How To Test The Cam Sensor 2.4L Nissan Frontier, XTerra (1998-2004)

TEST 2: Verifying The 1° POS Signal

If you read the section How Does The Cam Sensor Work, you know that the cam sensor produces two cam signals.

One cam signal is called the 1° POS signal and the other is called the 180° REF signal. Both of these can be very easily and accurately tested with a multimeter in Volts DC mode.

This particular test will help you to test the 1° POS signal.

OK, these are the test steps:

1. 1

   Locate the wire labeled with the number 3 (see photo above).

2. 2

   Connect the red multimeter test lead to this wire using an appropriate tool (like a wire piercing probe).
   
   The distributor's connector must remain connected.

3. 3

   Next, Ground the black multimeter test lead to the battery negative (-) terminal.

4. 4

   When you have everything set up, turn the engine by hand using the appropriate tools as you observe your multimeter's display.
   
   Remember, the fuel injectors should be disabled, and this can be accomplished by disconnecting them from their electrical connector.

5. 5

   Your multimeter should register four pulses of 5 Volts per one full turn of the crankshaft pulley.
   
   The cam sensor's 1° POS signal is an ON/OFF voltage signal. ON is when your multimeter should register 5 Volts, and OFF is when it'll register 0 Volts.

Let's find out what your test result means:

CASE 1: The multimeter registered the ON/OFF 5 Volt pulse. So far so good, since this is the correct and expected test result.

The next step is to check that the camshaft position sensor is producing a good 180° REF signal. Go to: TEST 3: Verifying The 180° REF Signal.

CASE 2: The multimeter DID NOT register the ON/OFF 5 Volt pulse. Recheck your multimeter connections and repeat the test.

If the multimeter still does not register the ON/OFF 5 Volt pulse, then the camshaft position sensor is bad and needs to be replaced.

What sucks about this, is that the camshaft position sensor is not sold separately and you'll need to replace the whole distributor.

TEST 3: Verifying The 180° REF Signal

This test will check/confirm that the camshaft position sensor is producing the 180° REF signal that the fuel injection computer needs to start your 2.4L Nissan Frontier (or Xterra).

The 180° REF signal will also be tested with your multimeter in Volts DC, once again.

Let's get started:

1. 1

   Connect the red multimeter test lead to the wire (circuit) labeled with the number 4 in the image above (using an appropriate tool like a wire-piercing probe).
   
   The distributor's connector must remain connected.

2. 2

   Next, Ground the black multimeter test lead to the battery negative (-) terminal.

3. 3

   When everything has been set up, turn the engine by hand (just as you did in TEST 2) using the appropriate tools as you observe the multimeter.
   
   Remember, the fuel system should be disabled. The easiest way to do this is to disconnect the fuel injectors from their electrical connector.

4. 4

   Your multimeter should register an ON/OFF 5 Volt pulse, just like in the previous test (when you were testing the 1° POS signal in CAM SENSOR 2) except that you'll see a whole more of these pulses.
   
   The cam sensor's 180° REF signal is an ON/OFF voltage signal. ON is when your multimeter should register 5 Volts, and OFF is when it'll register 0 Volts.

Let's find out what your test result means:

CASE 1: The multimeter registered the ON/OFF 5 Volt pulse. This is the correct and expected test result and means that the camshaft position sensor is producing a good 180° REF signal.

Now, if in TEST 2, you confirmed that the camshaft position sensor is producing the 1° POS signal, the test result you just got from this test, confirms that the camshaft position sensor is working fine, and not the cause of your Nissan Altima's 'no-spark no-start' problem.

On the other hand, if in TEST 2, you confirmed that the camshaft position sensor is NOT producing the 1° POS signal, and you did get a 180° REF signal with this test, this means that the camshaft position sensor is fried (you'll need to replace the whole distributor, since the camshaft position sensor is not sold separately).

CASE 2: The multimeter DID NOT register the ON/OFF 5 Volt pulse. Recheck your multimeter connections and retest.

If you still do not see the ON/OFF 5 Volt pulse, then the camshaft position sensor is bad.

Since the camshaft position sensor is not sold separately, you'll need to replace the whole distributor.