Service Bulletin

21-027

August 31, 2021

Version 1

ACC Warning Lamp Is On With DTC P2583-76 In Low/Near Freezing
Ambient Temperatures
AFFECTED VEHICLES
Year

Model

Trim Level

VIN Range

2019-20

RDX

ALL

ALL

2021

RDX

2WD

5J8TC1…ML000001 thru 5J8TC1…ML010642

SH-AWD

5J8TC2…ML000001 thru 5J8TC2…ML021431

SYMPTOM
The ACC system error message comes on while driving when outside temperatures are low/near freezing.
POSSIBLE CAUSE
Snow and ice stuck to the front of the millimeter wave radar can cause DTC P2583-76 (Temporary stop of Integrated Driver
Support System [Misalignment Millimeter Wave Radar]) to be stored.
CORRECTIVE ACTION
After the inspection procedure, update the millimeter wave radar software if needed.
WARRANTY CLAIM INFORMATION
The normal warranty applies.
Operation
Number
7805J1
7385A2

Description

Flat Rate
Time

Diagnose and inspect
millimeter wave radar.
Includes DTC clear.

0.3 hr

Update the millimeter
wave radar software.

0.2 hr

Defect
Code

Symptom
Code

Template
ID

Failed Part Number

03214

03217

B21027A

36803-TJB-A03

Skill Level: Repair Technician

CLIENT INFORMATION: The information in this bulletin is intended for use only by skilled technicians who have the proper tools, equipment, and
training to correctly and safely maintain your vehicle. These procedures should not be attempted by “do-it-yourselfers,” and you should not assume this
bulletin applies to your vehicle, or that your vehicle has the condition described. To determine whether this information applies, contact an authorized
Acura automobile dealer.
© 2021 American Honda Motor Co., Inc. – All Rights Reserved

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INSPECTION PROCEDURE





Connect the i-HDS and check whether DTC P2583-76 (Temporary Stop of Integrated Driver Support System
[Misalignment Millimeter Wave Radar]) is stored.
Inspect the millimeter wave radar and the mounting bracket, and confirm that they are not deformed or damaged.
Ask the customer questions to confirm whether there was a possibility of snow/ice being stuck to the front of the radar
when the symptom occurred. Was it snowing or was the temperature below freezing?
If you confirm the above content and can judge that the symptom occurred due to snow/ice sticking to the radar,
proceed with the repair procedure below, and have the Service Advisor provide an explanation to the customer.
For more information see Service News article B21070A, ACC Warning Message Comes Back On After S/B 21-027.
NOTE: If none of the above applies, then continue with normal troubleshooting.

SOFTWARE INFORMATION
NOTE: Unnecessary or incorrect repairs resulting from a failure to update the diagnostic and reprogramming software are
not covered under warranty.
Before beginning the repair, make sure all diagnostic and reprogramming software are updated as listed.
i-HDS Software Version

1.006.035

HDS Software Version

3.104.040

J2534 Rewrite Software Information
PC Application Version

1.2.1.1

Database Update

05-AUG-2021

NoticeDB Version

05-AUG-2021

Update only the systems and software listed in this service bulletin.
American Honda has validated and approved the Denso DST-I as the vehicle communication interface (VCI) to
support this service bulletin.
For more information about updating vehicle systems, refer to service bulletin 01-023, Updating Control Units/Modules.
Year/Trim Level

Vehicle System

Program ID (or later)

2019–21 RDX (ALL)

Millimeter Wave Radar

36802-TJB-A050

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REPAIR PROCEDURE
NOTE:
 Make sure the 12-volt battery is fully charged before starting an update.
 Connect a fully charged jumper battery to the vehicle, and leave it connected during the entire procedure to
maintain steady voltage.
 Do not use the GR8 because the vehicle requires a steady electrical current.
 Control module failure caused by the improper completion of a software update (early key cycle, low battery
voltage, disconnected DLC cable, etc.) is not covered by warranty.
 If an error occurs during the update or the i-HDS freezes, do not disconnect the battery or turn the ignition
to OFF. Reboot the i-HDS, and start over.
 To prevent control unit damage, do not operate anything electrical (headlights, audio system, brakes, A/C, power
windows, door locks, etc.) during the update.
 Warranty reimbursement for technician labor is not allowed for routine checking/installation of any available
software update.
Update the millimeter wave radar software using the J2534 Rewrite software with the DST-i. Refer to service
bulletin 01-023, Updating Control Units/Modules.
NOTE:




If an updated vehicle returns with the Adaptive Cruise Control System Problem message on and snow/ice is
suspected, confirm the radar surface is clean, then road-test the vehicle or perform the millimeter wave radar
aiming procedure.
The DTC cannot be deleted by the i-HDS until the radar is re-calibrated by driving the vehicle.
If the Adaptive Cruise Control System Problem message disappears by driving the vehicle, then it is not
necessary to do the millimeter wave radar aiming procedure.

END

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