Buy 456-0728 - DEF Manifold-Wisent Back Side - wisentpartscenter.com

Description

Genuine Cat 456-0728 DEF module manifold, also known as the DEF header or head unit. It mounts on top of the DEF tank and is what draws fluid out and sends it toward the SCR system. Everything is built into one assembly, the level float, the temp and quality sensors, the coolant heater and the filter on the suction side. Uses a 3 pin connector and is top mounted, so check your old unit before ordering since other numbers in this family use a different plug. Runs on Cat C series engines. Match by machine serial number and the number on the manifold you are replacing, these are built for specific tank setups and the wrong one will not read right.

Purpose of the Part

This is what gets the DEF out of the tank and over to the SCR system in the right amount for how much exhaust the engine is putting out, so the reaction in the catalyst happens the way its supposed to. It handles a few things at the same time. The pickup pulls fluid up from the bottom of the tank, the float rides on the center pin and tells the ECM how much is left, the sensor on top reads the urea to water mix to make sure the fluid is still good, and the coolant heater thaws it out when its cold so the system can still dose. The ECM works off all three readings, so if any one of them is wrong the machine will start cutting power even if nothing else is wrong with it.

Issue Symptoms / When to Replace

Usually the first thing you see is a DEF or SCR light and a derate while the fluid in the tank is perfectly good. If the float sticks or the level sensor goes bad the gauge reads wrong, so you get low DEF warnings on a full tank or the gauge just sits in one spot. If the quality sensor goes it flags good fluid as bad and starts the countdown to derate. These headers usually fail at the quality sensor first because ammonia works its way up into the top of the unit and eats the board. Before you replace anything check for debris or crystallized urea in the tank, air bubbles sitting on the sensor and a loose or corroded plug, all of that throws the same codes.

Signs to look for are DEF and SCR fault lights, derate stepping down to limp mode, a gauge that reads wrong or does not move, low DEF quality messages, flat acceleration, less pull on hills and a lower top speed.

Related codes may include:

- P2033 DEF level sensor
- P207F DEF quality
- P20EE SCR NOx catalyst efficiency
- plus machine specific J1939 and CDL codes for DEF level, temp and quality

Brand Information

Caterpillar has been building heavy equipment for over 95 years and their parts catalog is one of the biggest out there at more than 1.4 million numbers. On a DEF header that matters more than most parts because the ECM is making every dosing and derate decision off what this one unit reports. CAT builds it to match their own emissions calibration and their own tank setup, so the readings line up with what the machine expects. Aftermarket units can bolt in and still have the machine derating because the sensors are not reading the same.

Installation Notes

1. Clear up any engine, EGR, DPF or DOC faults first, SCR codes are usually coming from something upstream.
2. Pump the tank down below the manifold or drain it before you pull the old one.
3. Look in the tank while its open, if there is sediment or crystal buildup flush it out, that is what takes these units out.
4. Pull the suction filter and replace it if its plugged.
5. New seal on the flange, snug it evenly and dont crank on it.
6. Coolant lines back on, plug pushed all the way in until it locks.
7. Clear codes, let it cycle, then check that level, temp and quality are all reporting before it goes back to work.

How to Identify an OEM Part

Check the part number on the top of the unit where the connectors are and make sure it matches what you ordered. Also look at the header itself and make sure it looks like an OEM unit. A lot of aftermarket manufacturers change the way the header is built so the shape, the sensor box on top and the overall layout end up looking different from the original.

Why Buy 456-0728 from Wisent Parts

  • ⏱️
    Fast shipping
    Orders before 12PM EST ship same business day.
  • 🛡️
    180-day warranty
    All parts covered from delivery date.
  • ↩️
    Easy returns
    30-day returns.
  • ✅
    Verify fitment
    Send VIN/ESN and we’ll confirm.

Shop with confidence

Warranty & Return Information
Warranty Information

Wisent Parts offers a 180-day warranty on all parts from the date of delivery. This warranty covers orders placed directly through our website. If a part fails during this period, we’re here to help - whether it’s a replacement, repair, or refund. For full details, refer to the Warranty page.

Return Information

Wisent Parts accepts returns within 30 days of delivery. All returns are subject to a restocking fee. To qualify, parts must be unused and in their original condition. For full return instructions and restocking fee details, please refer to the Returns page.