DTC C2921 ID Registration Error and Bit Translation Table for Use in Tire Pressure Monitor System (TPMS) Diagnostics – 2017-2021 Subaru

NHTSA ID Number: 10182214

Manufacturer Communication Number: 05-78-20

Summary

This Service Information Bulletin announces additional diagnostic procedures for TPMS related DTC C2921 on the applicable models listed.

17 Affected Products

Vehicles

NUMBER: 05-78-20
DATE: 10/13/2020

INTRODUCTION:

This Service Information Bulletin announces additional diagnostic procedures for TPMS related DTC C2921 on the applicable models listed above.  In addition, a Bit Translation table for interpreting Tire Pressure Monitor System (TPMS) data and tire status will also be added to the Service Manuals for the models listed above.  A copy of the Bit Table is also included here.  DTC C2921 is detected when the ID registration has failed resulting in the TPMS warning light blinking 25 times, then staying illuminated.

SERVICE PROCEDURES / INFORMATION:

REMINDER:  Customer satisfaction and retention starts with performing quality repairs.

• The following C2921 Diagnostics Information will be added to the applicable Service Manuals soon.
• If the vehicle being repaired does not support DTC C2921, proceed to the Bit Translation table below.

DTC Detecting Condition:  When the ID registration is failed

Trouble Symptom:  Tire Pressure warning light blinks 25 times and then stays on

• Bit Translation Table Information: Use and Interpretation of Select Monitor Values

The Bit code is used to determine details of tire status and condition through an 8-digit binary TPMS status value on the SSM display, and is read Right to Left.  Each digit is associated with a Bit number of 7-0, with the Bit 7 being the left most digit, and Bit 0 being the right most as illustrated below.

CRITICAL REMINDER: Bit codes are to be read from Right to Left, with each Bit’s associated number going in descending order.  This means the far-left digit is Bit 7, while the last three digits to the right are Bits 2, 1 and 0  (referred to as Bit 2-0).

Bit Translation Table   NOTE: Bit 2-0 (Status Code) must be read as a group, NOT individually.  There are 7 conditions within Bit 2-0, therefore, an additional table explaining the binary combinations which could be seen on the SSM display is shown here and used to determine the condition.

Bit numbers:  7 6   5  4   3   2  1   0

TPMS status: 0 0 0 0 0 1 0 0

In the above example, the digits boxed in red are Bit 2-0.  Referencing the Bit 2-0 chart above right shows this combination (100) translates to Condition 4: Position detection in progress. The additional table below is provided to supplement the Service Manual information.

The Select Monitor screenshot below shows data for the TPM status for each wheel.  The four status lines in the red box are the Bit code values for each wheel.  According to the Service Procedure above, FL Tire Status and RL Tire Status have a “0” for Bit 4, which means ID registration can be attempted.  If they cannot be registered, those two TPMS sensors must be replaced.  Conversely, if Bit 4 stays at “1” after driving the vehicle for over 10 minutes, replace the indicated TPMS sensors and perform registration.  In the SSM4 window below, the FR Tire Status and RR Tire Status are both “1”.  If this is present after a test drive of at least 10 minutes, those TPMS sensors should be replaced for these wheels.

IMPORTANT REMINDERS:

• SOA strongly discourages the printing and/or local storage of service information as previously released information and electronic publications may be updated at any time.
• Always check for any open recalls or campaigns anytime a vehicle is in for servicing.
• Always refer to STIS for the latest service information before performing any repairs.

1 Associated Document

Manufacturer Communications

NUMBER: 05-78-20
DATE: 10/13/2020

https://www.nhtsa.gov/recalls?nhtsaId=10182214

MC-10182214-0001.pdf 1184.518KB

Loading...

Taking too long?

Reload document

| Open in new tab

Download [1.13 MB]

Bestseller No. 1

Autel TPMS Relearn Tool MaxiTPMS TS401, TPMS Reset, Sensor Activation, Program MX-Sensor, Key Fob Testing, Tire Pressure Monitor Sensor Reset Tool for GM, Ford and More Vehicle Brands

• 【Sensor Program】You have 3 multiple options to program the Autel sensor with this TPMS programming tool: Copy by Activation, Copy by Manual Input, and Auto Create. With Copy by Activation, the vehicle will automatically find the new sensor. Easy as Breeze.(Program function only support using in Autel sensors.)
• 【Sensor Relearn】This TPMS tire pressure relearn tool TS401 can do the Relearn procedure for 98% vehicle of market that comes into your auto repair shop in both 2 ways: Auto Relearn (which needs to test drive the vehicle) & Stationary Relearn (with the built-in relearn guide)
• 【Retrieve Infos】TS401 provides a TPMS tire pressure monitor system tool for you to capture sensor IDs, tire pressure, tire temperature, and check the sensor’s battery life & frequency. It is absolutely a time saver, and gives you the general area of where to start looking for a TPMS problem
• 【Lifelong Benefits】Autel TPMS sensor relearn tool TS401 can check your Key Fob’s frequency, saving you the hassle of running into a dealership. This price-point friendly TPMS tool also claims to have FREE lifetime update for the latest vehicles, with 12-month warranty provided

$135.00

Buy on Amazon Price incl. tax, excl. shipping

Bestseller No. 2

JDIAG EL50448 TPMS Reset Tool GM Tire Pressure Monitor Sensor Activation TPMS System Relearn Tool OEC-T5 for GM Series Vehicles

• 2020 Updated Version EL50448 is an essential tool of replacement tire pressure sensor, tire pressure alarm remove or exchange tires.
• Works on most General Motors (Chevy/Buick/GMC/Opel/Cadillac) equipped with Tire Pressure Monitor system (TPMS) sensor.
• Sensitive sensor, Circuit Optimal Design, Easy to use, Activates the individual TPMS sensor with the press of one button.
• Simple and inexpensive but works great. Much better than going to the dealer or a tire store just to get your pressure sensors reset.
• The upgraded EL50448 is more energy-saving. The indicator light will flash when the button is held down, and it won't flash when you release the button.Real-time Customer Service, please feel free to contact with Seller if with any questions(One year warranty).

$11.95

Buy on Amazon Price incl. tax, excl. shipping

SaleBestseller No. 3

VXDAS Auto Tire Pressure Monitor Sensor TPMS Relearn Reset Activation Tool OEC-T5 for GM Series Vehicle

• 【2020 For GM TIRE TPMS RELEARN TOOL】Works on most General Motors (Chevy / Buick / GMC / Opel /Cadillac etc)equipped with 315/433 MHz , Please check the last picture with exact car model. More car models will be updated after being tested!【Please comfirm VXDAS brand LOGO, without LOGO are FAKE, and not sure the quality】
• 【ESSENTIAL VEHICLE TOOL】Tire Reset Activate Easily within 1-2 Mins, after tire rotations or change a new tire, Remote Control Door Lock Receiver Module replacement or Tire Pressure Sensor replacement.
• 【EASY TO USE】tpms reset tool can help you reprogram all tires much easier just with 3 steps. Ensure that the vehicle is in the TPMS Learn Mode, and follow the service procedure. Hold tool against the sidewall of the tire, near the valve stem. Depress Learn button while holding the tool against the tire sidewall.
• 【SAVE TIME& MONEY】Tire pressure monitor sensor activation tool is simple and fast ,activates the individual TPM sensor with the press of one button easily within 1-2 Mins.Save your almost 20-80$,.Much better than going to the dealer or a tire store just to get your pressure sensors reset.
• 【FRIENDLY TIPS】[1].Different vehicle may need different times to reset all of your tire sensors after rotation,[2].take out battery if don't use,[3].Not for TRUCK & Please use NEW 9V battery(not include in package) 【Professional Support Ce and FCC approved. VXDAS provides 12 months warranty】

$10.99

Buy on Amazon Price incl. tax, excl. shipping

SaleBestseller No. 4

Arozk TPMS Relearn Tool for GM Tire Pressure Monitor System Sensor Programming Training Activation Tool OEC-T5 GL-50448 Auto Reset Tool for GM Series Vehicles 2006-2020

• 【2020 UPGRADED GL-50448】 This 2020 Upgraded TPMS Relearn Tool is Equipped with a round antenna and Switch button, offer a Faster & Stronger Signal than other TPMS Relearn Tool. Easy to operate with one hand.
• 【WIDELY VEHICLE SUITABLE】GL-50448 fits for General Motors (Chevy/Buick/GMC/Opel/Cadillac) which is equipped with 315 or 433 MHz Tire Pressure Monitor system (TPMS) sensor for 2006-2020.
• 【ESSENTIAL VEHICLE TOOL】Tire Reset Activate Easily within 1-2 Mins, after tire rotations or change a new tire, Remote Control Door Lock Receiver Module replacement or Tire Pressure Sensor replacement.
• 【EASY TPMS RESET】TPMS activation tool is easy to activate the individual TPMS sensor with the press of one button. Ensure the vehicle is in TPMS Learn Model, follow the User Manual, Hold tool against the sidewall of the tire, near the valve stem. Depress press button while holding the tool against the tire sidewall.
• 【FRIENDLY NOTES】1. 9V Battery should be in good condition. 2.Install/Reinstall the battery according to the "+" and "-" symbols marked on the product.3. Make sure the TPMS relearn tool is in correct position while using it. 4. GL-50448 has 12 months warranty. If any problem, just feel free to contact us for soon customer service.

$12.99

Buy on Amazon Price incl. tax, excl. shipping

Bestseller No. 5

Launch TPMS Relearn Activation Reset Tool for GM Tire Sensor Pressure Monitor System Programming Training Activation Tool Automotive OEC-T5 EL 50448 Vehicle Series 2006-2021

• 【GM TIRE PRESSURE RELEARN TOOL】For GM Vehicles (Chevy / Buick / GMC / Opel / Cadillac etc., from 2006-2019, Cars, SUV, Pickup) that is equipped with 315/433 MHZ tire pressure monitor system sensor. TPMS tire pressure sensor on models in & after 2012 can be read, only with some specified diagnostic tools.
• 【EASY TO USE】This EL-50448 OEC-T5 is simple, fast and easy to use, can help you reprogram all tire pressure easily within only 3 steps. Activates the individual TPMS sensors within 1-2 Mins by pressing one button.
• 【HOW TO Use】Make sure your car is in the TPMS Learning Mode , Hold the tool against the sidewall of the tire, near the valve stem. Depress learn button while holding the tool against the tire sidewall until horn bleeps once.
• 【ESSENTIAL TRIANING TOOL】EL-50448 OEC-T5 is a essential tool of replacement tire pressure sensor, tire pressure alarm remove or exchange tires. Perfect to monitor tire pressure, training sensors of your cars so the TPMS warning light will not illuminate.
• 【WARM TIPS】1. Please check the available vehicles in the last two pictures, and this tool is not for TRUCK; 2. When using EL-50448, please make sure antenna in correct position; 3. Battery is not included in the package, please remove the 9V battery when not in use. 4. Install/Reinstall the battery according to the "+" and "-" symbols marked on the product.

$10.99

Buy on Amazon Price incl. tax, excl. shipping

Bestseller No. 6

JDIAG 2IN1 TPMS Relearn Tool Super EL50448 for GM and Ford Tire Pressure Monitor Sensor TPMS Reset Tool 2021 Edition

• 2-in-1 TPMS Tool: Super EL50448 works as both EL-50448 GM series and EL-50449 Ford Series TPMS19 tire sensor reset tool.
• Wide Vehicle Coverage: tps relearn tool work on most General Motors /Ford/Buick/Cadillac/Chevy/GMC/Lincoln/Mercury equipped tpms tire pressure monitor system can be reset, up to year 2021.
• One Button Design: Super EL-50448 TPMS relearn tool protected by rubber cover, with ease, faster operation, reset the individual TPMS sensors by pressing one button.
• An essential tool of replacement tire pressure sensor, tire pressure alarm remove or exchange summer and winter tires.Much better than going to the dealer or a tire store to get your tire sensors reset.
• Note: TPMS tool works normally if can reset one sensor successful, the issue will be considered: other sensors defective/battery low/blank sensor/frequency not the same;...9V battery not included;

$17.95

Buy on Amazon Price incl. tax, excl. shipping

Bestseller No. 7

VXSCAN 3 in 1 Tire Reset Tool, TPMS Relearn Activation Tool Auto Tire Pressure Monitor Sensor for TOYATA/GM/Ford 2020 Edition

• 【Enhanced Suitable Scope for Vehicles】TOYATA/GM/FORD with the tire pressure sensor models do not support the manual reset, need to use tire pressure reset device for tire pressure reset operation. So we have enhanced product performance, expanded the product adaptation range, and made the product more usable high.
• 【Only 3 steps】VXSCAN TPMS reset tool can help you reprogram all tires easier with 3 steps.Not for TRUCK & Please use NEW 9V battery.
• 【Precautions for use】Ensure that the vehicle is in the TPMS Learn Mode, and follow the service procedure. Hold tool against the sidewall of the tire, near the valve stem. Depress Learn button while holding the tool against the tire sidewall.
• 【Just one button】Simple, Fast and Easy to Use,Tester activates the individual VXSCAN 3 in 1 Tire Pressure sensor with the press of one button.
• 【Note】Please read the PDF file in the Technical Specification carefully, and inquire about VXSCAN VXSCAN 3 in 1 Tire Pressure TPMS suitable models. If you inadvertently find that new models is also available, please contact us in time to add. Any technical issues will be resolved within 24 hours.

$35.99

Buy on Amazon Price incl. tax, excl. shipping

Bestseller No. 8

FASLINK TPMS Relearn Tool for GM Jeep and Ford Series Vehicle U508 Universal Tire Pressure Monitor Sensor TPMS Reset Tool 2020 Edition

• PERFECT AUTOMOTIVE TIRE PRESSURE MONITOR SENSOR：you can be activated by Done alone within 3—5 minutes. Save time and money , much better than going to a dealer or tire storage just to reset the pressure sensor.
• WIDE VEHICLE COVERAGE: Works on most vehicles equipped TPMS system, Please check the last picture with exact car model list to check whether your car compatible with U508 tpms tool, more models will be updated in future after being tested!
• TPMS RESET TOOL：U508 is a essential tool with a 315MHz or 433 MHz tire pressure monitoring system,of replacement tire pressure sensor, tire pressure alarm remove or exchange tires.
• ONLY 3 STEPS：1.Make sure your car is in the TPMS Learning Mode , 2.Hold the tool against the sidewall of the tire, near the valve stem. 3.Depress learn button while holding the tool against the tire sidewall until horn bleeps once.
• FRIENDLY TIPS：[1] When using U508 tpms relearn tool, please make sure antenna in correct position; [2] Not for heavy trucks with more than 4 tires & Please use NEW 9V battery (not include in package) 【 Provides 24 months warranty, relieve all your worries.】

$39.85

Buy on Amazon Price incl. tax, excl. shipping

Bestseller No. 9

GUTA Tire Pressure Monitoring System - 4 External Sensor(0-188 PSI) tpms, 6 Alarm Modes, High-end Backlight LCD Display, Automatic Sleep Mode, Can Monitor up to 8-10 Tires, Real-time Monitor Pressure

• [Longer Acceptance Distance - Can Monitor Up to 8-10 Tires] GUTA RV tire pressure monitoring system is equipped with high-end external sensors. Long monitoring sensing distance up to 36 feet make the TPMS adapted to different vehicles. The TPMS can monitor the real-time tire pressure of 8 main tires and 2 spare tires at the most to protect your driving safety. Note: The package does not include the booster.
• [2 Way Charging - Solar Power & USB Charging] GUTA tire pressure monitoring system supports USB cable charging & solar charging. It can be fast-charged without occupying the car cigarette lighter socket and manual charging, to ensure the tire pressure monitoring system could work continuously.
• [6 Alarm Modes - Guard Your Driving Safety] GUTA tire pressure monitoring system has 5 alarm modes to remind you of the abnormal situation with visible and audible alert (LED flash light and warming beep), including fast leak alarm, high/low-pressure alarm (you would set high/low-pressure alarm thresholds by axle), high-temperature alarm, sensor low voltage alarm, and sensor data loss alarm, ensuring your driving safety.
• [Big LCD Screen Auto Backlight - Easy Reading Under Any Light Environment] GUTA RV tpms supports smart backlighting. High-end HD LCD display with 2 lighting level, would adjust the brightness automatically, which help to read the data clearly. The TPMS display could show 8 tires at a time (monitor up to 10 tires, including 2 spare tires) and the content contains the temperature (℉/℃) and pressure (PSI/BAR
• [Power Saving Mode - Less Worry and More Durable] The TPMS display will automatically enter the power-saving mode after 10 minutes parking or when the monitor power is low. Tire pressure will be continuously transferred to the monitor under sleep mode. Press any key or start the car to awaken the monitor, feel free to check for the real time tire data while the car is stationary. For the vehicle using with the booster, starting the car allows the monitor to receive the back tire data.

$143.99

Buy on Amazon Price incl. tax, excl. shipping

Bestseller No. 10

VXDAS TPMS Relearn Tool for GM Jeep Ford Toyota Nissan/Honda/Mazda/BMW Series Vehicles Ultimate EL-50448 Universal Tire Pressure Monitor Sensor TPMS Reset Activation Tool 2020 Edition

• WIDE VEHICLE COVERAGE: Ultimate EL50448 Works on most vehicles equipped TPMS system。supports GM,Ford ,BMW/Audi/Renault/Toyota/Nissan/Honda/Mazda/Mitsubishi//Subaru till Dec 2020 cars.more models will be updated in future after being tested on the late pictures!
• AFFORDABLE RELEARNING TOOLS: It’ a perfect tool that can detect and relearn (find) the location of sensors in case of a tire change ,rotation or sensor replacement o . It will save you many trips to the tire shop because it’s simple to use.
• WIFI BUTTON: It has two WiFi buttons but they do not offer internet capability. They’re just to turn the device on and off. This way your 9v battery can run for a longer period.
• ONLY 3 STEPS：1.Make sure your car is in the TPMS Learning Mode , 2.Hold the tool against the sidewall of the tire, near the valve stem. 3.Depress learn button while holding the tool against the tire sidewall until horn bleeps once.(Notice:Press “off “WiFi buttons after completing a tire reset.Then once again to start another tire)
• FRIENDLY TIPS：[1] When using Ultimate EL50448 tpms relearn tool, please make sure antenna in correct position; [2] Not for heavy trucks with more than 4 tires & Please use NEW 9V battery (not include in package) 【 Provides 24 months warranty, relieve all your worries.】

$32.99

Buy on Amazon Price incl. tax, excl. shipping

Last update on 2021-01-25 / Affiliate links / Images from Amazon Product Advertising API