Solution K65527708
Friday, March 27, 2020 4:08:20 PM CET

** SOLUTION **
Title

Diagnostic Trouble Codes (DTC) P20EE And P103C, Diagnostic Procedure; REPLACE
S GUIDED DIAGNOSTICS IN PREMIUM TECH TOOL ( PTT ) - US17+OBD16
Through US17+OBD2018 Emissions, Model Years 2018 And 2019

Mack Models
LR , MRU - TerraPro , TE - TerraPro , AN - Anthem , CHU - Pinnacle, Axle back , C

Mack Model

XU - Pinnacle, Axle front , GR - Granite , GU - Granite , PI - Pinnacle

Volvo Models
VNL , VNM , VNR , VAH , VHD

Volvo Model

Emission Standard
Emission Standard

US17+OBD16 , US17+OBD18

Engine family
Engine family

11L Engine , 13L Engine , MP7 , MP8

** SOLUTION **
Cause

Procedures and checks to follow for P20EE and P103C on US17+OBD2016 and
US17+OBD2018 chassis.

Soluti
on

5 JANUARY 2020 UPDATE
There is no longer an eService case required for ANY STEP of the process below.
A case should ONLY BE OPENED if further assistance is required to complete
diagnosis.
If test results determine an SCR replacement is required, A CASE IS NOT
REQUIRED TO ORDER A REPLACEMENT.
Cases submitted solely to request approval to replace an SCR WILL BE
REFUSED.

PRIOR TO PROCEEDING
Review open campaigns for the vehicle and ensure that it is NOT listed for Recalls EC0020a,
EC0022a, EC0022b, or EC0022c.
IF THE CAMPAIGN APPLIES TO THE VEHICLE:
• No diagnostics are necessary.
• No eService case is necessary.

Follow the recall instructions if the vehicle is listed. This solution should only be utilized if the
vehicle is not included in any of the recalls.
CASES AND DIAGNOSTIC TIME REQUESTS OPENED FOR CHASSIS AFFECTED BY
ONE OF THE ABOVE RECALLS WILL BE REFUSED.

If this solution is being reviewed for P225E-00, solution K15560422 must be
utilized FIRST, and this solution should only be followed if the NOx sensors are
determined to be functioning properly. The tests performed in K15560422 do not
need to be duplicated for this solution.

The following checklist should be used for diagnosis of P20EE or P103C on GHG17
chassis instead of Guided Diagnostics.
DO NOT REPLACE ANY PARTS UNTIL ALL ACTIVITIES LISTED IN THIS CBR ARE
COMPLETE.
NOTE: The Malfunction Indicator Lamp ( MIL ) may still be lit even if P20EE shows inactive on a DTC
Readout.

I. Vehicle Emissions Level
Review the vehicle emissions level
• Details can be found in the Product Details box on the Product tab in PTT as seen below:

• If the vehicle is US17+OBD16 or US17+OBD18:
- Perform Sections II and III below.
- If this is the vehicle's FIRST VISIT and there are no contributing DTCs: Perform a sulfur regen
and release the vehicle.
- If the vehicle has been in previously for this issue: Complete all sections below.

II. Vehicle History

- The following information should be obtained prior to beginning diagnosis.
• Is this the chassis's first visit to the dealer for either of these codes?
• Have there been any previous failures or problems that may have caused problems with the Exhaust
Aftertreatment System (EATS)?
Examples:
- Turbocharger failure
- EGR Cooler failure
- Coolant passage through the exhaust
- Excessive fuel through the exhaust (Injector failure, AHI failure)
- DPF failure
- Contaminated DEF

III. Check the DTC Readout
- Are there any other NOx sensor DTCs present?
• P225E and P0422 are very similar to P20EE and should be checked with the same steps below.
• Any other NOx sensor codes may suggest intermittent NOx sensor failure.
- Are there any codes present for other engine components that would indicate an issue contributing to
or causing either P20EE or P103C?
• Examples:
EGR System
Fuel System ( Includes AHI)
Turbocharger/Boost
DPF
Exhaust temperature

IV. Check SCR Efficiency Evaluations
- SCR Efficiency values can be found in Premium Tech Tool ( PTT ) Operation 2589-08-03-05
Aftertreatment Selective Catalytic Reduction (SCR) System.

• The last five efficiency evaluations are displayed as shown in the screenshot above.
If all five tests are below the fault limit, SCR conversion has been poor for an extended amount of
time.
If only one or two are below the fault limit, conversion is only intermittently poor.
- Information on driving conditions when the poor conversion is occurring may provide insight
into the cause of the codes.

V. SCR System Checks
All steps below should be performed to verify proper function of each component.
1. Check DEF quality with a refractometer
2. Physically check for any contamination in the DEF tank
• Examples
- Dirt or Debris
- Coolant
- Water
- Fuel
- Oil
3. Physically inspect the DEF Dosing Valve, Diffuser Pipe, and SCR Inlet for crystallized DEF
• Ensure there is no significant/excessive crystal buildup in any component.
NOTE: A small amount of crystal accumulation is normal.
• If significant accumulation is noted clean it as first step and then ensure that the DEF dosing valve
is correctly installed with all gaskets and clamps positioned properly.
4. Perform DEF Dosing Test 2 to confirm proper function
• Located in Operation 2589-08-03-05 Aftertreatment Selective Catalytic Reduction (SCR) System.
Test B from the first screen of the operation
• Test two is the Small Dosing Test

The test should be run twice and results noted to an accuracy of 2 milliliters
Nominal Volume is 55 mL
- Acceptable range is 55 mL ± 3 mL
5. Check the Main Software part number for the Engine Control Module (EMS)
• Make a note of the number. It will be used in the next step.
6. Run a NOx Conversion, Operation 2549-08-03-03.

Read all of the parts of this step prior to performing
the test to prevent repeated steps.
This test checks the function of both NOx sensors. It d
oes not evaluate SCR efficiency.

• While running NOx conversion test, if any new NOx sensor codes are logged (Egs: P220E-93, P220F93), make sure to troubleshoot those codes.
• Inlet and Outlet NOx Sensor values should be close to each other at high engine speed (last portion of
the test) as shown below.
• If during the test difference between NOx sensors are greater than 10%, it is recommended to replace
the sensor reading the higher value and re-do the test.
The likelihood that both sensors require replacement at once is low. Replacement of both sensors at once
should not be considered immediately unless affected by an upstream failure.

• If the vehicle has EMS Software Part Number 23470183 or 23470187: Refer to the comments below:
EMS Main Software Part Numbers 23470183 and 23470187, used for US17+OBD18 emissions, has
a bug that allows DEF dosing to continue during the NOx conversion test. This causes continued low
Outlet NOx sensor values as seen in the screen shot below and prevents the desired behavior shown
above.

In this instance,review earlier sections of the test to ensure that both sensors are responding to
changes in the same manner. Examples of different stages to review are shown below.
COMPARISON SHOULD BE DONE WHEN BOTH NOx SENSORS ARE READING BELOW
600 PPM.

VI. eService Case
If further assistance is required to complete diagnosis and an eService case is opened, the case MUST
INCLUDE:
1. The vehicle history as described in Section I.
2. A complete DTC Readout from the time of the vehicle's arrival.
3. Screenshots of:
• SCR Efficiency values as shown in Section III
• The NOx Conversion Test as shown in the picture in Section IV.
NOTE: Refer to CBR Solution K52225504 - Methods For Taking A Screenshot

4. A description of findings for each item checked in Section IV, including numerical values for the dosing

tests ("Good", "Okay", "In spec", etc. are not acceptable values).

Internal comments (BO)

For OBD2019 (Truck MY2020, with VIN number ending with LNxxxxxx or
LMxxxxxx), there is a new CBR.
For GHG 2017 and 2018 cases with P20EE (and /or P103C) evaluate following 6 items:
1. SCR efficiency looks bad (all 5 evaluations hovering around or lower than 80%)
2. NOx conversion just before shutdown looks good (Both NOx sensors are within
10% of each other and values between 200-500ppm). When in doubt replace
sensor reading higher value (higher by atleast 10%).
3. DEF quality inspection is good
4. Dosing flow test is good (52-58cc)
5. No other relevant fault codes (EGR system, fuel system)
6. Prior visit got Sulfur regeneration completed and truck is back within 2 weeks
for same issue or Truck has P103C (SCR inducement code).

If all 6 of the above items are OK, we are OK with replacing SCR (2 Box). Only
vehicles having P103C or customers who decides to park the vehicle when MIL is ON
(for P20EE) would be considered as requiring one box replacement for Mack vehicles
(due to parts shortage of one box mack). Please make sure to collect all the data as per
checklist prior to recommending SCR replacement.
Solution visibility

Dealer distribution

Function(s)/component(s) affected
Function affected

Diagnostic tool , DEF Dosing , SCR

Function Group
Function Group

254 catalytic converter; exhaust emission control equipment , 258 emissions aftertreatment

Customer effect
Main customer effect

regeneration , diagnostics/methodology , efficiency/abnormal behavior , fault code
/display

Fluid implicated

Diesel Exhaust Fluid (DEF)

Fault Codes And Error Codes
OBDII Diagnostic Trouble
Codes (P, U, B Format)

P0422-00 , P103C-00 , P20EE-00 , P225E-00

Conditions
Vehicle operating mode
Frequency of occurrence of
problem

when driving , when stationary
random

Administration
Author

UT0031H

Dealer ID

UT0031H

Last modified by

RU4469V

Creation date

05-06-2018 17:06

Date of last update

22-01-2020 19:01

Review date

01-10-2018 00:10

Status

Published

Average score

3.75

Number of scores

4

NA_Reviewer

ut0031h

NA_Author_Group

GTT

UNCONTROLLED COPY. Printed document is for temporary use only and should not be retained.