The camshaft position sensor, which is inside the distributor, can be tested with an LED light. In this tutorial I'll show you how to do it step-by-step.
With your test results you'll be able to find out if it's defective or not.
NOTE: The camshaft position sensor in the 1990-1995 Pathfinder and Pick Up is also known as the crankshaft position sensor (altough it's located in the distributor).
Contents of this tutorial at a glance:
- Important Tips And Suggestions.
- How Does The Cam Sensor Work?
- TEST 1: Making Sure The Cam Sensor Is Getting Power.
- TEST 2: Making Sure The Cam Sensor Is Getting Ground.
- TEST 3: Testing The 120° REF Signal.
- TEST 4: Testing The 1° POS Signal.
- Where To Buy The Distributor And Save.
- More Nissan 3.0L V6 Tutorial.
You can find this tutorial in Spanish here: Cómo Probar El Sensor De La Posición Del Árbol De Levas (1990-1995 3.0L Pathfinder y Pick Up) (at: autotecnico-online.com).
This tutorial applies to the following vehicles:
- 3.0L V6 Nissan Pathfinder: 1990, 1991, 1992, 1993, 1994, 1995.
- 3.0L V6 Nissan D21 Pick Up: 1990, 1991, 1992, 1993.
- 3.0L V6 Nissan Pick Up: 1994, 1995.
You can find the ignition system wiring diagram for the 3.0L V6 Pathfinder and Pick Up here:
Important Tips And Suggestions
TIP 1: Don't use the starter motor to turn the engine in TEST 3 and TEST 4. It's important to turn the engine by hand using a 1/2" ratchet wrench and socket on the crankshaft pulley. The tests will give the correct test result only if you turn the engine by hand.
TIP 2: The fuel system must be disabled before you do TEST 3 and TEST 4. You can easily do this by removing the fuel pump fuse.
The fuel pump fuse location:
- 1990-1995 3.0L Pathfinder: fuse H of the dash fuse box.
- 1990-1995 3.0L Pick Up: fuse H of the dash fuse box.
TIP 3: Before you test the camshaft position sensor, you must first test the ignition coil. If the ignition coil sparks then you can conclude that the camshaft position sensor is good and functioning correctly and therefore you don't need to test it.
The ignition coil test is not hard to and you can find it here: How To Test The Ignition Coil And Power Transistor (1990-1995 Pathfindier And Pick Up).
TIP 4: If the camshaft position sensor is bad, 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?
Here's a very brief description of how the camshaft position sensor works:
- The camshaft position sensor is located inside the distributor and its job is to tell the fuel injection computer the positions of the pistons (especially the position of piston #1).
- The cam sensor assembly is really a crankshaft position sensor, since the fuel injection computer uses it to control the creation of spark (thru') the power transistor and ignition coil.
- When you turn the key and crank the engine (to start it), the camshaft position sensor gets 12 Volts thru' the black with white stripe (BLK/WHT) wire of the distributor's 4-wire connector.
- As the engine turns, the camshaft position sensor 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 120° REF signal.
- When the computer gets these two signals, it sends an activation signal to the power transistor.
- When the power transistor gets its activation signal from the fuel injection computer, it now starts to switch the ignition coil's power ON and OFF.
- With this ON/OFF signal the ignition coil starts to spark.
When the camshaft position sensor fails on your 3.0L Nissan Pathfinder or Pick Up; the engine is not going to start due to a lack of spark.
You're also going to see a trouble code 11: Crankshaft Position (CKP) Sensor registered in the fuel injection computer. This code will light up the check engine light on your Nissan's instrument cluster.
TEST 1: Making Sure The Cam Sensor Is Getting Power
The camshaft position sensor gets 12 Volts from the black with white stripe (BLK/WHT) wire of its 4-wire connector.
In the photo above, this wire connects to the female terminal labeled with the number 2. This female terminal belongs to the engine wiring harness connector.
We're gonna' do a simple multimeter voltage test to check the presence of these 12 Volts.
These are the test steps:
Set your multimeter to Volts DC mode.
Disconnect the 4 wire connector from the distributor.
Probe the female terminal labeled with the number 2 with the red multimeter test lead.
NOTE: Be careful not to damage the female terminal of the connector with the red multimeter test lead.
Connect the black multimeter test lead directly on the battery negative (-) terminal.
Turn the key on but don't crank the engine.
Your multimeter should register 10 to 12 Volts DC.
Let's examine your test result:
CASE 1: Your multimeter registered 10 to 12 Volts. This is the correct test result and lets you know that the camshaft position sensor is getting power.
In the next test we're gonna' check for the presence of Ground in the female terminal labeled with the number 3. For this test go to: TEST 2: Making Sure The Cam Sensor Is Getting Ground.
CASE 2: Your multimeter DID NOT register 10 to 12 Volts. Without this voltage the camshaft position sensor will not function and if it does not function the fuel injection computer will not activate the ignition coil.
Although it's beyond the scope of this tutorial your next step is to find out why this voltage is missing and repair the problem. The following wiring diagram will help you: Ignition System Wiring Diagram (1990-1995 3.0L Nissan Pick Up And Pathfinder ).