AutoCodes – Generic – P248B

P248B Code - Reductant Heater 1 Feedback Circuit High 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: P248B indicates Reductant Heater 1 Feedback Circuit High 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 808

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 P248B 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 P248B - Reductant Heater 1 Feedback Circuit High Voltage - AutoCodes.com — P248B Code - Reductant Heater 1 Feedback Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P248B?

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 P248B?

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 P248B 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.

Need more information about the P248B code?

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Need Help with the Code?

Get the P248B code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P248B Buick — Reductant Heater 1 Feedback Circuit High Voltage
P248B Cadillac — Reductant Heater 1 Feedback Circuit High Voltage
P248B Chevrolet — Reductant Heater 1 Feedback Circuit High Voltage
P248B GMC — Reductant Heater 1 Feedback Circuit High Voltage

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 P248B Code

1. What are the common symptoms of OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage)?

The common symptoms of P248B may include the check engine light being illuminated, reduced engine performance, and potential issues with the vehicle's emissions system.

2. What are the possible causes of OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage)?

Possible causes of P248B can include a faulty reductant heater 1, damaged wiring or connectors in the reductant heater circuit, a defective powertrain control module (PCM), or a malfunctioning temperature sensor.

3. How can I diagnose OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage)?

Diagnosing P248B typically involves using a scan tool to retrieve the fault code, checking the reductant heater 1 and its circuit for any visible damage, testing the temperature sensor, and inspecting the wiring and connectors for any issues.

4. Can I drive my vehicle with OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage)?

It is not recommended to drive your vehicle with an active P248B fault code, as it can lead to reduced engine performance and potential damage to the emissions system. It is best to address the issue promptly.

5. How can I repair OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage)?

Repairing P248B may involve replacing the faulty reductant heater 1, repairing or replacing damaged wiring or connectors, resetting the fault code with a scan tool, and ensuring proper operation of the temperature sensor.

6. Is OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage) a serious issue?

While P248B may not always cause immediate drivability issues, it is important to address this code promptly to prevent potential damage to the vehicle's emissions system and ensure optimal engine performance.

7. Can a DIY enthusiast fix OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage)?

Depending on your level of automotive repair experience, you may be able to address P248B yourself by following diagnostic procedures, replacing components as needed, and clearing the fault code using a scan tool.

8. How much does it cost to repair OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage)?

The cost of repairing P248B can vary depending on the specific cause of the issue, the cost of replacement parts, and labor rates. It is advisable to consult with a mechanic or repair shop for an accurate estimate.

9. Will OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage) cause a vehicle to fail emissions testing?

Yes, an active P248B fault code can cause a vehicle to fail emissions testing, as it indicates a malfunction in the reductant heater circuit, which is essential for reducing harmful emissions.

10. How can I prevent OBDII code P248B (Reductant Heater 1 Feedback Circuit High Voltage) from occurring in the future?

To prevent P248B from occurring in the future, it is important to perform regular maintenance on your vehicle, address any related fault codes promptly, and ensure proper operation of the emissions system components.