How to Test an Ignition Control Module with a Multimeter

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Have you noticed engine performance issues in your vehicle? Has your engine started stalling? Will your car suddenly, not start? Or will your car’s engine not spark? If so, then most probably your engine ignition control module is bad or failing. This situation does not need a course of alarm, as I will take you through on ways to test your ignition module.

​The ignition module, or the ESC module, together with the computers in your car, work to time your engine ignition system to ensure the best performance and efficiency. Most of us know little or nothing at all when it comes to working our way around an engine, and so, before learning how to test an ignition module, we need to check ignition modules using these simple steps.

​Signs that show your ignition model needs testing

1. Engine light is on

The ESCM monitors and controls all the parts of your vehicle, including the ignition system. It will turn on the engine check lights if it discovers your ignition modules have a problem.

2. Engine is misfiring

An engine misfires due to a lack of complete combustion. An ignition module that has a problem or that is faulty is a key reason for incomplete combustion.

3. Stalling

A faulty ignition module will prevent your engine from getting sparks, which cause stalling.

4. Car won’t start

If your ignition module has failed, this means your car won’t start.

5. Trouble powering up the accessories

Turning the key to the “running position” is likely to power the accessories, but if this does not happen, there must be a fault within your ignition modules.

Tools required:

A multimeter

There exists two types of multimeters which include:

1. Analog multimeters

Before the digital multimeter came into existence was the analog multimeters. Despite being the cheapest among the multimeters, they are bit difficult to read.

2. Digital multimeter

This multimeter is user friendly and also the most common used multimeter in today’s market.

Unlike the analog multimeter, digital multimeter gives a more accurate reading.

The digital multimeters are categorized into three main basic types namely:

auto-ranging multimeter

This is the most costly of all multimeters and also the best to use in terms of accuracy.

fluke multimeter

This is among the most available of the digital multimeters and preferred due to its large-sized display screen.

clamp digital multimeter

this multimeter is mostly preferred due to the different setting types available. The user can choose the best and appropriate setting to measure with.

When it comes to testing your ignition control module, a digital multimeter is more preferred over the analog one. Its two key functions are:

Measuring voltage

Measuring continuity and resistance in circuits and electrical components


​This can be achieved by:

  1. ​Removing one plug from your spark plug
  2. Then insert any old spark plug into your plug boot’s end.
  3. While doing this, make sure to place your vehicle’s spark plug on top of any metal surface on your engine.
  4. Crank your vehicle’s engine while checking for any sparks that might appear in the inserted old spark plug.
  5. No spark indicates a problem with your ignition.

After this first process, the multimeter will be of use for the processes to follow, so make sure your multimeter is in perfect working condition. This will ensure accurate readings avoiding errors.


Coils normally have both positive and negative terminals. These are the processes to follow in this step:

  1. First, you need to check for voltage in your vehicle coil’s positive terminal while your car’s ignition key is turned on. This will require placing the multimeter’s red lead on your vehicle’s coil’s negative terminal.
  2. After that, place the black lead to the battery negative terminal.
  3. You need to turn the ignition key on and leave it at the “runs position.”

After that, the multimeter should be able to read your battery positive terminal’s voltage. If there is no voltage present, it means your ignition switch or the ignition wiring circuits has a problem.


The first thing you do in this step is:

  1. locating the positive (+) ignition module wire.
  2. You need to turn your car’s key to run position but do not start the engine.
  3. Pierce your car’s positive ignition module wire with the red lead of the multimeter. The wire should have a battery voltage reading. If this doesn’t happen and no battery voltage reading shows, you need to check for open circuits between the wires and ignition switch.
  1. The first thing will be locating the negative (-) ignition module wire.
  2. Pierce your car’s negative ignition module wire with the red lead of the multimeter.
  3. You will need to remove your car’s distributor cap, but avoid removing the spark plug wires.
  4. The next step will be rotating the distributor center shaft by using your hand, or you can do this by cranking your car’s engine. When doing this, you will need to observe the distributor rotor while your car’s engine gets cranked over, or the rotor is being rotated by hand.

If it happens that the distributor rotor does not turn, then this means that the distributor or the distributor’s gear is faulty.

The multimeter voltage reading should be between zero and the battery voltage.

Your final process or step if the multimeter reading does not range between zero and the battery voltage while your car’s distributor is turning should be to have your ignition modules replaced.

For those of you who are not very good at working on the engine, the process of replacing your ignition module should range between USD 272 and USD 380. You should pay approximately USD 65 and USD 83 for the labor cost. The price of the parts should be between USD 207 and USD 297.

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