What is a NOx sensor (Nitrogen Oxide)?

Helps measure exhaust and oxygen mixture to determine how much AdBlue is injected into the diesel exhaust system in order to reduce emissions.

Where are they located?

There are two NOx sensors. The upstream is located after the turbo, the second is located in the catalytic converter.

Common problems:

the vehicle can have multiple faults on the dashboard which will put your car into limp mode. NOx sensors are directly linked to the emission system. faults include increased fuel consumption, unstable and erratic idle.

How to fix?

Topway Auto

Now Services SPRINTER utility and passenger vans!

DIESEL PARTICULATE FILTER

IN------TEM – PRE- PRE – TEMP----OUT

FILL LEVEL OF THE DIESEL PARTICAL FILTER

Depending on driving style, regeneration takes places every 300 to 500 miles, when the DPF is filled with soot to a level of about 45-50% of its capacity.

This corrects every 300 miles or less without you knowing it.

getting confused ??

why does it say the fill level is high yet the soot level is only 2g? My soot level was 2g and had dropped to 1g, however over a 40mile drove the fill levely went for 30 upto 45%?

What do you do if your particulate filter light comes on?

What do you do when you see the DPF light?

When the DPF light has become illuminated, it's telling you that 'passive regeneration' has failed and that you need to actively regenerate the diesel particulate filter. You can do this by increasing your speed to more than 40mph for between 10 and 15 minutes.

What does diesel particulate filter Full mean?

Diesel Particulate Filter Warning Light

The diesel particulate filter light turns on when the soot level from the diesel exhaust is high and your car is at risk of going into limp mode. by Spencer Cates on.

How do you manually regenerate a DPF?

To kick off a manual DPF regeneration you should

Put the vehicle in neutral.
Put on the hand brake.
Leave the pedals alone!
Press and hold the DPF button for 2 seconds or longer.

Common Symptoms

Symptoms for this code depend on the failure mode. As with other error codes, it activates the Check Engine light and registers the code to vehicle’s system. In many cases, there may not be any observable symptoms other than the Check Engine lights, but for some vehicles, the PCM may put the vehicle on ‘Limp Mode,’ which restricts both the performance of the engine and the transmission. Other vehicles with overcharged DPG may show other symptoms like:

Hard starting
Poor acceleration
Poor fuel economy

Concurrent trouble codes may also appear, such as problems referring to the EGR (exhaust gas recirculation) fuel trim faults, and turbocharger faults, even if there are no faults in these systems.

Possible Causes

Many possible causes lead to this error code, which mostly depends on the year and make of the vehicle. Here are common possible causes:

Driving habits – stop-and-go traffic and short trips overload the DPF, while the vehicle never gets hot enough to conduct a DPF regen cycle.

Overcharged DPF – usually happens in poorly-maintained engines or diesel fuel with high sulfur content. Some biodiesel fuels contain more than the normal level of soot, which can be excessive for the vehicle, and DPF regen cycle may not solve the problem, as it requires replacement.

Defective DPS – some factory-installed DPS are actually of poor quality, causing manufacturers to release updated and better quality parts.

Reflash – this is a software problem. Check with your dealership service center if they have addressed the software update for this error code for your vehicle.

Other possible causes include:

Defective particulate filter
Defective exhaust back pressure sensor
Exhaust leak
Poor quality of diesel fuel

How to Check

To diagnose this code, conduct a visual inspection of both the particulate filter, the back pressure sensor and associated wirings.

After checking those components, take the vehicle for a test drive with an OBD-II scanner connected to track the back pressure sensor readings. It would be best to have your mechanic with you for these diagnosis steps.

If Bank 1 seems to be sending mixed signals than the Bank 2, then your mechanic will conduct further troubleshooting of the sensor to determine whether the particulate sensor must be replaced.

How to Fix

The most common solution for this code is to manually put the vehicle on the DPF regen mode by using a scan tool or taking the vehicle out on the highway for a little longer to let the heat burn off the stored PM emissions.

Other potential methods to try:

Clearing the diesel particulate filter

Changing the diesel fuel

Replacing the particulate filter

EXHAUST BACK PRESSURE SENSOR

This is the sensor at the back of the turbo sitting between the turbo and EGR.

SYMPTOMS

Car starts in the morning, stays at lower than idle, revs, cuts out acceleration and cuts the engine.
- After a dozen or more starts I may be able to rev the engine and drive
- While driving the car will buck for a while
- All this with no CEL

Unplug the sensor; if the car seems normal, starts without an issue and does not buck so have been driving with it unplugged and now have a CEL.

A lot of people are changing Turbos thinking that they’re faulty when they should be changing this sensor first.

PROBLEM FIX

Tried to start the engine again this morning with the same result, it runs for 5 seconds and then stops, and then the CEL came up. (Code 0472).
Changed the sensor with a new one and cleared the code, now the engine start and runs like it should.

WHAT IF THE PROBLEM LOOKS LIKE THIS

2089-001 and 2089-002 error codes
At idle (700 rpm), the exhaust back pressure is 1967 mbar
at 2655 rpm, the exhaust back pressure is 2333 mbar
B28/8 (Pressure differential sensor (DPF)) at idle = 20.0 hPa
B19/9 (Temperature sensor upstream of DPF at idle = 496.04 (Fahrenheit)

interesting readings before and after:

B28/8 (Pressure differential sensor DPF) 20.0 hPa --> 4.0 hPa
Exhaust back pressure @idle 1967 mbar --> 1266 mbar

The old sensor was reading 4980 mbar. This is with the sensor out of the car.

The back pressure sensor ruptures, or some other type of failure occurs which makes the sensor read erroneously high. This puts the car into limp mode to protect it, as it’s detecting a high back pressure situation. Once the car warms up, the higher temperature affects the sensor to push the reading down, which explains why a restart will cancel limp mode.

CASE STUDY

engine speed 699 rpm (idle)
intake air pressure 977 mbar
boost pressure 758 mbar
exhaust back pressure 1086 mbar
charge pressure positioner 87.15 %
Ash content of DPF .62 g
DPF differential pressure 9 mbar. ( is this normal range?) maybe dpf needs to be replaced
b19 twc 378.06 celsius
b19/9 166.56 celsius

The last time I had it running I was being real rough on the peddle and it was running really good until I all of the sudden had the symptoms I describe above (hearing the air screaming out the turbo). Upon inspection I noticed the temperature sensor upstream of the DPF had popped out (B19/9). I think I only hand tightened it and forgot to torque it with a wrench. It seems to be giving good temperature readings so I don't think that is my problem. Anyways going to start with DPF DPS replacement now to see how it goes

Exhaust pressure is now 959 mbar while the engine isn’t running. Atmospheric pressure was 966 mbar here so about the same.

However, most of the exhaust gas pressure drop over a DPF tends to be caused by the accumulated soot, rather than the filter substrate. Problems arise if regeneration of the DPF does not occur on a regular basis, causing its pressure to drop to unacceptable levels.

Increased exhaust pressure can have a number of effects on the diesel engine, as follows:

Increased pumping work
Reduced intake manifold boost pressure
Cylinder scavenging and combustion effects
Turbocharger problems

DIFFERENTIAL PRESSURE SENSOR

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The DPF differential pressure sensor detects the difference between the exhaust pressure upstream and downstream of the Diesel Particulate Filter by means of the exhaust pressure sampling pipes upstream and downstream of the DPF

Diesel exhaust particulate filters (DPFs) are used in all light-duty diesel vehicles since 2007, to meet exhaust emissions standards. The heated exhaust gas from the DOC flows into the DPF, which captures diesel exhaust gas particulates (soot) to prevent them from being released into the atmosphere. This is done by forcing the exhaust through a porous cell containing a silicon carbide substrate with honeycomb-cell-type channels that traps the soot.

The main difference between the DPF and a typical catalyst filter is that the entrance to every other cell channel in the DPF substrate is blocked at one end. So instead of flowing directly through the channels, the exhaust gas is forced through the porous walls of the blocked channels and exits through the adjacent open-ended channels. This type of filter is also referred to as a “wall-flow” filter.

Diesel Oxidation Catalyst and Diesel Exhaust Particulate Filters Handle Diesel Exhaust

Operation

Soot particulates in the gas remains trapped on the DPF channel walls where, over time, the trapped particulate matter will begin to clog the filter. The filter must therefore be purged periodically to remove accumulated soot particles. The process of purging soot from the DPF is described as regeneration. When the temperature of the exhaust gas is increased, the heat incinerates the soot particles trapped in the filter and is effectively renewed.

EGT 1 and EGT2 are used by the PCM to help control after treatment

The following two exhaust gas temperature sensors are used to help the PCM control the DPF.

EGT sensor 1 is positioned between the DOC and the DPF where it can measure the temperature of the exhaust gas entering the DPF.
EGT sensor 2 measures the temperature of the exhaust gas stream immediately after it exits the DPF.

The powertrain control module monitors the signals from the EGT sensors as part of its calibrations to control DPF regeneration. Proper exhaust gas temperatures at the inlet of the DPF are crucial for proper operation and for starting the regeneration process. Too high a temperature at the DPF will cause the DPF substrate to melt or crack. Regeneration will be terminated at temperatures above 1,470°F (800°C). If the temperature is too low, self-regeneration will not fully complete the soot-burning process.

The DPF differential pressure sensor (DPS) has two pressure sample lines.

One line is attached before the DPF.
The other is located after the DPF.

The exact location of the DPS varies by vehicle model type such as medium duty, pickup, or van. By measuring the exhaust supply (upstream) pressure from the DOC, and the post DPF (downstream) pressure, the PCM can determine differential pressure, also called “delta” pressure, across the DPF. Data from the DPF differential pressure sensor is used by the PCM to calibrate for controlling DPF exhaust system operation.

The primary reason for soot removal is to prevent the buildup of exhaust back pressure. Excessive back pressure increases fuel consumption, reduces power output and potentially causes engine damage. Several factors can trigger the diesel PCM to perform regeneration, including:

Distance since last DPF regeneration
Fuel used since last DPF regeneration
Engine run time since last DPF regeneration
Exhaust differential pressure across the DPF

A number of engine components are required to function together for the regeneration process to be performed, as follows:

PCM controls that impact DPF regeneration include late post injections, engine speed, and adjusting fuel pressure.
Adding late post injection pulses provides the engine with additional fuel to be oxidized in the DOC, which increases exhaust temperatures entering the DPF to 900°F (500°C) or higher.
The intake air valve acts as a restrictor that reduces air entry to the engine, which increases engine operating temperature.
The intake air heater may also be activated to warm intake air during regeneration.

Regeneration burns the soot and renews the Diesel Exhaust Particulate Filter

DPF regeneration can be initiated in a number of ways, depending on the vehicle application and operating circumstances. The two main regeneration types are as follows:

Passive regeneration. During normal vehicle operation when driving conditions produce sufficient load and exhaust temperatures, passive DPF regeneration may occur. This passive regeneration occurs without input from the PCM or the driver. A passive regeneration may typically occur while the vehicle is being driven at highway speed or towing a trailer.
Active regeneration. Active regeneration is commanded by the PCM when it determines that the DPF requires it to remove excess soot buildup and conditions for filter regeneration have been met. Active regeneration is usually not noticeable to the driver. The vehicle needs to be driven at speeds above 30 mph for approximately 20 to 30 minutes to complete a full regeneration. During regeneration, the exhaust gases reach temperatures above 1,000°F (550°C). Active regeneration is usually not noticeable to the driver.

Assuming a 6 g/L maximum soot load limit

After only 33,000 miles (53,000 km) of on-road use, approximately 50% of the material accumulated in the DPF is ash. In other words, the amount of ash equals the amount of soot at the maximum allowable soot load limit of 6 g/L. Further, after 150,000 miles (241,000 km) of operation—equivalent to the minimum EPA ash cleaning interval—ash comprises over 80% of the material trapped in the DPF, with the minority being soot.

Regeneration will not burn off ash. Only the particulate matter (PM) is burned off during regeneration. Ash is a noncombustible by-product from normal oil consumption. Ash accumulation in the DPF will eventually cause a restriction in the particulate filter. To service an ash-loaded DPF, the DPF will need to be removed from the vehicle and cleaned or replaced. Low ash content engine oil (API CJ-4) is required for vehicles with the DPF system. The CJ-4 rated oil is limited to 1% ash content.

Now that you’re familiar with Exhaust Gas Filtration, Regeneration, and Conversion, try out our free Automotive Service Excellence Tests to see how much you know!

Understanding the Differences Between Ash and Soot

Soot particles form in the engine’s combustion chamber as the result of incomplete combustion. The particles glow and agglomerate in the exhaust system before reaching the DPF, where the particles are captured in the filter and oxidized during the regeneration process. Ash, which is the incombustible material left behind following the regeneration process builds up over long periods of time. In conventional diesel engines, only a small percentage of the soot is composed of ash, typically less than 5% [1].

Figure 1 provides a comparison of the soot and ash particle diameters to the diameter of a small grain of beach sand and the diameter of a human hair. As shown in the figure, soot agglomerates are quite small, with average diameters of only 100 nm (0.1 microns). Ash particles, on the other hand, start out in the engine as particles even smaller than soot, but grow and agglomerate over time in the DPF (1 – 10 microns), which exceeds the size of the soot particles that originally carried the ash into the filter to begin with [2].

Ash is, therefore, formed in the DPF over long periods of time, following repeated regeneration events and builds up in the DPF until it is removed through filter cleaning. The specific ash properties, and the ease with which the ash may be removed from the DPF are strongly affected by a large number of factors occurring over the entire operating history of the filter. In contrast, soot remains in the DPF for only a short period of time before it is regenerated.

Figure 2: Soot and ash removed from a Diesel Particulate Filter (DPF).

Although the ash only makes up a very small fraction of the incoming soot, it remains in the DPF indefinitely and builds up to high levels. In fact, after only 33,000 miles, the amount of ash in the DPF may equal the amount of soot (prior to regeneration), and after 150,000 miles, nearly 80% of the material trapped in the DPF is ash. In other words, a high mileage DPF contains much more ash than the soot it was originally designed to capture [3].

Figure 2 shows a comparison between soot (left vial) and ash (right vial) removed from two different DPFs at CTS. The soot is composed primarily of carbon, but also contains other hydrocarbons originating in the fuel and engine oil, as well as sulfates, and a small amount of ash. The specific proportion of the various soot constituents is dependent upon the engine operating conditions, as well as the type of fuel and oil used. Soot is easily distinguished from the residual ash by its dark color. The ash, in comparison, is much lighter in color and is composed of primarily metallic components which are incombustible. Although many sources contribute to ash, the majority of the ash originates in the engine oil.

Ash properties can also vary greatly between DPFs used on different vehicles or pieces of equipment, based on differences in the engine operating conditions, lubricating oil, regeneration strategy, and type of DPF. These differences in ash properties also play an important role in how the ash affects engine and DPF performance and also how easily the ash can be removed from the DPF.

P246B

P246B - Vehicle Conditions Incorrect for Particulate Filter Regeneration

Description :

This fault code is stored when the vehicle conditions for particle filter regeneration are not met. The engine will have certain requirements prior to commencing regeneration such as the drivers door being closed, the engine being at operating temperature, the glow plugs being operational, etc.

Possible Causes :

Component

Fuel Pressure Regulator

Fuel Pump

Injector

Mechanical Defect

https://www.youtube.com/watch?v=GsVQQuIaVAY

DIFFERENTIAL SENSOR WIRE REPAIR

Design

The DPF pressure differential sensor consists of a piezo resistant pressure sensor element, electronics for signal amplification and temperature compensation. All components are integrated in a silicon chip. The silicon chip is protected from corrosion by a protective gel and is cast in a plastic housing.

Function

The DPF pressure differential sensor detects the difference in the exhaust pressure upstream and downstream of the DPF over the exhaust pressure connections upstream and downstream of the DPF over the pressure lines.

The pressure difference between the exhaust gas pressures upstream and downstream of DPF affects the piezo resistant pressure sensor element.

This generates a voltage, which is amplified by the integrated silicon chip and sent as a voltage signal to the CDI control unit.

2015 SPRINTER 3.0

IDLE----------- 0.2PSI

3000 RPM--.1.2 PSI

https://www.youtube.com/watch?v=XfK6RnrsXPo

MMS:

2011 Mercedes-Benz Sprinter 2500

Aug 26, 2020

Engine:

3.0L Eng

License:

VIN:

WDZPE7CC1B5583456

Odometer:

ENGINE POWER INSUFFICIENT, ENGINE DIAGNOSIS INDICATOR LAMP LIGHTS UP AND DIFFERENTIAL PRESSURE SENSOR FAULT CODES CURRENT AND/OR STORED IN CDI CONTROL UNIT

TECHNICAL SERVICE BULLETIN

Reference Number(s): LI07.04-N-056999 Version 7, Date of Issue: February 29, 2016

Sprinter:

OM642 in MODEL 906.### #S up to 772677; OM642 in MODEL 906.### #N up to 545455

Design Group:

07.04 Senders, sensors

Reason For Change:

Updated Remedy

COMPLAINT

Engine warning lamp in instrument cluster
Reduced engine power
Fault code current/stored in CDI control unit

CAUSE

Cause 1:

Iodomethane degassing from the pressure differential hoses (rubber) can be deposited on the differential pressure sensor. Lifting (arrow) of the chip in the differential pressure sensor from the circuit board caused by the degassing of iodomethane from the pressure differential hoses (see Figure 2).

Cause 2:

Contact fault in electrical connection of diesel particulate filter differential pressure sensor.

Cause 3:

Cooler of exhaust gas recirculation system blocked (see Figure 6).

ATTACHMENTS

File

Description

Figure 2

Chip lifting off circuit board

Figure 6

Cooler of exhaust gas recirculation system

REMEDY

Remedy for cause 1:

Safety notice: Risk of injury to skin and eyes when handling hot or glowing objects. Gloves, protective clothing and safety glasses must be worn when working in the vicinity of the exhaust system.

Replace differential pressure sensor (see: AR07.04-D-0006SD).
Replace all pressure differential hoses.

NOTE: The new hoses do not contain iodomethane.

NOTE: Disconnect pressure differential hoses from differential pressure sensor carefully to avoid damage.

In all cases the pressure differential hoses must be replaced and reordered! Do not use pressure differential hoses from old stocks!

Remedy for cause 2:

Remove air filter housing (see: AR09.10-D-1150SF).
Separate electrical connection (1) (see Figure 3).
Replace diesel particulate filter differential pressure sensor (B28/20) (see: AR07.04-D-0006SD).
Replace all pressure hoses with hose clamps between diesel particulate filter differential pressure sensor (B28/20) and diesel particulate filter (see: AR09.10-D-1150SF).
Cut off wiring harness (2) approx. 10 mm before electrical connection (1) (see Figure 3 at arrow).
Cut new lines (3), to length "a" (approx. 150 mm) from the electrical connection (9) (see Figure 3).

NOTE: Fabricating the new lines (3) in the workshop is not permissible, as this can lead to more contact faults.

Attach new lines (3) to wiring harness (2) with solder connector sleeves (5) (see Figure 3).

NOTE: Refer to the circuit diagram when connecting the new lines (3) (see Figures 4 and 5).

Special tools: Use special tools 220 589 01 99 40 (wire stripper), 220 589 04 99 00 (wiring harness repair kit supplement for passenger cars) and 129 589 01 98 00 (welding pearl catcher).

Commercially available tools: Hot air gun.

Insulate wiring harness (2) and new electrical lines (3) with fabric tape (see Figure 3).
Plug in new electrical connections (9) (see Figure 3).

NOTE: The electrical connection (9) must lock correctly.

Fasten new electrical wiring harness with cable tie (8) (see Figure 3).

NOTE: The cable tie (7) already on the electrical connection (9) must not be removed.

Install air filter housing (see: AR09.10-D-1150SF).

Remedy for cause 3:

Check cooler of exhaust gas recirculation system.

Condition: Only if fault code 170400 is still present.

NOTE: If the cooler of the exhaust gas recirculation system is blocked (see Figure 6), continue with step 2 below.

Replace the EGR cooler.

NOTE: Include a picture of the EGR cooler blockage at the time of replacement and return it along with the EGR cooler to the QEC.

ATTACHMENTS

File

Description

Figure 3

Remedy 2: Wiring harness extension for diesel particulate filter differential pressure sensor

Figure 4

Remedy 2: Wiring diagram

Figure 5

Remedy 2: Wiring diagram