This tutorial is not intended to diagnose a CPS that is failing intermittently, although it might be useful for that purpose. Read this entire tutorial before attempting to perform the tests in this tutorial. Please click here and read our disclaimer before using this tutorial.
This tutorial is intended for Reatta owners who have experience in working with hand tools and are familiar with the safety practices related to working around the moving parts of an engine. All safety precautions should be strictly adhered to.
- Analog or Digital Multimeter .
- Wire piercing probe attachment for multimeter lead or long sharp pin. (see photo below)
- CPS Tester (Instructions for building it can be found here.)
- Contact cleaner for cleaning wires.
- 1-1/8" socket and ratchet.
Before you begin the tests:
- Make sure the battery is in good condition and fully charged. A low battery could affect test results.
- Clean wires at Ignition Control Module (ICM) connector and remove tape if needed to be able to see wire colors.
This tutorial requires piercing the insulation of the wires going into the ICM . Be very careful not to damage the wires. An alternate method may be used as long as you can connect the meter and tester as described in each test. If you don't feel comfortable about piercing the wires do not proceed with this tutorial. Please see the chart at the bottom of this page for references to wiring colors and designations.
The following tests should be performed in sequence.
TEST 1 - Spark
Test for spark from the coils
- Remove a spark plug wire .
- Check for a good spark while an assistant attempts to start the engine.
(The spark should be blueish white and jump at least 1/2" to ground.)
Do you have fire to the spark plugs?
YES - Stop here! The CPS or ICM is not the reason the engine will not start.
NO - Continue to TEST 2.
Wiring diagram for reference