FSB 728-001

Field Service Bulletin
Trucks
Mack Trucks
Greensboro, NC USA
This document replaces service bulletin 728–001, ”Electronically Controlled
Suspension (ECS) Level Sensor Bracket, Replacement”, dated 10.2014.
Date
Group
No.
Release
Page
2.2017
728
001
02
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Electronically Controlled Suspension (ECS)
Level Sensor Bracket, Replacement
CXU
FSB 728-001, Electronically Controlled Suspension
(ECS) Level Sensor Bracket, Replacement
(Febuary 2017)
In some MACK CXU trucks built between 06/01/2012 and 08/31/2014, the Electronically
Controlled Suspension (ECS) level sensor may generate a M150 S13 F3 Diagnostic Trouble
Code (DTC). An M150 S13 F3 DTC causes the suspension to lock into the blocked mode
which may cause damage to the shock brackets, leveling sensor rod and arm. Replacement
of level sensor mounting bracket, rod, and arm is required for the repair procedure outlined
in this document. Additionally, reprogramming, running the appropriate accessory kit, and
calibration of the level sensor is required after installation of the repair parts.
Note: This bulletin does not apply to MACK Trucks Australia.
W7093629
Required Parts (ECS Level Sensor Bracket, Replacement)
Item
Description
Part Number
Qty
1
ECS Level Sensor Bracket
22477383
1
2
ECS Level Sensor Arm
22477385
1
3
Level Control Rod
22383590
1
PV729-FSB728-001_M
USA138282355
Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
Decommissioning the Truck for Repair
You must read and understand the precautions and guidelines in Service Information,
group 70, "General Safety Practices, Electrical" before performing this procedure. If you
are not properly trained and certified in this procedure, ask your supervisor for training
before you perform it.
NOTE: Information is subject to change without notice. Illustrations are used for reference
only and can differ slightly from the actual vehicle being serviced. However, key
components addressed in this information are represented as accurately as possible.
1 Park the vehicle on a flat and level surface.
2 Apply the parking brake.
3 Place the transmission in neutral or park.
4 Install the wheel chocks.
W7086748
5 Disconnect the cable from the battery’s negative terminal.
W3086747
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
ECS Level Sensor Bracket Replacement Procedure
1 Disconnect the wiring harness from the ECS level sensor.
W7093630
2 Remove the fastener securing the level sensor arm to the ECS level sensor.
3 Remove the fastener securing the levels sensor arm to the level control rod.
4 Remove the level control arm.
Note: Do not discard the fasteners. Store the fasteners for reuse.
Note: Discard the level control arm.
W7093631
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
5 Remove the fastener securing the level control rod to the air spring crossbar bracket.
Note: Do not discard the fastener. Store the fastener for reuse.
Note: Discard the level control rod.
W7093632
6 Remove the fasteners securing the ECS level sensor to the mounting bracket.
Note: Do not discard the fasteners. Store them for reuse.
W7093633
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
7 Remove the ECS level sensor from the mounting bracket.
Note: clean the level sensor of any debris and store it for reuse.
W7093634
8 Remove the fasteners securing the mounting bracket to the frame.
Note: Do not discard the fasteners. Store them for reuse.
9 Remove the mounting bracket from the frame and discard.
W7093635
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
10 Install the replacement mounting bracket.
11 Using the stored fasteners, secure the mounting bracket to the frame.
12 Tighten the fasteners to 175 ± 30 Nm (129 ± 22 ft-lb).
W7093636
13 Install the stored ECS level sensor to the mounting bracket.
W7093637
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
14 Using the stored fasteners, secure the ECS level sensor to the mounting bracket.
15 Tighten the fasteners to 24 ± 4 Nm (18 ± 3 ft-lb).
W7093638
16 Install the replacement level sensor arm to the ECS level sensor.
Note: To prevent over-inflation of the suspension air bags, ensure the ECS level sensor
tab and level sensor arm are aligned as shown in the figure below.
W7093639
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
17 Using the stored fastener, secure the level sensor arm to the ECS level sensor.
18 Tighten the fastener to 15 ± 3 Nm (11 ± 2 ft-lb).
W7093640
19 Install the replacement level control rod to the level sensor arm.
20 Using the stored fastener, secure the level control rod.
21 Tighten the fastener to 2.8 Nm (25.0 in-lb).
W7093641
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
22 Install the level control rod to the air spring crossbar bracket.
Note: Ensure the level control rod is installed in the middle hole of the air spring crossbar
bracket as shown in the figure below.
23 Using the stored fastener, secure the level control rod.
24 Tighten the fastener to 2.8 Nm (25.0 in-lb).
W7093632
25 Connect the wiring harness to the level sensor.
W7093642
26 Inspect all four rear upper shock brackets for any signs of bending or deformation.
Note: If any shock brackets show signs of damaged, replace them as needed. If the
shock brackets are not damaged, no replacement is required.
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
Commissioning the Truck for Operation
1 Connect the battery cable to the negative (ground) terminal.
W3086758
2 Using Premium Tech Tool (PTT), clear all DTCs set during the ECS level sensor
replacement procedure.
3 Using PTT, run accessory kit number 85144396.
4 Using PTT, perform a level sensor calibration.
5 Remove the wheel chocks.
W7086759
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Mack Trucks
Field Service Bulletin
Date
2.2017
Group
No.
Release
728
001
02
Reimbursement
This repair may be eligible for reimbursement
if a product failure was experienced within
time and mileage limits of the applicable
Warranty coverage. Reimbursement is
obtained via the normal claim handling
process.
UCHP
Reimbursement
eWarranty
Reimbursement
Claim Type (used only when uploading from
the Dealer Bus. Sys.)
01
01
Primary Labor Code (ECS Level Sensor Bracket,
Replacement)
7281-03-09-01
1.5 hrs.
5411B-ZP-80
1.5 hrs.
Causal Part
21731965
21731965
Labor Code
MACK Trucks North America reserves the right to make any changes in design or to make
additions to or upon its products without incurring any obligations to install the same on
vehicles previously built.
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