NHTSA ID Number: 10178266
Manufacturer Communication Number: 20NA071
Summary
This technical bulletin provides repair information to correct a customer concern of the Service Engine Soon Lamp illuminated and/or Service Power Brake Assist message displayed, with DTCs P0557 or P0558 Stored.
17 Affected Products
Vehicles
| MAKE | MODEL | YEAR |
BUICK | ENCLAVE | 2018-2020 |
| CADILLAC | XT5 | 2017-2020 |
| CADILLAC | XT6 | 2020 |
| CHEVROLET | BLAZER | 2019-2020 |
| CHEVROLET | TRAVERSE | 2018-2020 |
| GMC | ACADIA | 2017-2020 |
SEOCONTENT-START
Service
Bulletin No.: 20-NA-071
Date: June, 2020
TECHNICAL
Subject: Service Engine Soon Lamp Illuminated and/or Service Power Brake Assist Message
Displayed, with DTCs P0557 or P0558 Stored
Brand:
Model:
Model Year: from to
2018
VIN:
from to
Holden
XT5 XT6
Blazer Traverse
Acadia Acadia
2017
2020
2019
2018
2017 (VIN N)
2019
Involved Region or Country Additional Options (RPOs)
Condition
Cause Correction
North America, Europe, Russia, Middle East, Israel, Palestine, Chile, Ecuador, Peru, Japan, Korea
Equipped with BRAKE SYSTEM-POWER, FRT & RR DISC, ABS, 17″ (J61)
Some customers may comment that the Service Engine Soon (SES) lamp is illuminated and/or the
Service Brake Assist message is displayed on the Driver Information
Center (DIC).
A technician may find DTC P0557 or P0558 stored.
There is potential for EMI in the engine harness negatively impacting the signal from the vacuum
sensor.
The cause of the condition may be poor terminal tension at the B19B Brake Booster Vacuum Sensor
and/or the wiring from the brake vacuum sensor to the Engine Control Module (ECM).
Replace the power brake booster vacuum hose and install a new external wiring harness, following
the Service Procedure below.
Service Procedure
Note: Examples of the 3 different designs for the power brake booster vacuum hoses are shown in
the
graphics below.
LFY Hose
LGX Hose
5549611
LCV Hose
Note: Please print the Matrix below and use it for
5549615
reference while completing steps #16-22 of the Service Procedure,
Matrix
Application/Circuit/Wire Color/ECM Connector/ECM Terminal
New wire harness
lead tag ID’s Wire Color
6270
Vt/Ye
6271
Gn/Vt
6272
Bk
5549612
LGX/LFY – V6 only
Circuit Number Body Harness Color ECM Connector ECM Terminal
Acadia, XT5, XT6, Traverse, Enclave, Blazer
6030 6031 2151
Ye/Vt Ye/Rd Bk/Wh
X1 X1 X1
65 45 44
LCV – 4 Cyl. only
Circuit Number Body Harness Color ECM Connector ECM Terminal
Acadia
6030 6031 2151
Ye/Vt Ye/Rd Bk/Wh
X1 X3 X3
32 15 20
LGX – V6 only
Circuit Number Body Harness Color ECM Connector ECM Terminal
Holden Acadia
6030 6031 2151
Ye/Vt Ye/Rd Bk/Wh
X1 X1 X1
65 45 44
Matrix
LCV – 4 Cyl. only
Circuit Number Body Harness Color ECM Connector ECM Terminal
Holden Acadia
6030 6031 2151
Ye/Vt Ye/Rd Bk/Wh
X1 X3 X3
32 15 20
1. Remove and discard the power brake booster vacuum hose. Refer to Power Brake Booster Vacuum
Hose Replacement, in SI.
5549616
Note: The top graphic shows the LGX connector intact; the bottom one shows the LFY wiring already
cut.
5549617
2. Locate the power brake booster vacuum sensor electrical connector. Fold conduit back and cut
off connector, leaving approximately 5.0 cm (2.0 in) of wiring on the engine harness side.
3. Tape the cut wiring end to the engine harness. These wires will no longer be used.
5549619
Note: Not all applications will have a cover on the connector.
4. Remove conduit and cover from the old connector.
5549621
6. Install old conduit piece, connector cover and apply abrasion resistant tape over the conduit
up to the new connector end.
7. Install the new power brake booster vacuum hose. Refer to Power Brake Booster Vacuum Hose
Replacement, in SI.
8. Plug in the new harness to the power brake booster vacuum sensor electrical connector.
Note: It is not necessary to reposition the radiator surge tank on all applications.
9. Remove the mounting bolt and reposition the radiator surge tank away from the cowl. Refer to
Radiator Surge Tank Replacement, in SI.
5549620
5. Apply tape to connector end of the new harness, leaving enough length as was on original
connector to allow for 90 degree elbow bend, if applicable.
5549622
5549624
Note: The LFY harness routing is shown in the top graphic, the LGX routing is shown in the bottom
math file. The routing for LCV is similar to the routing of the LGX.
10. Start routing the new harness alongside the engine harness.
14. Using terminal release tool J-38125–12A, or similar tool, remove the terminated leads from
circuits #6030, #6031 and #2151 from the X1 connector.
5549627
11. Unplug the X1 ECM connector (blue) from the ECM, for LGX and LFY. Also unplug ECM connector X3
on LCV engine applications.
5549626
5549629
Note: In this step, do NOT cut the terminal off of circuit #2151 (circled in yellow in the
graphic above).
15. Cut off the terminated leads that were in circuits #6030 and #6031 and fold and tape off the
ends
12. Cut back some of the tape on the connector wiring to expose more wiring.
13. Using a suitable pry tool, remove the cover from the connector.
(circled in red in the graphic above). These circuits will no longer be used.
21. Strip the end of all three of these wires, leaving enough length to make a splice in the butt
connector.
22. Twist the engine harness side of circuit #2151 with the new harness #6272 and insert in the
butt connector and crimp.
23. Insert circuit #2151 wire from the ECM connector into the butt connector and crimp.
24. Apply heat to shrink and seal the butt connector to complete the splice. Refer to Wire to Wire
Repair, in SI.
5549630
16. Locate the wire labeled #6270 on the new harness and install that terminated lead into the
location in connector X1, where circuit #6030 was located.
17. Locate the wire labeled #6271 on the new harness and install that terminated lead into the
location in connector X1, where circuit #6031 was located.
18. Locate the wire labeled #6272 on the new harness and install that terminated lead into the
location in connector X1 where circuit #2151 was located.
5549632
25. Reposition the wiring to the connector and using abrasion resistant tape, apply tape up to the
flip door of the ECM connector.
26. Reinstall the cover to the connector.
27. Reconnect the ECM connector(s).
5549631
Important: There are multiple ground circuits tied to ECM ground circuit #2151 and the existing
vehicle harness wire MUST be spliced into the new harness.
19. Cut the new harness wire labeled #6272 approximately 7.6 cm (3.0 in) from the ECM connector
body.
20. Cut the engine harness ground circuit #2151 approximately 7.6 cm (3.0 in) from the ECM
connector body.
5549633
Bulletin No.: 20-NA-071 June, 2020
Page 7
Note: Graphic shown above is LFY harness routing.
5549634
Note: Graphic shown above is LGX harness routing, with LCV being similar.
Important: It will be necessary to coil the extra wire length. Ensure the wire is tied back away
from any sharp edges or moving parts that could cause damage to the harness.
28. Secure the new harness to the engine wiring harness using at least 5 or 6 tie straps.
29. Check and clear any DTC’s, as necessary.
Parts Information
Use the VIN and refer to the GM Electronic Parts Catalog (EPC) to determine the proper part to
order.
Causal Part
N/A X
N/A
Description
WRG HARN
HOSE ASM-P/B BOOS VAC
SALMON SPLICE
Part Number
84441605
84265637
84341899
84210413
19300089
Qty
1
1
1
Warranty Information
For vehicles repaired under the Bumper-to-Bumper coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor Operation Description
Labor Time
2486068*
Replace Power Brake Booster Vacuum Hose Assembly and Install Wiring Harness
LFY – 1.0 hr
LGX or LCV – 1.3 hrs
*This is a unique Labor Operation for Bulletin use only.
Version Modified
3
Released March 20, 2020.
Released April 16, 2020 – Corrected Salmon Splice Part Number.
Released June 01, 2020— Changed all sections of matrix that reference Circuit 6032 – Bk/Ye – to
2151 – Bk/Wh.
GM bulletins are intended for use by professional technicians, NOT a “do-it-yourselfer”. They are
written to inform these technicians of conditions that may occur on some vehicles, or to
provide information that could assist in the proper service of a vehicle. Properly trained
technicians have the equipment, tools, safety instructions, and know-how to do a job properly and
safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or
that your vehicle will have that condition. See your GM dealer for information on
whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN
CERTIFICATION
SEOCONTENT-END
1 Associated Document
Manufacturer Communications
Bulletin No.: 20-NA-071
Date: June, 2020
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