a multimeter (no scan tool required).
OK, before you jump into the test, let me tell you that the cam sensor can not be tested with a simple resistance test. Therefore, the test presented in this article is an on-car dynamic test, done with the engine cranking.
To help you navigate this article a little easier, here are its contents at a glance:
- Important Tips And Suggestions.
- How Does The Cam Sensor Work?
- CAM SENSOR TEST 1: Verifying The Cam Sensor Is Getting Power.
- CAM SENSOR TEST 2: Verifying The 1° POS Signal.
- CAM SENSOR TEST 3: Verifying The 180° REF Signal.
You can find this tutorial in Spanish here: Sensor De La Posición Del Árbol De Levas (1998-2004 2.4L Frontier, Xterra) (en: autotecnico-online.com).
Important Tips And Suggestions
TIP 1: In the testing instructions, I'm gonna' ask you to rotate the Frontier or Xterra's engine by hand, this is important, since this is the only way to get a completely accurate result. Do not crank the engine with the starter motor.
TIP 2: The fuel system must be disabled. You can easily accomplish this by disconnecting all four fuel injectors before starting the test.
TIP 3: It's important that you test for spark first, before attempting the cam sensor test. If you have spark coming from any one of the 4 spark plug wires, then you can accurately assume the camshaft position sensor is OK.
Here's the link to the ignition coil Test: 2.4L Nissan Ignition Coil Test (98-04), which you should do first before testing the cam sensor.
TIP 4: If it turns out that the camshaft position sensor is fried, you're gonna' have to buy the whole distributor since Nissan, in all its wisdom, does not license any of the components to be sold separately.
How Does The Cam Sensor Work?
What's gonna' help you to see the 'why and how' of the testing in this article is to understand how the power transistor works.
In a nutshell, this is what happens:
The camshaft position sensor is located inside the distributor and is part of the power transistor assembly.
The cam sensor assembly is really a crank sensor, since the fuel injection computer uses it to control the creation of spark (thru') the power transistor and ignition coil.
Now, when you turn the key and crank the engine (to start it), the cam sensor/power transistor get power thru' the wire labeled with the number 5 (see photo above).
As the engine turns, the cam sensor assembly starts to create two specific position signals that it sends directly to the computer. One signal is called the 1° POS signal and the other is called the 180° REF signal.
When the computer gets these two cam signals, it does its little song and dance and shoots a Triggering signal to the power transistor.
This Triggering signal can be checked with an LED light (which you can do in: How To Test The 2.4L Frontier, XTerra Power Transistor (98-04)).
When the power transistor gets the Triggering signal from the fuel injection computer, it now starts to switch the ignition coil's power ON and OFF. This ON/OFF action is what makes the ignition coil spark and is referred to as the switching signal.
If any one of the two cam sensor signals is missing, your 2.4L Nissan Frontier (or XTerra) will crank but not start due to a lack of spark.
CAM SENSOR TEST 1: Verifying The Cam Sensor Is Getting Power
The first thing, is to check that the cam sensor (which is part of the power transistor) is getting power. You can use either a multimeter or an automotive 12 V. test light.
Alright, the following test steps assume you're using a multimeter. This is what you'll do:
Turn the dial on your multimeter to Volts DC.
With the red multimeter test lead, probe the wire labeled with the number 2, in the photo above.
Next, the Ground the black multimeter test lead directly on the battery negative (-) terminal.
Then, turn the key ON (but don't crank the engine). Your multimeter should register 12 Volts DC.
Interpreting The Results
TEST RESULT 1: Your multimeter registered 12 Volts. So far so good, since this result confirms that the camshaft position sensor is getting power. Go to: CAM SENSOR TEST 2: Verifying The 1° POS signal.
TEST RESULT 2: Your multimeter DID NOT register 12 Volts. Recheck your connections and retest.
If still no power, this is a problem (this lack of power) that will make your Nissan Frontier or Xterra not start (since without this voltage, the camshaft position sensor is not gonna' work).
Although it's beyond the scope of this article to troubleshoot this missing voltage, finding the cause of these missing 12 Volts will solve your 'no-spark no-start' condition on your 2.4L Nissan Frontier or Xterra.