AutoCodes – Audi – P203D Audi

P203D Audi Code - Reductant Level Sensor Circuit High

Quick Answer

The Diesel Exhaust Fluid (DEF) system is commonly called a Selective Catalytic Reduction (SCR) system to reduce harmful Oxides of Nitrogen (NOx). Common causes include Faulty Reductant Level Sensor, Reductant Level Sensor harness is open or shorted, Reductant Level Sensor 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: P203D Audi indicates Reductant Level Sensor Circuit High.
Common causes: Common causes include Faulty Reductant Level Sensor, Reductant Level Sensor harness is open or shorted, Reductant Level Sensor 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 2,532

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 Jan 02, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P203D Audi Description

The Diesel Exhaust Fluid (DEF) system is commonly called a Selective Catalytic Reduction (SCR) system to reduce harmful Oxides of Nitrogen (NOx). The diesel exhaust fluid is a Urea based solution of approximately 32% Urea and 64% distilled water. The solution is injected into the exhaust gas stream upstream of the SCR catalyst. Once in the exhaust system it decomposes and becomes Ammonia (NH3) and Carbon Dioxide (CO2). Within the catalyst, the NH3 and CO2 react with the Nox to create Oxygen (O2) and harmless Nitrogen (N2).
The system requires a storage tank for the diesel exhaust fluid, a pump with an integrated level sensor, pressure sensor, and fluid quality sensor, an injector fitted to the exhaust system, a fluid heater, and the catalyst.
The system is closely monitored for correct operation as a failure of the system will have a large impact on vehicle exhaust gas emissions of oxides of Nitrogen.

OBDII Code P203D Audi - Reductant Level Sensor Circuit High - AutoCodes.com — P203D Audi Code - Reductant Level Sensor Circuit High

What does this mean?

What are the Possible Causes of the DTC P203D Audi?

Faulty Reductant Level Sensor
Reductant Level Sensor harness is open or shorted
Reductant Level Sensor circuit poor electrical connection

How to Fix the DTC P203D Audi?

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 P203D Audi 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 P203D Audi code?

Need more information on how to fix the P203D Audi code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P203D Audi code diagnosed by a professional: Find a repair shop in your area

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 P203D Audi Code

1. What does the OBDII code P203D mean in an Audi?

P203D indicates a "Reductant Level Sensor Circuit High," meaning the vehicle's computer has detected an issue with the electrical circuit related to the reductant (DEF) level sensor.

2. What are the common symptoms of the P203D code in an Audi?

Common symptoms include a check engine light, a DEF warning light, incorrect DEF level readings, or the vehicle entering limp mode to prevent emissions violations.

3. What causes the P203D code to appear in an Audi?

Possible causes include a faulty DEF level sensor, damaged wiring or connectors in the sensor circuit, a malfunctioning DEF tank, or software glitches in the engine control module (ECM).

4. Can a bad DEF pump trigger the P203D code?

While the P203D code specifically relates to the DEF level sensor circuit, issues with the DEF pump or system can sometimes cause related errors.

5. How do I diagnose the P203D code in an Audi?

Start by inspecting the wiring and connectors around the DEF tank for damage or corrosion. Use a scan tool to monitor DEF sensor readings and check for related codes. Perform a continuity test on the sensor circuit if needed.

6. Can I still drive my Audi with the P203D code?

Driving with the P203D code is possible, but not recommended. The vehicle may enter limp mode or fail emissions tests, and prolonged issues with the DEF system could cause additional damage.

7. How is the P203D code fixed in an Audi?

Repairs may include replacing the faulty DEF level sensor, repairing or replacing damaged wiring or connectors, cleaning corroded terminals, or reprogramming the ECM if needed.

8. How much does it cost to fix the P203D code in an Audi?

Repair costs vary depending on the issue. Replacing a DEF level sensor typically costs $200â€“$600, while wiring repairs may cost less. Diagnostic fees are usually extra.

9. Can a software update resolve the P203D code in an Audi?

Yes, in some cases, an ECM software update may address false P203D triggers. Check with your Audi dealership for applicable updates or technical service bulletins (TSBs).

10. What happens if I ignore the P203D code in my Audi?

Ignoring the code can lead to reduced engine performance, failure to meet emissions standards, and potential damage to the DEF system, which could result in more costly repairs.