Level Sensor 591-3427 535-6922 Fits for Caterpillar C4.4 C3.6 Engine D4 CS66B CS56B CS14 CS16 AP455 AP655
Level Sensor 591-3427 535-6922 Fits for Caterpillar C4.4 C3.6 Engine D4 CS66B CS56B CS14 CS16 AP455 AP655 is backordered and will ship as soon as it is back in stock.
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Powering 10,000+ Commercial Fleets
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One Year Warranty
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Easy 60-day Return
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Expert support & Fitment Guarantee
Compatibility Information
| Part Number | 591-3427, 535-6922 |
|---|---|
| Make | Fits Caterpillar |
| Model | 337, D4, CS74B, CS76B, 535, 120, C4 |
Description
Description
Level Sensor 591-3427 535-6922 – Replacement for Caterpillar C4.4 C3.6 Engine D4 CS66B CS56B CS14 CS16 AP455 AP655
Aftermarket diesel exhaust fluid (DEF) level sensor engineered for accurate fluid level monitoring and reliable emissions system performance in Caterpillar engine and equipment applications. Precision-manufactured components ensure drop-in compatibility with correct fitment.
Technical Specifications
- Part Numbers: 591-3427, 5913427, CA5913427, 535-6922, 5356922, CA5356922
- Tank Interface: 4
- Suction Fitting Diameter: 3/8 in
- Return Fitting Diameter: 5/16 in
- Coolant Inlet Fitting Diameter: 5/8 in
- Coolant Outlet Fitting Diameter: 5/8 in
- Header Height: 11.4 in
- Installation Depth: 337.41 mm (~13.28 in)
- Wire Length: 15.5 in
- Electrical Connector: Deutsch DT4 (STD), 4-pin
- Condition: New, aftermarket replacement
- Function: Monitors DEF tank fluid level and transmits data to the engine control module to maintain emissions compliance and prevent low-fluid shutdowns across Caterpillar Tier 4 engine and equipment applications
Equipment Compatibility
Note: Compatibility is provided for reference. Please verify against your part number before ordering.
Fits the Following Applications:
- Caterpillar Engine: C4.4, C3.6
- Caterpillar Tractor: D4
- Caterpillar Asphalt Paver: AP400, AP455, AP500, AP555, AP600, AP655, PE636
- Caterpillar Compactor: CP12, CP14, CP16, CP56B, CP68B, CP74B, CS12, CS13, CS14, CS16, CS17, CS19, CS56B, CS66B, CS68B, CS74B, CS76B, CS78B
- Caterpillar Motor Grader: 120 GC
Why Choose This Level Sensor
The DEF level sensor is a critical emissions system component in your Caterpillar Tier 4 engine — it continuously monitors fluid level in the DEF tank and feeds real-time data to the ECM to maintain SCR system operation and regulatory compliance. A failed or inaccurate level sensor triggers fault codes, activates warning indicators, and can result in derate conditions or equipment shutdown that halts production on active job sites. This replacement unit delivers:
- Accurate level monitoring – Engineered to meet the signal output, connector, and dimensional specifications of Caterpillar C4.4 and C3.6 DEF system requirements
- Exact-fit installation – Direct replacement with correct installation depth, fitting diameters, wire length, and Deutsch DT4 4-pin connector to match Caterpillar equipment specifications without modification
- Durable construction – Built to withstand continuous DEF exposure, thermal cycling, and the demanding duty requirements of Caterpillar paver, compactor, grader, and tractor applications
- Cost-effective solution – Aftermarket quality at a fraction of dealer pricing
Package Contents
- 1 × Level Sensor 591-3427
Essential for Caterpillar C4.4, C3.6 engine, D4 tractor, AP455, AP655 paver, CS66B, CS56B, CS14, CS16 compactor, and 120 GC motor grader DEF system maintenance and level sensor replacement. Keep your Caterpillar equipment delivering full emissions compliance and uninterrupted operation on every job.
1 Year Warranty
1 Year Warranty
Fab Heavy Parts is excited to offer a 12-month warranty on all new replacement/aftermarket parts starting from your original purchase date.
Enjoy peace of mind with Fab Heavy Parts!
For more warranty details, please check out our warranty policy.
Fast Delivery
Fast Delivery
Estimated delivery time 3-6 workdays
No Core Charge
No Core Charge
We don't have a core charge for any products.
Frequently Asked Questions
Do you ship to the UK?
Yes, we ship to mainland UK, Scotland, Wales, and Northern Ireland. Shipping rates and estimated delivery times are displayed at checkout.
Will I be charged import duties or VAT?
Our prices do not include VAT or import duties. UK and European customers are responsible for any applicable import taxes, VAT, and customs fees charged upon entry into their country. These charges vary depending on the commodity code, order value, and destination country. We recommend checking with your local customs authority or HMRC (for UK customers) before placing your order.
How long will delivery take to the UK?
Standard delivery to UK addresses is typically 4–7 business days from dispatch. Express options may be available at checkout. Customs clearance can add 1–3 additional business days in some cases.
Are your parts compatible with UK and European specifications?
Many of our engine, hydraulic, and powertrain components are compatible with EU and UK-market machines. Please verify the part number against your OEM manual or machine serial plate before ordering. Contact us with your machine make, model, and serial number if you need fitment confirmation.
What currency will I be charged in?
UK customers are billed in GBP (£).
What is your returns policy for UK orders?
We accept returns within 30 days of delivery for unused parts in original packaging. UK customers are protected under the Consumer Contracts Regulations 2013, which grants a 14-day right to cancel an order before it has been dispatched. Once an order has been fulfilled and shipped, standard return terms apply. Return shipping costs for non-defective items are the buyer's responsibility.
How do I verify a part number before ordering?
Each listing includes part numbers and compatible machine models. Cross-reference with your OEM workshop manual, or contact our technical team via the contact form with your machine make, model, year, and serial number.
Do you offer trade accounts for UK buyers?
Yes. UK trade customers can apply for a B2B account to access volume pricing and dedicated account support.
What payment methods do you accept?
We accept all major credit and debit cards including Visa, Mastercard, and American Express. We also support PayPal, Apple Pay, and Google Pay at checkout. For B2B and trade customers, bank transfer (BACS) and net payment terms may be available upon account approval — please contact us to discuss your requirements.
