Testing CS Generators Without GM Tester Tool

Testing the CS Generator without the GM Tester Tool

Remember, the CS Generator only needs 2 wire connections and a good ground to make it work. Information About CS Generators


1. Make sure the generator has a good ground and the Batt connection at the generator is good and shows battery voltage.
2. Disconnect 4-wire connector from generator.
3. With ignition ON and engine OFF, check for approx Batt voltage in cavity B of the harness connector with a good DVOM.

Note: This circuit is what turns the generator ON. It is a resisted circuit and is usually energized by the PCM through an internal resistor when the key is turned to Run.

4. If the DVOM shows approx Batt voltage in cavity B and the checks in step 1 are good, there is a problem with the generator.

Note: Checking cavity B with the 4-wire connector plugged into the generator and engine not running might show little or no Volts even with a properly functioning generator. This circuit is a ground in the generator until the generator begins producing power. The circuit then turns positive.

5. If the DVOM shows NO voltage in cavity B, there is a problem upstream of the generator.
a. Review the charging system wiring diagram and Check:
b. Wire problems between generator and PCM.
c. Connection problems at PCM.
d. Battery and Ignition power supplies at PCM.