Circuit Description
The starter/generator control module (SGCM) monitors its internal fluid temperature sensors to control the SGCM coolant pump and SGCM cooling fan. The internal fluid temperature sensors of the SGCM are thermistors and are not serviceable. When the internal fluid temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the internal fluid temperatures are hot, the resistances of the sensors are low and the voltage signals are low. The input parameters are not displayed on the scan tool. The SGCM calculates the estimated temperature of the electronics to interpret the total temperature of the SGCM. This value is displayed on the scan tool.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1A7E Starter/Generator Control Module Overtemperature High Voltage System Disabled
Conditions for Running the DTC
| • | The engine has been running for 30 seconds. |
| • | The SGCM has received voltage on the ignition 0 voltage circuit. |
| • | The SGCM has turned ON and no configuration DTC are present. |
Conditions for Setting the DTC
The SGCM calculated temperature is over 110°C (230°F).
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
| • | The SGCM shuts down and system will run on 12 volt system only. |
Conditions for Clearing the DTC
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
If there is a restriction of the air flow through the radiator this DTC may set. Ensure that the vehicle front end has at least 1.5 meters (5 feet) of clearance from obstructions to airflow if vehicle is parked.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Is the DTC set as current DTC? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections |
3 | Inspect the SGCM coolant level. Is the SGCM coolant level low? | Go to Step 4 | |
4 | Inspect the vehicle front end for obstructions to the radiator. Did you find and correct the condition? | Go to Step 10 | Go to Step 5 |
5 | With a scan tool, command the cooling fan ON and OFF. Does the cooling fan turn ON and OFF with each command? | Go to Step 6 | Go to Cooling Fan Inoperative |
6 | With a scan tool, command the SGCM Coolant Pump ON and OFF. Does the SGCM coolant pump turn ON and OFF with each command? | Go to Step 7 | Go to Starter Generator Control Module Coolant Pump Inoperative |
7 |
Does the SGCM coolant circulate when the SGCM pump is ON? | Go to Step 8 | Go to Generator Control Module Cooling System Draining and Filling |
8 | Inspect for poor connections at the harness connector of the SGCM . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
9 | Replace the SGCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
