Side Guard Trailer Detection

TSB-54-381-FTL

Creation Date: 2026-03-17

Engine or Vehicle Affected:

» New Cascadia

Warranty applies to this described condition. See the warranty information at the end of this bulletin.

Described Condition

New Cascadia vehicles built with Detroit Assurance 5.0 with Active Side Guard Assist were built without an
installed trailer air pressure switch. This causes the Active Side Guard Assist system to always respond as if a
trailer is present. The cluster a warning light may turn on when the vehicle is bobtail and the side guard is looking
for a trailer.

New Cascadia is missing a pressure switch that allows the Single Signal Actuating Module (SSAM) to determine
whether a trailer is connected or not.

Side Guard Assist (SGA) always assumes that the truck is connected to a trailer. When a truck is running bobtail,
the radar does not adjust to End of Frame (EOF) detection. This leads to false warnings when running bobtail.

Before the repair is completed, a ‘with trailer’ gray indicator, as shown in Fig. 1, is active while bobtail. This
indicates that the full trailer length of SGA is active. After the repair is completed, a ‘without trailer’ gray indicator,
as shown in Fig. 2, is active while bobtail. This indicates that the system is correctly adapted to the absence a
trailer.

Fig. 1, ‘With Trailer’ Gray Indicator

Fig. 2, ‘Without Trailer’ Gray Indicator

Parts Table

Table 1, Parts Table

Part Number Part Description Quantity
A66-16596-000 HARNESS-FIFTH 1
A66-23214-000 HARNESS, JUMPER 1

12-31615-000 PRESS, SWITCH 1
23-14416-001 TEE-BR, PTC 1

Table 1, Parts Table

Procedure
1. Park the vehicle on a level surface. Turn the keyswitch OFF, place the transmission in neutral, and set the park brake. Chock the tires.

w Note: ELECTRICAL SHOCK

To avoid injury from electrical shock, use care when connecting battery cables.
The magnetic switch studs are at battery voltage.

2. Disconnect any batteries connected to the dashboard center panel.

3. _) Remove the center dashboard panel to access the sSAM. See Fig. 3. For information on removing dashboard covers, see the appropriate
procedure:

o harp://6961fed6d5471e51fcb57642/pr/ORIGINAL/Freightliner-0000211877%2054-

381%20Side%20Guard%20 Trailer%20Detection/0000072409.xml in the New Cascadia Workshop
Manual

o harp://6961fed6d5471e51fcb57642/pr/ORIGINAL/Freightliner-0000211877%2054-
381%20Side%20Guard%20 Trailer%20Detection/0000139177.xml in the 5th Gen Cascadia Workshop

Manual

01/30/2026 549058

Fig. 3, Center Dashboard Panel Removed

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4. Once the dashboard lower panel is removed, locate and splice the air T with a sensor into the orange trailer delivery line. See Fig. 4 and
Fig. 5.
01/26/2026 549056

38" ORANGE. TRAILER DEL 3 SILVER, EXHAUST
(ear)

02/02/2026 f549055

1. VM1360 Lead Serial for Werner Fleet 3. Splice in 12-31615-000 and 23-14416-

2. Module 882 Missing Pressure Switch 001 Into Orange Line
Fig. 5, Installation Drawing

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5. —) Assemble the air fitting and pressure sensor along with the harness as shown in Fig. 6 and Fig. 7.

01/30/2026 a - 549060

6.

7.

Fig. 6, Air T with Sensor and Harness, Jumper Harness

01/30/2026 549068

Fig. 7, Sensor and T with Harness Installed

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Cut into the T. Splice the T to the orange trailer line. See Fig. 8 and Fig. 9.

Se
oe > ¢€ :

ms
3/8" BLACK, TRAC DEL * a
882
002
eee ar en ee a (co
3/8" RED, SEC SUR. SS eo f
882 = 2 “i
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tr —2" ! . s _ i
882
_ 056 3/8” ORANGE, TRAILER DEL 3/8” SILVER, EXHAUST
3 3/8” GREEN, PRI SUP 882 882
TEE 412 443
PS1
01/30/2026 #549069
Fig. 8, Sensor Installation Drawing
0: |GND_INT_DASH_O SP_GND-C_14 = :

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02/02/2026 549070

Fig. 9, Wiring Diagram with Pin Locations

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Route the red and white wire following the dashboard harness to the sSAM. See Fig. 10.

01/30/2026 549066

Fig. 10, Routing the Red and White Wire

Locate sSAM connector X7. See Fig. 11.

MUX
REF MOD 32A

FRONTWALL
REF MOD 824

K029|

VIEW K
LOOKING AT FRONTWALL TUNNEL FROM INSIDE CAB

Ko24
H_ECU_SSAM_X7_1A 23
H_ECU_SSAM_X8 1A K022 |
H_ECU_SSAM_X9_1A K021
H_ECU_SSAM_X10_1A K020|
CTS] H_ECU_SSAM_X11_1A K020|
DASH_O_RTERM SAM_BCA 2B] 360
H_ECU_SSAM X13 1A K016|
01/30/2026 549067

02/03/2026 549064

Fig. 12, Pin Lock Released

10. © Insert the red and white wire into pin location 11. See Fig. 13.

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Fig. 13, Pin Location 11

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11. © Press the pin lock back into the locked position. Connect the connector to the sSAM.

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## Note: The ground splice may not be identified as 13N or GND-C on any of the
connectors. To locate the correct ground splice, access the Vehicle Power
Distribution Module (VPDM). See Fig. 15.

12. — Locate the 13N ground splice pack in the dashboard harness bundle. See Fig. 14.

——
REFERENCE REF

DESIGNATOR MOD
748
74B
74D
74D
74D
74D
74D

708 |
73
73F
28G
28G

ND_INT DASH O SP_GND-C 1A 28G

LOCK DASH O AUDIO GND 1A 738

ND_INT DASH O SP _GNDE 1A 28G

01/30/2026 : (549059

13.

14.

15.

16.

Fig. 14, Ground Splice Pack Installation Drawing

01/30/2026 549063

Fig. 15, Splice Packs

Remove the VPDM from the mounting support.

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Remove the VPDM back cover to access the J8 ground connector. See Fig. 16.

01/30/2026 549062

Fig. 16, VPDM J8 Connector

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Remove the J8 connection from the back of the VPDM. Check the continuity on the J8 harness until J8-C2 rings out with the chosen

splice pack. Check the continuity on the splice packs until 13N is located.

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Once the ground splice pack is located, remove the pin lock. See Fig. 17.

01/30/2026

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Re gr 10: BuIL

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549065

Fig. 17, Splice Pack Unlocked

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17. Inset the black and white wire from the sensor harness into the splice pack.

18. © Install the lock.

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19. Install the removed J8 connector of the VPDM. Install the VPDM back cover.

20. —) Install the VPDM on the dashboard support.

21.) Tie back and secure the ground splice packs.

22.) Install the dashboard panels as required.

Warranty

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This procedure is warrantable only if the described condition exists and the repair is performed within the
applicable base or extended coverage warranty period. If a failure is not found, this procedure is considered
preventive and warranty does not apply.

See Table 2 for OWL VMRS codes and labor allowance information. Enter this service bulletin number in the
Service Bulletin # field.

Table 2, OWL VMRS Codes and Labor Allowance

Primary Component Cause Correction SRT Description Hours
Failed Part Code Code Code Code P
12-31615-000 | 053-025-002 14 14 882- PRESSURE SWITCH, INSTALL, 0.5
5010A SIDE GUARD ASSIST
Table 2, OWL VMRS Codes and Labor Allowance
Note:

F26
F16
F35
F36
REPLACE

Document Number: 0000211877
Topic Publication Date: 2026-03-18