3% (QLS) 3% with Cover (QLS) | 1% with Cover (QLS) | 1% with Cover (QLS) TANK SIZE
/Gen1 /Gen 1.1 /Gen2 | REMAN
4097721691 4254212091 4163689091 5012176R91 5 GAL
4097722C91 4254211091 4157846C91 5012171R91 7 GAL
4097723691 4254213091 4163692¢91 5012172R91 9.5 GAL
4097724C91 4254214091 4163693C91 5012173R91 12 GAL
4097725091 4254216091 4163694091 5012177R91 15 GAL
15.5 GAL
“prose 4254216C91 4163695091 501217491 16 GAL
23 GAL
10.6GAL
10.6GAL-LN.
oni 4254210091 4140918091 5012175R91 15.9GAL
15.9GAL-LN
25.2GAL
3% 3% with Cover 1% with Cover 1% with cover TANK SIZE
1Gen 1 (FLS) 1 Gen 1.1 (FLS) 1 Gen 2 (FLS) | Reman (FLS)
409971591 4254200091 4163697691 5012178R91 7 GAL
4099716C91 4254201091 4163698C91 5012179R91 9.5 GAL
15.5 GAL
“(presiar) 4254202091 4163699091 5012180R91 16 GAL
23 GAL
10.6GAL
10.6GAL-LN
oar 425420391 4163700C91 15.9GAL
15.9GAL-LN
25.2GAL

SSI DATE CODE
AND. SERTA\
NUMBER

ssI
PART
NUMBER

NAVISTAR,
PART.
NUMBER

Figure 3a: QLS Identification

[Figure 3b: QLS Cover Update

|All QLS sensors have been updated to include a cover to prevent
IDEF ingress into the sensor assembly. This went into production:

* Tulsa: 9/21/2020
© SpringField: 11/1/2020
« Escobedo: 11/21/2020

Note: 3% vs 1% sensors are in reference to the sensors DEF quality
accuracy (i.e. sensor can read DEF quality at -+3% or -+1%). The
cover is the corrective action not the change in sensor accuracy.

DIAGNOSTIC STEP(s)

component.

‘The EPA and CARB has only granted Navistar limited use of the QLS emergency calibration as it
applies to the faults listed in the table above and diagnostic steps outlined in this article. The use
of this calibration in any other circumstances could be considered tampering of an emission level

part must be replaced, and the calibration can NOT be installed.

This procedure is only intended to be used if a QLS is not available. If the QLS is available the

IStep/Action

Decision

DIAGNOSTIC:

ESN marked with the TRP #12489 on Cummins Quickserve?

lls the Vehicle marked with an AFC #21901 on the Navistar Service Portal or the

If the vehicle is not marked with the TRP then there is not a calibration available at

Yes. Go to step 2

INo. The vehicle will not qualify for the
ITRP or AFC. Follow standard
ldiagnostics. This letter does not apply

Does the vehicle present with only QLS communication faults listed in the
fault code section of this article?

Note: Other aftertreatment components share the same aftertreatment datalink as

it is likely not a QLS

the QLS, when other AFT components log communication fault codes with the QLS

this time
1
Step/Action Decision
DIAGNOSTIC:

Yes. Go to step 3

INo. The vehicle will not qualify for the
|TRP or AFC. Follow the diagnostics for
Ithe other fault codes present.

Step/Action

Decision

DIAGNOSTIC:
Follow the circuit diagnostics outlined HERE.

Note: The flow test of the DEFTHV should NOT be performed if the calibration
is being installed.

Yes: Leave the QLS disconnected and
proceed to step 4

No. The vehicle will not qualify for the
ITRP or AFC. Perform the necessary non
QLS replacement repairs

3 |Did the circuit diagnostics lead back to this article and step 4?
IStep/Action Decision
DIAGNOSTIC: lYes. The vehicle will not qualify for the
ITRP or AFC. Please proceed with flow
lls there a replacement QLS available? testing the DEFTHV and replacing the
IQLS.
Refer to the table above for QLS part numbers. No. Refer to the repair steps listed below
4

cuit Eo E==

bb

ca Gir ass SHE 7
; DEFT = ORFS (ORL? _EFLIT 1 ee Head unt PFO /OPFOP -
i (seston) )— reme) DEF Supey i 5 + pasar
i DEF Tank Harness R

ee

Sener oie

No, Out

Exhaust Harness

[Figure 4: General QLS Wiring Diagram

[Note’ Refer to chassis circuit diagrams for detailed information

REPAIR STEP(s)

In some failure conditions the QLS sensor can produce faults intermittently, it is recommended that the sensor be removed electrically from the
chassis harness to prevent this as it can lead to additional warnings and de-rate events. This can be performed simultaneously with the
programming event. The intent of this procedure is to disconnect the sensor electrically and seal the harness to prevent moisture and corrosion in
the chassis harness connector for when the QLS is replaced under future activity. The QLS must remain in the tank and connected to the DEF
and coolant lines as they are still required for vehicle operation.

1. Ensure the QLS is disconnected from the chassis harness. If the sensor is still connected it could result in shorting of the power circuit.

2. Using wire cutters, cut the QLS pigtail hamess as least four inches from the connector (Refer to figure #5). Once cut the pigtail can be moved
to a bench for ease of installation.

Note: At no point is the QLS removed from the DEF tank during this procedure.

[Figure 5: QLS Pigtail Modification |
[Item 1: QLS Pigtail