AutoCodes – Generic – P20B5

P20B5 Code - Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Open

Quick Answer

The Diesel Exhaust Fluid (DEF) Supply Pump Assembly has an internal heater to prevent the fluid from freezing inside the pump. Common causes include Faulty Diesel Exhaust Fluid (DEF) Supply Pump Assembly, Diesel Exhaust Fluid Supply Pump Assembly harness is open or shorted, Diesel Exhaust Fluid Supply Pump Assembly 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: P20B5 indicates Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Open.
Common causes: Common causes include Faulty Diesel Exhaust Fluid (DEF) Supply Pump Assembly, Diesel Exhaust Fluid Supply Pump Assembly harness is open or shorted, Diesel Exhaust Fluid Supply Pump Assembly 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 8,825

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 15, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P20B5 Description

The Diesel Exhaust Fluid (DEF) Supply Pump Assembly has an internal heater to prevent the fluid from freezing inside the pump. The power supply and control circuits are controlled by the DEF Dosing Control Unit. The DEF Supply Pump Heater is integrated into the DEF Supply Pump Assembly and is not serviced separately. The DEF Dosing Control Unit will illuminate the MIL light via the Powertrain Control Module (PCM) immediately after the diagnostics runs and fails and the line heater will be disabled. The DEF Dosing Control Unit will turn off the MIL light via the PCM when the monitor runs and passes in three consecutive key cycles. The Diagnostic Trouble Code (DTC) will be set when the DEF Dosing Control Unit detects that the DEF Supply Pump heater circuit is open or shorted to ground.

OBDII Code P20B5 - Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Open - AutoCodes.com — P20B5 Code - Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Open

What does this mean?

What are the Possible Causes of the DTC P20B5?

Faulty Diesel Exhaust Fluid (DEF) Supply Pump Assembly
Diesel Exhaust Fluid Supply Pump Assembly harness is open or shorted
Diesel Exhaust Fluid Supply Pump Assembly circuit poor electrical connection
Faulty Diesel Exhaust Fluid Dosing Control Unit

How to Fix the DTC P20B5?

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 P20B5 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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Need Help with the Code?

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Information for Specific Makes

P20B5 Dodge — Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Open
P20B5 RAM — Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Open

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 P20B5 Code

What does the OBDII code P20B5 mean?

Code P20B5 indicates an issue with the Diesel Exhaust Fluid (DEF) reductant pump heater control circuit, typically an open circuit preventing proper operation of the heater.

What are the symptoms of code P20B5?

Common symptoms include the check engine light turning on, reduced engine performance, and possible DEF system-related warnings on the dashboard.

What causes code P20B5?

Typical causes include damaged wiring or connectors, a failed reductant pump heater, or issues with the control module.

Can I drive with a P20B5 code?

While the vehicle may still be drivable, ignoring the code could lead to reduced engine performance or issues with the DEF system affecting emissions compliance.

How is code P20B5 diagnosed?

Technicians diagnose this code by inspecting the wiring and connectors for damage, testing the reductant pump heater, and checking for proper operation of the control circuit.

How do you fix code P20B5?

Repairs may include replacing damaged wiring or connectors, installing a new reductant pump heater, or addressing issues with the control module.

How much does it cost to repair code P20B5?

The repair cost varies, but replacing a reductant pump heater may cost between $300 and $800, depending on labor rates and vehicle specifics.

Can a faulty reductant pump heater cause other issues?

Yes, a malfunctioning heater can prevent proper DEF operation, potentially leading to increased emissions or triggering other related fault codes.

Is code P20B5 specific to certain vehicles?

This code is more common in diesel vehicles equipped with DEF systems, such as trucks and SUVs, but it can appear on any vehicle utilizing similar technology.

How can I prevent code P20B5 from occurring?

Regular maintenance of the DEF system, inspecting wiring and connectors for damage, and addressing issues promptly can help prevent this code from appearing.