AutoCodes – GMC – P248A GMC

P248A GMC Code - Reductant Heater 1 Feedback Circuit Low Voltage

Quick Answer

As reductant will freeze at temperatures below -11°C (12°F), there are 2 reductant heaters located in the reductant tank. Common causes include Faulty Reductant Line Heater, Reductant Line Heater harness is open or shorted, Reductant Line Heater 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: P248A GMC indicates Reductant Heater 1 Feedback Circuit Low Voltage.
Common causes: Common causes include Faulty Reductant Line Heater, Reductant Line Heater harness is open or shorted, Reductant Line Heater 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 1,022

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 29, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P248A GMC Description

As reductant will freeze at temperatures below -11°C (12°F), there are 2 reductant heaters located in the reductant tank. One heats the reductant in the tank, and one heats the reductant supplied to the reductant injector supply pipe. The Engine Control Module (ECM) monitors the reductant temperature in the tank in order to determine if the reductant temperature is below its freeze point. If the ECM determines that the reductant may be frozen, it activates a defrost strategy energizing the reductant heater. This energizing action terminates when the temperature sensor measures a threshold value over which the heater must be deactivated. The Diagnostic Trouble Code (DTC) will be set when there is greater than a 3 V difference between battery voltage and reductant tank heater voltage.

OBDII Code P248A GMC - Reductant Heater 1 Feedback Circuit Low Voltage - AutoCodes.com — P248A GMC Code - Reductant Heater 1 Feedback Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P248A GMC?

Faulty Reductant Line Heater
Reductant Line Heater harness is open or shorted
Reductant Line Heater circuit poor electrical connection
Faulty Reductant Pump and Sensor Assembly
Faulty Reductant Control Module

How to Fix the DTC P248A GMC?

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 P248A GMC 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 P248A GMC Code

1. What are the common symptoms of OBDII code P248A GMC?

- Common symptoms include the check engine light turning on, reduced engine performance, and potential issues with the exhaust system.

2. What can cause the OBDII code P248A GMC to trigger?

- This code is typically triggered by a malfunction in the Reductant Heater 1 Feedback Circuit, resulting in low voltage being detected.

3. How serious is the OBDII code P248A GMC?

- While the code itself may not cause immediate harm to the vehicle, prolonged driving with this issue can lead to increased emissions and potential damage to the exhaust system.

4. How can I diagnose the cause of OBDII code P248A GMC?

- Diagnosing this code often involves checking the Reductant Heater 1 Feedback Circuit for shorts, open circuits, or other electrical issues using a multimeter.

5. Can I continue driving with the OBDII code P248A GMC active?

- It is not recommended to continue driving with this code active, as it may lead to increased emissions and potential damage to the exhaust system over time.

6. How can I repair OBDII code P248A GMC?

- Repairing this code typically involves troubleshooting the Reductant Heater 1 Feedback Circuit, checking for faulty wiring or connections, and replacing any damaged components as necessary.

7. Can a DIY enthusiast fix OBDII code P248A GMC?

- While some DIY enthusiasts may be able to diagnose and repair this code, it is recommended to seek professional help, especially when dealing with electrical components.

8. Is there a way to prevent OBDII code P248A GMC from recurring?

- Regular maintenance, such as checking the exhaust system and monitoring the reductant heater circuit, can help prevent this code from recurring in the future.

9. What is the typical cost to repair OBDII code P248A GMC?

- The cost to repair this code can vary depending on the extent of the issue and the specific repairs needed, but it may range from a few hundred to over a thousand dollars.

10. Can OBDII code P248A GMC affect the vehicle's fuel efficiency?

- Yes, this code can potentially affect the vehicle's fuel efficiency due to disruptions in the reductant system, leading to suboptimal emissions control.