Introduction
If you own a Ford diesel vehicle equipped with a Selective Catalytic Reduction (SCR) emission system, you understand how critical the nitrogen oxide (NOx) sensor is to your vehicle’s performance and compliance. The WJIECO GK21-5E145-AF NOx Sensor (OEM cross-reference: 0281009331) is engineered as a direct-fit replacement for Ford’s original equipment, delivering factory-level accuracy at a fraction of the dealer cost.
Designed specifically for Ford’s 2.0L EcoBlue diesel engines found in Transit MK8 and Tourneo Custom models (2018–2024), this sensor ensures your SCR system operates at peak efficiency, helping you meet stringent Euro 6 emission standards while maintaining optimal fuel economy and engine performance.
Product Specifications
表格
| Specification | Details |
|---|---|
| Part Number | GK21-5E145-AF |
| OEM Cross-Reference | 0281009331, 2665334 |
| Brand | WJIECO |
| Sensor Type | Nitrogen Oxide (NOx) Sensor |
| Communication Protocol | CAN-Bus |
| Operating Temperature | -40°C to +850°C |
| Response Time | < 100ms |
| Mounting Position | Upstream / Downstream of SCR Catalyst |
| Certification | IATF 16949 |
| Warranty | 12 Months |
Compatible Vehicles
The WJIECO GK21-5E145-AF NOx sensor is a direct plug-and-play replacement for the following Ford diesel vehicles equipped with the 2.0L EcoBlue engine and SCR emission system:
- Ford Transit MK8 (2018–2024) – 2.0 EcoBlue Diesel
- Ford Tourneo Custom V362 (2018–2024) – 2.0 EcoBlue Diesel
- Ford Transit Custom V362 (2018–2024) – 2.0 EcoBlue Diesel
Note: Always verify your original part number matches GK21-5E145-AF or 0281009331 before purchasing to ensure compatibility.
How a NOx Sensor Works in Your Ford’s SCR System
Your Ford’s SCR (Selective Catalytic Reduction) system relies on precise NOx measurement to control Diesel Exhaust Fluid (DEF/AdBlue) injection. Here’s the process:
1. Dual-Sensor Configuration
Modern Ford diesel vehicles use two NOx sensors per exhaust bank:
- Upstream Sensor (Inlet): Measures NOx concentration before the SCR catalyst
- Downstream Sensor (Outlet): Measures NOx concentration after the SCR catalyst
2. Closed-Loop DEF Dosing
The Engine Control Unit (ECU) compares readings from both sensors to:
- Calculate the exact amount of DEF to inject into the exhaust stream
- Ensure >90% NOx conversion efficiency
- Prevent ammonia slip (unreacted DEF passing through the system)
3. Emission Compliance
By continuously monitoring NOx levels, the sensor ensures your vehicle meets Euro 6 emission regulations, reducing harmful nitrogen oxide emissions by up to 95% compared to older diesel technology.
Common Symptoms of a Failing NOx Sensor
A malfunctioning NOx sensor can trigger a cascade of issues in your Ford diesel. Watch for these warning signs:
🚨 Check Engine Light (CEL) Illuminates
Common diagnostic trouble codes (DTCs) associated with NOx sensor failure:
- P2200 – NOx Sensor Circuit Bank 1 Sensor 1
- P2201 – NOx Sensor Circuit Range/Performance Bank 1 Sensor 1
- P2202 – NOx Sensor Circuit Low Bank 1 Sensor 1
- P229F – NOx Sensor 2 Circuit Low Bank 1
- P22FB – NOx Sensor Plausibility Error
⚠️ Limp-Home Mode / Engine Derate
When the ECU detects unreliable NOx readings, it may enter a protective limp-home mode, limiting engine power and torque to prevent damage to the SCR catalyst and DPF system.
💧 Excessive DEF Consumption
A faulty upstream sensor can cause the ECU to overestimate NOx levels, leading to increased DEF consumption and more frequent AdBlue top-ups.
📉 Reduced Fuel Economy
Incorrect NOx readings disrupt the engine’s fuel injection mapping logic, resulting in suboptimal combustion and worse fuel efficiency.
🚫 Failed Emissions Test
A malfunctioning NOx sensor will almost certainly cause your vehicle to fail its MOT or emissions inspection, as the SCR system cannot operate correctly without accurate feedback.
Why Choose WJIECO GK21-5E145-AF NOx Sensor?
🏭 OEM-Grade Manufacturing
WJIECO is an IATF 16949 certified manufacturer with extensive experience supplying automotive sensors to major OEMs including GM, Renault, and SAIC Motor. Our sensors are built to the same stringent standards as original equipment.
🎯 Precision Engineering
- Fast response time (<100ms) ensures real-time feedback to the ECU
- Wide operating temperature range (-40°C to +850°C) handles extreme exhaust conditions
- High accuracy (±10 ppm drift over service life) meets Euro 6d-TEMP requirements
💰 Cost-Effective Solution
Save up to 60% compared to Ford dealer pricing without compromising on quality or performance. The WJIECO GK21-5E145-AF is engineered as a direct replacement – no modifications required.
🔌 Plug-and-Play Installation
- Exact match for original connector pinout
- Same mounting dimensions and thread size as OEM
- Pre-calibrated – no additional programming needed for most applications
🛡️ Durability & Reliability
- Vibration-resistant design withstands harsh under-vehicle conditions
- Corrosion-resistant housing for long service life
- 12-month warranty for peace of mind
Installation Tips for Ford GK21-5E145-AF NOx Sensor
Before You Start
- Ensure the exhaust system is completely cool to avoid burns
- Disconnect the negative battery terminal
- Locate the faulty sensor (upstream or downstream of SCR catalyst)
Step-by-Step Installation
- Disconnect the electrical connector – Press the release tab and pull gently
- Remove the old sensor – Use a 22mm NOx sensor socket or wrench. Apply penetrating oil if seized
- Inspect the mounting threads – Clean any corrosion or debris from the exhaust bung
- Install the new WJIECO sensor – Hand-tighten first, then torque to 40-50 Nm (29-37 lb-ft)
- Reconnect the electrical connector – Ensure it clicks into place
- Reconnect the battery
- Clear fault codes – Use an OBD-II scanner to reset the ECU and clear stored DTCs
Pro Tips
- Do not over-tighten – Excessive torque can damage the sensor or exhaust bung
- Avoid touching the sensing element – Oil or grease from your fingers can cause premature failure
- Check for exhaust leaks after installation by listening for hissing sounds
- Test drive the vehicle to ensure the check engine light stays off
Frequently Asked Questions
Q: How long does a NOx sensor typically last?
A: Under normal operating conditions, a quality NOx sensor like the WJIECO GK21-5E145-AF can last 80,000–120,000 km (50,000–75,000 miles). However, exposure to fuel or oil contamination, excessive soot, or coolant leaks can shorten its lifespan.
Q: Can I drive with a bad NOx sensor?
A: While your vehicle may still run, driving with a failed NOx sensor is not recommended. It can lead to increased DEF consumption, reduced fuel economy, potential SCR catalyst damage, and may trigger limp-home mode. Most importantly, your vehicle will not meet emission standards.
Q: Do I need to reprogram the ECU after replacement?
A: In most cases, no additional programming is required for the WJIECO GK21-5E145-AF. Simply clear the fault codes with an OBD-II scanner, and the ECU will automatically recognize the new sensor. Some Ford models may require a short drive cycle for full adaptation.
Q: How do I know if I need the upstream or downstream sensor?
A: The GK21-5E145-AF can be used for both positions on Ford 2.0 EcoBlue engines. Check your diagnostic trouble code:
- Sensor 1 = Upstream (before SCR catalyst)
- Sensor 2 = Downstream (after SCR catalyst)
Q: Is the WJIECO sensor covered by warranty?
A: Yes, all WJIECO NOx sensors come with a 12-month manufacturer warranty against defects in materials and workmanship.
Conclusion
The WJIECO GK21-5E145-AF Nitrogen Oxide Sensor (cross-reference: 0281009331) is the smart choice for Ford Transit MK8 and Tourneo Custom owners needing a reliable, cost-effective replacement for their SCR system. With IATF 16949 certification, OEM-grade precision, and a track record of supplying major automotive manufacturers, WJIECO delivers professional-grade quality you can trust.
Don’t let a failing NOx sensor leave you stranded with a check engine light, reduced power, or a failed emissions test. Upgrade to WJIECO today and restore your Ford diesel’s SCR system to peak performance.
Ready to replace your faulty NOx sensor? Shop the WJIECO GK21-5E145-AF now and enjoy fast shipping, competitive pricing, and expert technical support.
