Countries:

CANADA, UNITED STATES Document ID: IK1201511

Availability:

ISIS, FleetISIS, IsSIR

Revision:

0

Major System:

ENGINE

Created:

3/19/2025

Current Language: English

Last Modified: 3/26/2025

Other Languages: NONE

Author:

Viewed:

Brandon Heisler

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1

Title : Supplemental A26 MAF Fault Diagnostics
Applies To : All A26 Engines

CHANGE LOG
Please refer to the change log text box below for recent changes to this article:
03/26/2025 - Initial Article Release

**PLEASE COMPLETE ALL PUBLISHED DIAGNOSTICS BEFORE PERFORMING THESE STEPS.**
The diagnostics within this document are supplemental diagnostic steps only. This article is intended to be followed once all published diagnostics have been
exhausted with no current repair direction or solution. Failure to follow published diagnostics can result in improper diagnostics being performed, and can
also result in extended downtime for the customer. Technical Service Support teams have created this article for a short-term solution while pending
published diagnostics are enhanced and updated. Once those diagnostics have been updated, this article will be retired. Always reference published
manuals, FCAPs, and GUIDE sessions before performing the steps below.

DESCRIPTION
This document will guide users through supplemental diagnostics for SPN 132, Mass Air Flow, fault codes.

SYMPTOM(s)
MIL
MAF calibration will not complete.

Diagnostic Trouble Code(s) & Dashboard Indicator Light(s):
DTC/Light
2017 A26 ESN 4500000 - 4599999

Description

SPN 132 FMI 0

Engine Intake Air Mass Flow Rate: Data Valid But Above Normal Operational Range
- Most Severe Level

SPN 132 FMI 13

Engine Intake Air Mass Flow Rate: Out Of Calibration

SPN 132 FMI 16
SPN 132 FMI 18

Engine Intake Air Mass Flow Rate: Data Valid But Above Normal Operating Range Moderately Severe Level
Engine Intake Air Mass Flow Rate: Data Valid But Below Normal Operating Range Moderately Severe Level

SPN 132 FMI 20

Engine Intake Air Mass Flow Rate: Data Drifted High

SPN 132 FMI 21

Engine Intake Air Mass Flow Rate: Data Drifted Low

2021 A26 ESN 4600000 - 4699999

Description

SPN 132 FMI 0

Engine Intake Air Mass Flow Rate: Data Valid But Above Normal Operational Range
- Most Severe Level

SPN 132 FMI 13

Engine Intake Air Mass Flow Rate: Out Of Calibration
Engine Intake Air Mass Flow Rate: Data Valid But Above Normal Operating Range:
Moderately Severe Level
Engine Intake Air Mass Flow Rate: Data Valid But Below Normal Operating Range Moderately Severe Level

SPN 132 FMI 16
SPN 132 FMI 18
Customer Observations or Concerns:
MIL On

SPECIAL TOOL(s) / SOFTWARE
Tool Description
SDS

Tool Number
N/A

Comments
N/A

Instructions
Review Introduction to SDS

Tools Resource Center

SERVICE PARTS INFORMATION
Please consult with the parts department for current service part numbers.

DIAGNOSTIC STEP(s)
2017 A16 ESN 4500000 - 4599999
2021 A26 ESN 4600000 - 4699999

2017 A26 ESN 4500000 - 4599999
Step
#1

Confirm base diagnostics have been completed.
Review FCAP/GUIDE and symptom-based diagnostics from the diagnostic
manual:

Decision
Yes.

Did the applicable FCAP/GUIDE or symptom-based diagnostics identify a repair
path?

Follow the repair path established by the
published diagnostics.

NOTE: If a symptom is associated with the fault code, the diagnostics for that
symptom should be performed before moving on to the next step.

No.
Proceed to step 2.

Step

Verify ECM calibration

Decision

Confirm the ECM calibration is up to date:

Yes.

Is the ECM calibration SV*B or greater?

Proceed to step 3.

No.
#2

Step

Update the ECM calibration and then retest for the issue. If the issue persists,
proceed to step 3.

Review health reports
If the ECM calibration was already up to date, review the health report history
from the past 100 engine hours. Check for VGT (641) fault codes.

Decision
Yes.
Proceed to step 4.

If the ECM calibration was updated, confirm a VGT (641) fault did not log
pending or active when re-testing:
Were any VGT faults found, without associated repairs?

#3

No.
Proceed to step 5.

Step
#4

Inspect the VGT

Decision

Disconnect the VGT actuator linkage from the turbo. Cycle the turbo vanes by Yes.
hand both cold and hot, to check for binding/sticking:
Replace the turbo assembly, perform a
Was any binding or sticking found when sweeping the VGT (turbo) vanes?
MAF calibration, and then re-test for the
issue. If the issue persists, proceed to
NOTE: Do NOT turn the key-on while the actuator arm is disconnected from
step 5.
the turbo, as this can cause damage to the assembly.

No.
Proceed to step 5.

Step

Confirm EGRV operation
Perform an Air Management Test and inspect for EGRV operation per
IK1201492:

Decision
Yes.
Replace the EGRV, perform a MAF
calibration, and re-test for the issue. If the
issue persists, proceed to step 6.

Was a failed EGRV identified?

NOTE: If the EGRV was replaced,
another AMT should be completed
before proceeding to step 6.
#5

No.
Proceed to step 6.

Step

Validate airflow.

Decision

At the same point in the graph, the EGRV was checked (half way between test Yes.
start and EGRV command position), verify the Mass Air Flow, Intake Manifold
Pressure, and Exhaust Back Pressure readings:
Proceed to step 7.
Is MAF below 1000 kg/hr, IMP below 10 psi, and/or EBP below 20 psi?

#6

No.
Proceed to step 8.

Step
#7

Locate the source of low-airflow.
Perform smoke testing on the intake and exhaust, and CAC pressure testing,
to determine if a leak is present:
Was a leak identified?

Decision
Yes.
Perform repairs/replacements as needed
and then re-test. If the issue persists,
proceed to step 9.

No.
Proceed to step 9.

Step

Validate airflow.
At the same point in the graph, the EGRV was checked (halfway between test
start and EGRV command position), verify the Mass Air Flow, Intake Manifold
Pressure, and Exhaust Back Pressure readings:
Is MAF above 1400 kg/hr or IMP above 25 psi, with EBP above 45 psi and/or
DPFDP above 0.4 psi?

Decision
Yes.
Drop the DOC and DPF for inspection.
Inspect them per the re-use guidelines to
determine if they can be reused or if they
should be replaced. If they can be
replaced, have the DOC cleaned, and the
DPF cleaned AND baked. Once repairs
are completed, re-test for the issue. If the
issue persists, proceed to step 9.

#8
NOTE: International no longer requires
or provides iApprovals for DOC or DPF
replacements.

No.
Proceed to step 9.

Step

Check for biased sensors.
Perform a 5-minute KOEO signal monitor session with SDS. Review the
session and confirm the EBP sensor, IMP sensor, and MAF sensors are
reading 0 with the engine off:

Decision
Yes.
Proceed to step 11.

Are all of the listed sensors reading 0 at KOEO?

#9

No.
Proceed to step 10.

Step

Confirm the circuits to the identified biased sensor.

#10 Perform connector body, pin drag, pin inspections, and circuit checks at the
biased sensor (connector and pins should be inspected at each connection
point):
Was a failed connector/pin identified, or was a failed circuit identified?

Decision
Yes.
Repair/replace the failed connector/pin or
replace the engine sensor harness and
re-test. If the issue persists, proceed to
step 11.

No.
Replace the biased sensor and re-test. If
the issue persists, proceed to step 11.

Step

Perform a regen.

Decision

Perform a regen and review per IK0700123:

Yes.

Was an issue found during the regeneration diagnostics?

Perform repairs as needed and then retest for the issue. If the issue persists,
proceed to step 12.

#11

No.
Proceed to step 12.

Step

Validate Airflow

Decision

Perform a 0-60/Lugdown and road test during a signal monitor session in SDS. Yes.
Review DPFDP:

Proceed to step 13.

Is DPFDP lower than 0.5 psi throughout the entire snapshot?

No, DPFDP is greater than 0.5 PSI.
If the DPF was already cleaned AND
baked (not just cleaned), replace the DPF
and re-test. If the issue persists, validate
the results of this step with a new/current
0-60/Lugdown.
If the DOC and DPF have not been
inspected per the reuse guidelines, do so
at this time. If they pass re-use, have the
DOC cleaned and the DPF cleaned AND
baked. If they were not cleaned AND
baked before this step, another 060/Lugdown and this step should be