August, 2026

Bulletin No.: PIT6503C

• ADAS features (Forward Collision Alert, AEB, Lane Keep Assist, etc.) operating intermittently or inoperative.
• Various communication and control module DTCs set as Active or History, including
but not limited to:
− U1615 / U1616 – Lost Communication with B174W on CAN Bus 2 or CAN Bus 8.
− U197A – Ethernet Time Synchronization Signal Invalid (set by B174W ).
− U0499 – Invalid Data Received from Telematics Control Platform Module (set by
B174W ).
− U0235 – Lost Communication with Forward LRR sensor (set by B174W ).
− B1A05 – B174W MCU Missing Calibration (set by B174W ).
− U3000 – Control Module set by B174W or other ECUs.
− Other network loss-of-communication DTCs involving K56 Serial Data Gateway
Module and related ECUs as referenced in SI.
In some cases, vehicles may have had the front camera replaced previously during the
same visit without full completion of diagnostics and prescribed service instructions, with
no resolution of the customer concern.
Engineering analysis and field reviews have identified that many B174W Front View
Camera module replacements are the result of incomplete diagnostics or non-camera
root causes, including but not limited to:
• Vehicle power / 12 V system concerns, including low battery state-of-charge and related DTCs (e.g., P0562, U3003-16).
• Serial data / CAN bus / Ethernet issues involving K56 Serial Data Gateway Module
and other ECUs (engine, transmission, EBCM, steering, radar sensors, etc.).
Cause

• Non-GM windshield glass or incorrect windshield installation (improper bracket alignment, incorrect glass, applied tints, or other alterations) affecting camera performance
and calibration.
• Improper B174W seating or bracket installation at the windshield.
• Software anomalies or calibration issues requiring reprogramming and the Front View
Camera – Windshield Learn procedure.
• Other ECUs setting U3000 or related DTCs where the root cause is not the front camera module.
As a result, replacing the B174W Front Camera Module without following the diagnostic
procedure often does not resolve the concern and contributes to unnecessary part usage.

Correction
Important: Do not replace the B174W Front View Camera Module for the conditions described above unless you
complete all of the steps in this procedure and PQC authorizes replacement.
Follow the steps in order. Document your answers in the RO.
Step A – Check communication with B174W Front View Camera module and the K56 Serial Data Gateway module.
Can your scan tool communicate with B174W Front View Camera module over Ethernet (wired connection)? (Yes/
No).
• If YES, go to Step B.
• If NO:
If using WiFi, try again using a wired connection to the vehicle network.
Note: It is strongly recommended to connect 'WIRED' from the PC to the MDI2 for this procedure. This procedure
involves transferring large amounts of data and needs a stable connection. Please switch to a "Wired' connection
prior to programming otherwise a programming failure might occur.
Note: It is strongly recommended that the SDGM is running the latest calibrations prior to attempting ACP2
programming.
Note: It is strongly recommended to use the latest MDI firmware version.
Note: It is strongly recommended NOT to use third party scan tools (i.e Topdon, Autel, CarDAQ, Mongoose)
Can you now communicate with B174W Front View Camera module? (Yes/No).

Bulletin No.: PIT6503C

August, 2026

Page 3

• If YES: go to Step B.
• If NO:
• This is most likely a scan tool or gateway communication issue, not a failed B174W Front View Camera module.
• Follow SI 5199686 and SI 5199685 to diagnose the scan tool and K56 Serial Data Gateway Module until you
can communicate with K56.
• If still no communication, use schematic SI 6539608 and SI 5969120 (DTC B1A1D) to diagnose the Ethernet
path between B174W and K56.
• If still no communication, try rerunning the SDAC procedure.
• Do not replace the front camera until this communication issue is resolved.
• Once connector has been reconnected and communication is restored, continue with Step B.
Step B - Is B1A05 (B174W Front View Camera module MCU_Missing Calibration) set as Active by B174W
Front View Camera module? (Yes/No).
• If YES:
• Follow SI 6656059 for this condition.
• If SI directs replacement of B174W Front View Camera module, then after replacement reprogram and perform
the Front View Camera – Windshield Learn procedure in SI 5969482, clear DTCs, and verify the concern.
• If the concern still exists, continue to Step C to perform CAN bus/gateway checks.
• If NO: continue.
Step C – CAN bus / gateway loss-of-communication checks. Are other ECUs setting U1615 (Lost Communication with B174W Front View Camera module on CAN Bus 2) as Active? (Yes/No).
• If YES:
• Check whether K56 Serial Data Gateway Module is also setting loss-of-communication DTCs against other
ECUs on CAN Bus 2 (for example U1611, U1643, U0131, U1610, U1615).
• If the entire bus is impacted (multiple ECUs with comm loss):
• Do not replace the B174W Front View Camera module.
• Diagnose the CAN Bus 2 issue using SI 5199680.
• If that SI leads to K56 or other module replacement, reprogram as required and then perform Front View
Camera – Windshield Learn (SI 5969482).
• If only B174W Front View Camera module is affected:
• Diagnose using SI 6535776 for U1615.
If NO: continue
Step D - U1616 (Lost Communication with B174W Front View Camera module on CAN Bus 8) set as Active?
(Yes/No).
• If YES:
• Check whether K56 Serial Data Gateway Module is also setting loss-of-communication DTCs against other
ECUs on CAN Bus 8 (for example U1126, U1127, U0235, U1616).
• If the entire bus is impacted:
• Do not replace the B174W Front View Camera module.
• Diagnose the CAN Bus 8 issue using SI 5199684.
• If a module is replaced, perform required programming and Front View Camera – Windshield Learn (SI
5969482).
• If only B174W Front View Camera module is affected:
• Diagnose using SI 6535777 for U1616.
• If NO: continue.
Have you completed all of the steps above in order? (Yes/No).
• If NO: go back and complete any missing steps.
• If YES:

Page 4

August, 2026

Bulletin No.: PIT6503C

• If the concern is resolved, no further action is required.
• If the concern is not resolved and an SI explicitly instructs replacing B174W Front View Camera Module, then:
Contact PQC to request authorization.
i. Provide:
• A summary of the customer concern and conditions.
• All recorded DTCs (Active and History, with FTB).
• The specific SI number and step that directs camera replacement.
• Confirmation that all steps in this procedure have been completed.
ii. Only after PQC approval, replace the camera with the correct restricted part number.
iii. After replacement, reprogram B174W Front View Camera module and perform the Front View Camera –
Windshield Learn procedure (SI 5969482), clear DTCs, and verify the concern is resolved.
Do not replace any of the above front camera modules solely based on DTC presence or driver messages
without following the full diagnostic procedure.
Note: If parts replacement is needed after following SI and the instructions in this PI, please provide the answers to
the attestation questions below when contacting PQC.
PQC Attestation Questions:
Q1. Is this part being requested for customer pay?
Q2. (Required) Provide the PIT6503 step number and/or SI Document ID and step number that directs camera
replacement
(Example: PIT6503 Step 2 or SI Doc ID 1234567 Step 3)
U.S Dealers:
Please contact the Product Quality Center (PQC) by opening a new PQC case via CX Connect in Global Connect.
Search for the associated PI/Bulletin number in CX Connect to download the appropriate PQC Parts Restrictions
Template and save a copy to your computer. Fill the form out and save it on your computer. You can then attach a
copy of the completed template to your PQC Case.
Canadian Dealers:
If your diagnosis leads to a possible part replacement, please contact the PQC by email at [email protected] or by
calling 1-866-654-7654 to receive the PQC -Parts Restriction Template. Once it has been filled out, return the
completed Parts Restriction Template for review.

Parts Information
Description

Part Number

Qty

86535062

Camera,
Forward View

1

85063357

Camera,
Forward View

1

85870485

Camera,
Forward View

1

85673847

Camera,
Forward View

1

Bulletin No.: PIT6503C

August, 2026

Page 5

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

6620110

Front View Camera
Replacement

Use
Published
Labor Time

2810835

Front View Camera
Reprogramming with SPS

Use
Published
Labor Time

6620295

Front View Camera Windshield Learn

Use
Published
Labor Time

2811325

B233B Forward Range
Radar Sensor - Long
Range Reprogramming
with SPS

Use
Published
Labor Time

2811345

B233LF Short Range
Radar Sensor - Left Front
Reprogramming with SPS

Use
Published
Labor Time

2811365

B233R Short Range Radar Use
Sensor - Rear
Published
Reprogramming with SPS Labor Time

2811375

B233RF Short Range
Use
Radar Sensor - Right Front Published
Reprogramming with SPS Labor Time

2811395

B233SL Short Range
Radar Rear Side Sensor Left Reprogramming with
SPS

Use
Published
Labor Time

2811405

B233SR Short Range
Radar Rear Side Sensor Right Reprogramming with
SPS

Use
Published
Labor Time

2811305

B218L Side Obstacle
Detection Control Module Left Reprogramming with
SPS

Use
Published
Labor Time

2811315

B218R Side Obstacle
Detection Control Module Right Reprogramming with
SPS

Use
Published
Labor Time

2810275

Serial Data Gateway
Module Reprogramming
with SPS

Use
Published
Labor Time

Version

4

Modified

04/14/2026 - Created on
05/26/2026 - Updated PQC attestation.
06/16/2026 - Updated vehicle list.
08/11/2026 - Updated Correction and Labor Operations.

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