How To Test The Power Transistor 1992, 1993, 1994 Nissan D21 Pickup

When the power transistor (ignition control module) on your 1992, 1993, or 1994 2.4L Nissan D21 fails, the engine is not gonna' start due to a lack of spark.

The cool thing is that testing the power transistor can be done in 2 simple tests and in this tutorial I'll explain just how.

Contents of this tutorial at a quick glance:

  1. Test The Ignition Coil First.
  2. Power Transistor Circuit Descriptions.
  3. TEST 1: Making Sure The Power Transistor Is Getting Ground.
  4. TEST 2: Making Sure The Power Transistor Is Being Triggered.
  5. Where To Buy The Power Transistor (Ignition Control Module).

The following tutorials may come in handy:

  1. How To Test The Ignition Coil 1992-1994 Nissan D21 Pickup.
  2. How To Test The Power Transistor 1992-1994 Nissan D21 Pickup.

Test The Ignition Coil First

Before you start with the power transistor test in this tutorial, you should first eliminate the ignition coil as defective. This is an important first step.

Testing the ignition coil, on the 2.4L Nissan D21 Pickup is super easy! I've written up a tutorial on how to do it here: How To Test The Ignition Coil 1992-1994 Nissan D21 Pickup.

If you have already made sure that the ignition coil is not behind the 'no start no spark' problem, then proceed.

Power Transistor Circuit Descriptions

How To Test The Power Transistor 1992, 1993, 1994 Nissan D21 Pickup

The power transistor (ignition control module) has 3 wires coming out of its connector. Each one has a specific job to do and here's a brief description of each:

NOTE: To further help you in your diagnostic tests, you can find the 1992-1994 2.4L Nissan D21 ignition system wiring diagram here: 1992-1994 2.4L Nissan D21 Pickup Ignition System Wiring Diagram.


1992-1994 2.4L Nissan D21 Power Transistor Connector
Pin Wire Color Description
1 White (or white with black stripe wire) -Power Transistor Trigger Signal
2 Black -Ground
3 Blue -Ignition Coil Control Signal

NOTE: Your 2.4L Nissan D21's power transistor harness connector has female metal terminals. You'll need to use a back probe or a wiring piercing probe to test the signals in the wires.