Circuit/System Testing

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.

Disconnect starter/generator control module (SGCM) connector C2. Refer to Generator Control Module Replacement .
Test the circuits in the SGCM to MGU Specification Table from the C2 connector to ground.
- If all of the circuits are within the minimum or maximum values specified, replace the SGCM.
Disconnect the MGU 10-pin connector. Refer to Generator with Starter Replacement .
Test the circuits in the SGCM to MGU Terminal Reference Table for an open, short to ground or high resistance.
- If all circuits test normal, replace the MGU.

SGCM to MGU Specifications

SGCM Connector/Terminal	Signal Name	Minimum Resistance	Maximum Resistance
C2/4	REZ-	1.6 K ohm	2 k ohm
C2/5	REZ+	1.6 K ohm	2 k ohm
C2/6	REZ3	Over 1 meg ohm	-
C2/7	REZ4	Over 1 meg ohm	-
C2/17	REZGS (GND)	-	less than 5 ohm
C2/18	REZGS (GND)	-	less than 5 ohm
C2/19	REZ1	Over 1 meg ohm	-
C2/20	REZ2	Over 1 meg ohm	-

SGCM to MGU Terminal Reference

MGU 10 Pin Connector/Terminal	SCGM Connector/Terminal	Minimum Resistance	Maximum Resistance
B	C2/7	-	less than 1 ohm
C	C2/6	-	less than 1 ohm
D	C2/4	-	less than 1 ohm
E	C2/17 and 18	-	less than 1 ohm
F	C2/20	-	less than 1 ohm
G	C2/19	-	less than 1 ohm
H	C2/5	-	less than 1 ohm