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:
You can find this tutorial in Spanish here: Cómo Probar El Módulo De Encendido (1992-1994 2.4L Nissan D21 Pickup) (at: autotecnico-online.com).
The following tutorials may come in handy:
- How To Test The Ignition Coil 1992-1994 Nissan D21 Pickup.
- How To Test The Crank Angle Sensor (1990-1996 2.4L Nissan 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 and you can find 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
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.
Where To Buy The Power Transistor (Ignition Control Module)
Yup, the Nissan D21 power transistor can get expensive. Check out the following links and comparison shop:
TEST 1: Making Sure The Power Transistor Is Getting Ground
The first thing we'll do, to get this show on the road is to make sure the power transistor is getting Ground.
Chassis Ground is fed to the power transistor by the black (BLK) wire of the power transistor's 3-wire connector.
Alright, let's get going:
- 1
Disconnect the power transistor from its electrical connector.
- 2
Connect the black multimeter test lead to the BLK wire of the power transistor's electrical connector. This is the middle wire of the connector.
- 3
Connect the red multimeter test lead to the battery positive (+) terminal.
- 4
Your multimeter should read 10 to 12 Volts DC if the power transistor is getting Ground.
Let's take a look at what your test results mean:
CASE 1: The power transistor is getting Ground. This is the correct and expected test result.
The next step is to make sure the power transistor is getting a triggering signal from the fuel injection computer. For this step, go to: TEST 2: Making Sure The Power Transistor Is Being Triggered.
CASE 2: The power transistor IS NOT getting Ground. This tells you that the power transistor is not working due to a lack of Ground.
Your next step is to repair and restore Ground to the connector. Once the Ground circuit is restored, the power transistor should function again.