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P1A79 Cadillac Code - Starter/Generator Control Module Coolant Temperature Sensor 3 Circuit Low Voltage

Quick Answer

The Starter/Generator Control Module (SGCM) monitors its internal fluid temperature sensors to control the SGCM coolant pump and SGCM cooling fan. Common causes include 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. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1A79 Cadillac indicates Starter/Generator Control Module Coolant Temperature Sensor 3 Circuit Low Voltage.
Common causes: Common causes include 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.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 754

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Feb 22, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1A79 Cadillac 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 P1A79 Cadillac - Starter/Generator Control Module Coolant Temperature Sensor 3 Circuit Low Voltage - AutoCodes.com — P1A79 Cadillac Code - Starter/Generator Control Module Coolant Temperature Sensor 3 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1A79 Cadillac?

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

How to Fix the DTC P1A79 Cadillac?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1A79 Cadillac code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1A79 Cadillac Code

What does the OBDII code P1A79 mean for my Cadillac?

P1A79 indicates a low voltage issue with the Starter/Generator Control Module Coolant Temperature Sensor 3.

What are the common symptoms of the P1A79 code?

Symptoms may include warning lights on the dashboard, reduced engine performance, or issues with the hybrid system if applicable.

What could cause the P1A79 code to trigger?

Causes may include a faulty coolant temperature sensor, damaged wiring, poor electrical connections, or issues with the Starter/Generator Control Module itself.

How can I diagnose the P1A79 code?

Start by checking the coolant temperature sensor and its wiring for damage, ensure electrical connections are secure, and use a scan tool to monitor sensor readings.

What steps can I take to repair the P1A79 code?

Repair options include replacing the faulty coolant temperature sensor, repairing any damaged wiring, and ensuring all connections are clean and secure.

Is it safe to drive my Cadillac with the P1A79 code?

While it may be safe for short distances, it is advisable to address the issue promptly to avoid potential engine or hybrid system damage.

Can I reset the P1A79 code after repairs?

Yes, you can reset the code using an OBDII scanner, but ensure that the underlying issue has been resolved to prevent the code from returning.

How much will it cost to fix the P1A79 code?

Repair costs can vary widely based on the specific issue, ranging from a simple sensor replacement costing around $100 to more complex electrical repairs that could exceed $500.

Should I take my Cadillac to a dealer for the P1A79 code?

While dealerships have specialized knowledge of Cadillac vehicles, a qualified independent mechanic can often diagnose and repair the issue effectively as well.