Circuit/System Testing
WARNING: This page is about a different car, the 2008 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 the MGU X2 and the SGCM X2 connectors. Refer to Generator with Starter Replacement and Generator Control Module Replacement .
- Test the circuits in the SGCM to MGU Terminal Reference Table as indicated below. Also check these circuits for short to ground.
- If any of the circuits are not within specification, check for an open/high resistance or short to ground.
- Reconnect SGCM connector X2.
- Test the circuits in the MGU to SGCM Specification Table to ground as indicated below.
- If any of the circuits are not within the specified range, replace the SGCM.
- Reconnect the MGU X2 connector and disconnect the SGCM X2 connector. Refer to Generator with Starter Replacement and Generator Control Module Replacement .
- Test the circuits in the SGCM to MGU Specification Table as indicated below.
- If all circuits test normal, replace the MGU.
SGCM to MGU Terminal Reference Table
| MGU Connector/Terminal | SCGM Connector/Terminal | Minimum Resistance | Maximum Resistance |
|---|---|---|---|
| Harness Continuity Test | |||
| B | X2/7 | - | less than 1 ohm |
| C | X2/6 | - | less than 1 ohm |
| D | X2/4 | - | less than 1 ohm |
| E | X2/17 | - | less than 1 ohm |
| F | X2/20 | - | less than 1 ohm |
| G | X2/19 | - | less than 1 ohm |
| H | X2/5 | - | less than 1 ohm |
MGU to SGCM Specification Table
| MGU Connector/Terminal | Signal Name | Minimum Resistance | Maximum Resistance |
|---|---|---|---|
| Measurements made to ground. SGCM connected and MGU disconnected. | |||
| D | REZ- | 1.6k ohms | 2k ohms |
| H | REZ+ | 1.6k ohms | 2k ohms |
| C | REZ3 | Over 1 M ohm | - |
| B | REZ4 | Over 1 M ohm | - |
| E | REZGS (GND) | - | less than 5 ohm |
| G | REZ1 | Over 1 M ohm | - |
| F | X2/5 | Over 1 M ohm | - |
SGCM to MGU Specification Table
| SGCM Connector/Terminal | SGCM Connector/Terminal | Minimum Resistance | Maximum Resistance |
|---|---|---|---|
| MGU connected and SGCM disconnected. | |||
| X2/4 | X2/5 | 20.1 ohms | 26.7 ohms |
| X2/6 | X2/19 | 32.4 ohms | 43.0 ohms |
| X2/7 | X2/20 | 32.9 ohms | 43.5 ohms |
| X2/4 | X2/6 | Over 1 meg ohm | - |
| X2/4 | X2/7 | Over 1 meg ohm | - |
| X2/6 | X2/7 | Over 1 meg ohm | - |