Service Exhaust Fluid System Message GM trucks? (Perfect answer)

  • Service Exhaust Fluid System is the only message. No DTC’s, no check engine light. Truck is in middle of a regen, which it started with only 10g of soot on the meter.

Why does my truck say service exhaust fluid system?

Service Exhaust Fluid System (Tamper) – Displays when a Diagnostic Trouble Code (DTC) sets related to the DEF system that is interpreted as tampering with the system. Exhaust Fluid Range X MI (KM) – Displays when the DEF tank has a range of 1,000 miles (1,609 km) or less remaining.

How do you clear a diesel exhaust fluid system?

If you spill a small amount of Diesel Exhaust Fluid (DEF), it can be washed away with water or wiped up. If you leave it to dry it will turn into white crystals. These can be washed away with water. If you spill a large amount of DEF then contact your DEF supplier for advice.

Why is my diesel exhaust fluid light on?

Generally, a warning light will come on when DEF needs to be added soon. If the light is ignored for too long, the vehicle will likely go into a reduced power mode. If the DEF level falls too low, the engine will not start until fluid is added.

What DEF fluid does GM recommend?

The Duramax line recommends using only ACDelco DEF for their engines. This GM DEF is specifically made for Duramax engines. The ACDelco DEF meets every stringent guideline for purity. DEF will need to be refilled approximately every 1000 miles of use.

What does exhaust system service required mean?

Exhaust Service Required — See Dealer Now. — This message indicates regeneration has. been disabled due to a system malfunction. At this point the engine Powertrain Control.

What does Exhaust Fluid Quality Poor mean?

The Exhaust Fluid Quality Poor DIC message notifies the customer that the ECM has detected a drop in the SCR NOx reduction efficiency. This PI is to assist with vehicles that have difficulty completing the DEF (diesel exhaust fluid) quality test and/or clearing the Exhaust Fluid Quality Poor Message.

How do you know if your DEF fluid is bad?

The easiest way to spot bad DEF is to look at it. The fluid is naturally clear so if it appears cloudy or colored, it’s likely contaminated or old. Contaminates, including small particles or larger rocks or dirt will also be easy to see. If DEF has gone bad, do not attempt to use it.

How do you reset service DEF System See dealer?

Apparently (no I have not had to try) you can disconnect the battery cables and touch them together for 20 seconds or so to drain all the electronics. Reattach and the count down should reset. MAKE SURE TO DISCONNECT BOTH BATTERIES BEFORE TOUCHING CABLES TOGETHER!!!!

How does diesel exhaust fluid system work?

Small quantities of diesel exhaust fluid (DEF) are injected into the exhaust upstream of a catalyst, where it vaporizes and decomposes to form ammonia and carbon dioxide. The ammonia (NH3) is the desired product which in conjunction to the SCR catalyst, converts the NOx to harmless nitrogen (N2) and water (H2O).

Can you drive a truck without DEF fluid?

SCR Systems Modern trucks will not run without the DEF. Hence the need for diesel truck owners to check their fluid levels frequently. Reducing emissions should be everyone’s goal. Maintaining your vehicle would also reduce emissions and DEF consumption.

Is it bad to drive without DEF?

Drivers need to be vigilant when it comes to DEF, so that they don’t lose time, damage their vehicles, and end up in big trouble with their employer. Ignoring the DEF light is never a good idea, so if it comes on, the driver should pull over and have their DEF refilled immediately.

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Can low DEF cause check engine light?

One of the most common reasons for seeing the check engine light on a diesel truck is the aftertreatment system. This means even something as small as your diesel exhaust fluids being low could trigger your check engine light.

Is the 2020 Duramax an L5P?

GM’s 6.6L L5P Duramax joined the ranks of Chevrolet Silverado HD and GMC Sierra HD trucks in 2017. 2020 Chevrolet Silverado 2500HD with the 6.6L L5P Duramax engine.

How much DEF fluid does a 2019 Duramax hold?

The DEF tank is approximately 5 gallons (18.9 liters). On pickup trucks, the DEF tank fill nozzle is located on the passenger side, under the hood and is sealed by a blue cap.

Does it matter what brand of DEF fluid I use?

DEF is just a fancy name for a mixture of water and a chemical called urea. There’s really no magic behind it, which means that any brand of diesel exhaust fluid is going to work just fine in your car.

Service Exhaust Fluid System Message GM trucks

In order to
resolve a Service Exhaust Fluid System Message and problem codes P203D, P21AB, or P21B0 on the trucks mentioned below, General Motors has published service bulletinsPIP4887A and12-06-04-002E. This advisory may apply to you if you observe the ‘Service Exhaust Fluid System’ and ‘See Owner’s Manual Now’ messages displayed on the instrument cluster and scan the vehicle and discover fault codes P203D, P21AB, and P21B0. P203B–Performance of the Reductant Level Sensor, The ECM gets a serial data message from the reductant sensor module informing it that the sensor signals for the reductant level are not credible.

In response to a serial data message from the reductant sensor module, the ECM determines that the voltage of the emission reduction fluid tank level sensor 1, 2, or 3 is less than 0.17 V for a period of more than 3 seconds.

P203D–High Voltage Reductant Level Sensor 1 Circuit (P203D).

An open circuit, or a voltage within this range, implies a short circuit.

A voltage inside this range implies that there is a short to the voltage source.

Circuit P21AA (Reductant Level Sensor 2) has a low voltage. In response to a serial data message from the reductant sensor module, the ECM determines that the voltage of the emission reduction fluid tank level sensor 1, 2, or 3 is less than 0.17 V for a period of more than 3 seconds. It is possible to have a short to ground with a voltage in this range. Circuit with high voltage for the Reductant Level Sensor 2 (P21AB). The ECM gets a serial data message from the reductant sensor module informing it that the voltage of the emission reduction fluid tank level sensor 1, 2, or 3 is between 3.56-4.74 V over a period of more than 3 seconds (3.56-4.74 V).

  1. In response to a serial data message from the reductant sensor module, the ECM determines that the voltage of the emission reduction fluid tank level sensor 1, 2, or 3 has been more than 4.74 V for a period of more than 3 seconds.
  2. P21AF – Low Voltage Reductant Level Sensor 3 Circuit (P21AF).
  3. It is possible to have a short to ground with a voltage in this range.
  4. The ECM gets a serial data message from the reductant sensor module informing it that the voltage of the emission reduction fluid tank level sensor 1, 2, or 3 is between 3.56-4.74 V over a period of more than 3 seconds (3.56-4.74 V).
  5. In response to a serial data message from the reductant sensor module, the ECM determines that the voltage of the emission reduction fluid tank level sensor 1, 2, or 3 has been more than 4.74 V for a period of more than 3 seconds.

Models Affected by PIP4887A

Chevrolet Express and Silverado models for 2010-2011 GMC Savana and Sierra (2010-2011) RPO codes LML or LGH are associated with the 6.6L Duramax Diesel Engine.

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What the Service Exhaust Fluid P203D P21AB or P21B0 means

The reductant tank has a level/temperature sensor that communicates with the ECM about the level and temperature of the reductant. Level and temperature sensors receive power from the underhood electrical center and are grounded by a chassis ground circuit, which is connected to the chassis ground circuit. There are three detecting components in the level sensor. Sensor 3 measures the maximum concentration of reducing agent, whereas sensor 2 measures the lowest concentration of reducing agent.

The location of Reductant Level Sensor 3 is less than half of the range of the DEF tank level sensor.

Diagnose Service Exhaust Fluid message

Using a digital meter, measure the resistance of the Reductant Tank Heater to ensure proper operation. heater for the reductant tank Disconnect the Glow Plug Control Module and measure the resistance on pin 11 (orange/white) and ground to ensure that it is within acceptable limits. You should be able to view 2-4. If the resistance of the tank heater is incorrect, the heater should be replaced. Following the replacement of the heater, a scan tool should be used to execute a reduction fluid tank level reset.

The system must be capable of holding 61-83 psi.

The year 2020 is a leap year.

Rick Muscoplat posted a blog entry on

Diesel Exhaust Fluid Basics

The Fundamentals of Diesel Exhaust Fluid Engines equipped with the Duramax diesel engine, which is available on GM full-size trucks and vans from 2011 to 2016, require the injection of Diesel Exhaust Fluid (DEF) as part of the exhaust after-treatment process, which decreases emissions. DEF is a colorless, transparent solution of water and nitrogen-based urea product that contains 32.5 percent urea by weight and is 32.5 percent urea by weight in total. It is a naturally occurring, biodegradable substance.

  • The Selective Catalyst Reduction (SCR) system, a DEF injection system, two NOx sensors and smart module assemblies, and other components of the Duramax diesel engine exhaust after-treatment system work together to decrease oxides of nitrogen (NOx).
  • It is referred to as selective because it employs ammonia as a reductant inside a catalyst system to lower NOx levels and hence improve air quality.
  • The urea is rapidly hydrolyzed, resulting in the production of oxidizing ammonia.
  • The DEF that has been injected mixes with the exhaust gas before it reaches the SCR system.
  • When the DEF level goes below a calibrated amount, a sequence of prompts and warnings are issued to ensure that the vehicle remains in compliance with emission rules.
  • When the anticipated distance goes below 1609.34 kilometres, DEF warnings are flashed on the Driver Information Center (DIC), which is standard practice.
  • The current DEF warning level for the car is shown on the scan tool as Reductant Level Warning Indicator Command Level 1 through Level 9 on the vehicle’s dashboard.

The DEF messages that appear on the DIC are dependent on the engine’s operating circumstances at the time of presentation.

When a DTC relating to the DEF system is set, it is treated as an Emission Control fault and the Service Emission System (Not-Tamper) indicator is shown.

Displays when the DEF tank has a remaining range of 1,000 miles (1,609 km) or less.

It is possible that the DEF miles countdown does not correspond to the actual distance traveled by the vehicle.

Every time the DIC is used, the correct sequence of repair will be displayed.

It will then display ‘Exhaust Fluid Quality Poor,’ which indicates that the exhaust fluid quality has to be improved.

The Diesel Airflow Leak Equivalency Ratio (DALER) and the Diagnostic Trouble Code P0101 Calibrations that are incorrect Leaks in the exhaust system The charge air cooler system has DEF contamination due to a leak.

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Downpipe 1: The sensor number for NOx.

3: Injector for hydrocarbons (HC).

Diesel Exhaust Fluid (DEF) Reductant Injector (number 25) SCR stands for Selective Catalyst Reduction (SCR) 6 is the sensor number for NOx emissions.

Status of the Frozen Tank During operation at temperatures of -9° C or below, the ‘Exhaust Fluid Range’ warning may appear on the digital instrument panel (DIC) even when the DEF fluid reservoir has been fully topped off.

DEF has the same properties as water and will freeze at -11° C.

This will cause the logic of the ECM to assume a default fluid level if it happens.

This is a feature of the system’s way of working.

The level sensor pins cannot be read unless the DEF has thawed sufficiently to allow them to be read by the refill detection system.

Because DEF operates in the same way as water, it will freeze and expand.

It is possible that adding more than the 20.0627 L useable capacity may prevent DEF growth while frozen.

When adding DEF to the tank, use the ACDelco DEF nozzle to make it easy to fill the tank with DEF.

It is available in two sizes: 3.785 L – P/N 10-424 and 9.46 L – P/N 10-425, all of which are available in white.

It is possible to add up to 313.25 L of DEF at this stage. Filling the tank should be stopped as soon as the fluid reaches the top of the fill hose. Do not force any further fluid into the tank at this point.

Faulty Emission Reduction Fluid Tank Heater – TechLink

The date is February 10, 2021. Some 2020 Silverado 1500, Silverado 2500HD/3500HD, Sierra 1500, Sierra 2500HD/3500HD, and 2021 Tahoe, Suburban, Yukon, and Escalade models equipped with the 6.6L Duramax diesel engine (RPO L5P) or 3.0L Duramax diesel engine (RPO L5P) and 3.0L Duramax diesel engine (RPO L5P) may experience problems with the Emission Reduction Fluid Tank heater (RPO LM2). If the heater for the Emission Reduction Fluid Tank is not functioning correctly, the Driver Information Center may display a Service Emission System/Service Exhaust Fluid System message, as well as an illuminated Check Engine MIL.

Tank heating components exposed to Diesel Exhaust Fluid (DEF) and shorting to the pump ground may be the cause of the malfunctioning Emission Reduction Fluid Tank heater.

The Emission Reductant Fluid Supply Pump Module is located within the Emission Reduction Fluid Tank.

16) The control module for the reductant is located outside of the tank.

Measure the resistance at the Emission Reductant Fluid Supply Pump Module (Fig.

If the heater has been exposed to DEF, this would suggest that there is a short to ground.

17 is a diagram of a tetrahedron.

With the Emission Reduction Fluid Tank wiring harness detached, use a Digital Multimeter to measure resistance from pin 9 to pin 14 on the tank’s wire harness.

Pin 9 (1), pin 10 (2), and pin 14 are seen in the figure (Fig.

( 3).

18 is a diagram of a spherical sphere with a rounded bottom.

Continuation of diagnostics in accordance with the applicable Service Information is recommended if both resistance measurements are more than 10M ohm.

To determine if the reductant temperature sensor installed within the Emission Reduction Fluid Tank is below its freeze point, the reductant control module continuously analyzes its readings.

The operation of the reducing pump is suspended for a predetermined period of time to allow the heaters to thaw the frozen DEF in the system. More information may be found in Bulletin21-NA-002, which is available online. – Thanks to Larry Yaw for his assistance.

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