P1A77 - Starter/Generator Control Module Coolant Temperature Sensor 2 Circuit High Voltage

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3   
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P1A77 Possible Causes

  • Faulty Starter/Generator Control Module (SGCM)
  • Starter/Generator Control Module (SGCM) harness is open or shorted
  • Starter/Generator Control Module (SGCM) circuit poor electrical connection

First diagnose P1A77 code

    Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.

Cost of diagnosing the P1A77 code

    Labor: 1.0

    The cost of diagnosing the P1A77 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

P1A77 Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P1a77 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.
OBDII Code P1a77 - Starter/Generator Control Module Coolant Temperature Sensor 2 Circuit High Voltage - AutoCodes.com

P1A77 More Information

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P1A77 Information for specific makes

  • P1A77 BUICK Starter/Generator Control Module Coolant Temperature Sensor 2 Circuit High Voltage
  • P1A77 CADILLAC Starter/Generator Control Module Coolant Temperature Sensor 2 Circuit High Voltage
  • P1A77 CHEVROLET Starter/Generator Control Module Coolant Temperature Sensor 2 Circuit High Voltage
  • P1A77 GMC Starter/Generator Control Module Coolant Temperature Sensor 2 Circuit High Voltage
  • P1A77 SATURN Starter/Generator Control Module Coolant Temperature Sensor 2 Circuit High Voltage

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