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
| MAKE | MODEL | YEAR |
| SUBARU | ASCENT | 2019-2021 |
| SUBARU | CROSSTREK | 2018-2020 |
| SUBARU | FORESTER | 2019-2021 |
| SUBARU | IMPREZA | 2017-2021 |
| SUBARU | LEGACY | 2018-2020 |
NUMBER: 05-78-20
DATE: 10/13/2020
| DTC APPLICABILITY: | 20MY Legacy & Outback 2020-21MY Forester 2020-21MY Impreza 2020-21MY Crosstrek |
| BIT TABLE APPLICABILITY: | 2018-19MY Legacy & Outback 2019MY Forester 2017-19MY Impreza 2018-19MY Crosstrek 2019-21MY Ascent |
| SUBJECT: | DTC C2921 ID Registration Error and Bit Translation Table for Use in Tire Pressure Monitor System (TPMS) Diagnostics |
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
| STEP | CHECK | YES | NO |
| 1. CHECK DTC. Read the DTC of «Tire Pressure Monitor» using the Subaru Select Monitor. | Is a DTC other than DTC C2921 displayed as current or past malfunction? | Perform the diagnosis for the displayed DTCs. If the past malfunction C2121-C2124 is displayed, perform the diagnosis from the Step 2 of the DTC C2121-C2124. | Go to Step 2. |
| 2.REPRODUCTION OF FAILURE. 1) Perform the drive test. Drive the vehicle at 40 km/h (25 MPH) or faster for at least 10 minutes until the Bit 4 (PAL Condition) of the Tire Status becomes “0”. 2) Read the DTC of «Tire Pressure Monitor» using the Subaru Select Monitor. | Is DTC displayed as current malfunction? | Go to Step 3. | When DTC is displayed as “Past faults”, it means that the system has returned to normal. NOTE: In this case, conditions such as electromagnetic interference for which ID registration is difficult are assumed. |
| 3. ID REGISTRATION. Register the ID. | Can the ID be registered? | Go to Step 2. | Replace the TPMS. |
- 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 | Data | Condition |
| 7 | Low Battery | Indicates remaining battery |
| 6 | Sensor Fail | Indicates malfunction of TPMS |
| 5 | LF Response | Indicates response transmission to LF signal |
| 4 | PAL Condition | Indicates positioning information status |
| 3 | Rolling Detection | Indicates statuses of tire rotation detection |
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
| 2-0 (2,1,0) | Status Code | Indicates status at valve transmission | 0: Responded to LF signal “Learn LF” 1: Tire pressure change detected |
| 1: Tire pressure change detected | |||
| 2: — | |||
| 3: LF signal “Entering off LF” responded | |||
| 4: Position detection in progress | |||
| 5: Position detection in progress (transmission timing asynchronized with tire rotation | |||
| 6: Normal driving (when position detection mode completed) | |||
| 7: End of tire pressure change detected |
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.
| Status Code in SSM (Binary Bit code 2-0) | Condition Number (Decimal) | Condition |
| 111 | 7 | End of tire pressure change detected |
| 110 | 6 | Normal driving (when position detection mode) |
| 101 | 5 | Position detection in progress (transmission timing asynchronized with tire rotation) |
| 100 | 4 | Position detection in progress |
| 011 | 3 | LF signal “Entering off LF” responded |
| 010 | 2 | —– |
| 001 | 1 | Tire pressure change detected |
| 000 | 0 | Responded to LF signal “Learn LF” 1:Tire pressure change detected |
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
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Bestseller No. 1 
VXDAS TPMS Relearn Tool for GM Tire Sensor TPMS Reset Tool Tire Pressure Monitor System Activation Tool OEC-T5 for GM Buick/Chevy/Cadillac Series Vehicles 2021 Edition
- 【2021 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】
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Arozk TPMS Relearn 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 2006-2021, 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.
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JDIAG EL-50448 TPMS Relearn Tool for GM Auto Tire Pressure Monitor System Sensor Activation TPMS Reset Tool OEC-T5 for GM/Buick/Chevy/Cadillac Series Vehicles 2021 Edition
- 【2021 Updated EL50448】EL50448 TPMS relearn tool is an essential tool of replacement tire pressure sensor, tire pressure alarm remove or exchange tires. The upgraded EL50448 is more energy-saving, it is faster, stronger and more sensitive than other TPMS Relearn Tool.
- 【WIDE VEHICLE COVERAGE】Works on most GM Vehicles (Chevy / Buick / GMC / Opel / Cadillac etc., from 2006-2021, Cars, SUV, Pickup) equipped with 315 or 433 MHz Tire Pressure Monitor system (TPMS) sensor.
- 【EASY To USE】EL50448 can help you reset 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. When using EL50448, please make sure antenna in correct position. 2. Please make sure the 9v battery in good condition. 3.For Different vehicle EL50448 may need different times to reset all of your tire sensors after rotation. 4. 12 months guarantee, please feel free to contact us if you have any trouble during use.
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VXSCAN TPMS Relearn Tool El50448 Auto Tire Pressure Monitor Sensor Reset OEC-T5 for GM Series Vehicle
- 【TPMS RESET TOOL】VXSCAN TPMS Relearn Tool is a essential tool with tire pressure monitoring system, it can make tire pressure matching with vehicles when replacement tire pressure sensor, tire pressure alarm remove or exchange tires.Bring you safety and security.
- 【ACTIVATE TPMS】When you inflate the tires of the vehicle, your tire pressure parameters will change, and the vehicle will prompt that TPMS needs to be activated. At this time, you can use the VXSCAN TPMS relearn reset tool to activate and troubleshoot to ensure the normal operation of the vehicle.
- 【EASY-TO-USE TIRE PRESSURE MONITOR SENSOR】You can finish activated independently within 3—5 minutes. Save your time and money , much better than going to a dealer or tire storage just to reset the pressure sensor.
- 【SUITABLE SCOPE FOR VEHICLES】 Please check your car model whether it can work with VXSCAN tool in the fourth picture.We have listed a chat about the Suitable Scope for Vehicles. TPMS tire pressure sensor on models in & after 2012 can be read, only with some specified diagnostic tools.
- 【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. We promise to provide you with 24-hour customer service and the 3-5 years warranty.
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VXDAS TPMS Relearn Tool for GM Jeep F150 Toyota Nissan/Honda/Mazda/BMW Series Vehicles Ultimate EL-50448 Universal Tire Pressure Monitor Sensor TPMS Reset Activation Tool 2021 Edition
- WIDE VEHICLE COVERAGE: Ultimate EL50448 Works on most vehicles equipped TPMS system.supports GM,F150 ,BMW/Audi/Renault/Toyota/Nissan/Honda/Mazda/Mitsubishi//Subaru till Dec 2021 cars.more models will be updated in future after being tested on the late pictures!
- TPMS 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.】
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Greyghost TPMS Relearn Tool for GM, EL-50448 Orange TPMS Reset Tool Tire Sensor Tire Pressure Monitor System Activation Tool, OEC-T5 for GM Series Vehicles 2006-2021
- 【2021 EL-50448 TPMS Relearn Tool】: For GM series vehicles equipped with a 315MHz or 433 MHz tire pressure monitoring system, a "sensor relearn procedure" must be performed after tire rotations, remote control door lock receiver module replacement or tire pressure sensor replacement. This relearn procedure can be performed by using special tool EL-50448.
- 【GM TPMS Reset Tool】: EL-50448 Orange OEC-T5 can help you reprogram your tire pressure easily within just 3 steps. This TPM relearn reset tool is easy to activate the individual TPM sensor with only pressing one button.
- 【TPMS Sensor Activation Tool】: EL-50448 works on all General Motors products (Buick, Cadillac, GMC) that have TPMS sensors. Please check whether EL-50448 is available for your car, see the last picture.
- 【Easy To Use】: Before using this TMS relearn tool & TPS reset tool, make sure your car is in the TPMS learn mode. Hold the tool against the sidewall of the tire, near the valve core. Press learn button while holding the tool against the tire sidewall until hearing horn sound from the car.
- 【Notice】: Different vehicles may need different times to reset all of your tire sensors after rotation. 12 months guarantee, please feel free to contact us if you have any trouble during use.
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VXDAS GL50448 TPMS Relearn Tool Compatible with GM Chevy Tire Pressure Sensor Reset Activation Tool OEC-T5 for GM/Buick/Chevrolet/Cadillac/Nissan/Series Vehicles 2021 Edition
- 【2021 Updated GL-50448】Equipped with a round antenna and Switch button,let Open Signal Faster and Stronger than other TPMS Relearn Tool.also More sensitive and Suitable for your fingers operation.
- WIDE VEHICLE COVERAGE】VXDAS GL-50448 works on GM (Chevy/Buick/GMC/Opel/Cadillac) equipped with Tire Pressure Monitor system (TPMS) sensor
- 【Save Time& Money】Save your almost 20-80$ and time to tire shop,Activate Easily within 1-2 Mins.when replacement tire pressure sensor, tire pressure alarm remove or exchange tires.
- 【EASY To USE】Sensitive sensor, Circuit Optimal Design, Easy to use, Activates the individual TPMS sensor with the press of one button.Ensure that the vehicle is in the relearn mode, and following the service procedure. Hold tool against the sidewall of the tire, near the valve stem. Depress press button while holding the tool against the tire sidewall.
- 【FRIENDLY TIPS】1. When using tpms relearn tool , please make sure antenna in correct position 2.And 9V battery should be in good condition,3.When activation of a tire is finished,sometimes the horn or flashing will feedback.
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Arozk TPMS Relearn Reset Tire Pressure Monitor Sensor Program Train Tool Replacement for F150 Cars Escape Focus Mustang Expedition Explorer Lincoln Navigator Mercury Monterey Mariner Replace TPMS19
- 【REPALCEMENT FOR F150 SERIES VEHICLES】This TPMS Sensor Training Tool is compatible with f150 cars Lincoln Mer-cury, Maz-da vehicles that has a Tire Pressure Sensor. Training the TPMS sensors and activate TPMS on new vehicles or after a tire rotation.
- 【REPLACEMENT FOR P/N】8C2Z-1A203-A,8C2Z1A203A,8C2T-1A203-AB,8C2Z1A203AB,TPMS19
- 【ESSENTIAL TRIANING TOOL】TPMS19 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
- 【EASY TO USE】Super mini TPMS activation tool with ease, faster operation, activates the individual TPMS sensors by pressing one button, Easy installation
- 【PREMIUM QUALITY】 Made of High-quality material for long-lasting durability, battery life up to 5 years with normal use. Professional Support CE and FCC approved and 12 months warranty.
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Arozk TPMS Sensor Relearn Reset Tool for Ford and Mazda Tire Pressure Monitor System Sensor Programming Training Activation Tool TPMS Trigger Tool Motorcraft TPMS19 Transmitter
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- 【REPLACEMENT FOR P/N】8C2Z-1A203-A,8C2Z1A203A,8C2T-1A203-AB,8C2Z1A203AB,TPMS19
- 【ESSENTIAL TRIANING TOOL】TPMS19 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
- 【EASY TO USE】Super mini TPMS activation tool with ease, faster operation, activates the individual TPMS sensors by pressing one button, Easy installation
- 【PREMIUM QUALITY】 Made of High-quality material for long-lasting durability, battery life up to 5 years with normal use. Professional Support CE and FCC approved and 12 months warranty.
Bestseller No. 10 
JDIAG TPMS Relearn Tool Super EL50448 2 in 1 Tire Pressure Monitor System Sensor Reset Support Vehicles from 2005 to Present
- 【 Wide Vehicle Coverage 】Works on most vehicles equipped with 315/433MHz tire sensor.【Not for Heavy TRUCK & Please use NEW 9V battery(not included in package)】
- 【 Save Money & Time 】Super EL50448 TPMS Relearn Tool is simple and fast ,activates the individual TPMS sensor with the press of one button easily within 1Mins. Reset the tire pressure sensor by yourself and save you $50-100 each time.
- 【 When is it needed? 】After replacing car tires, after repairing tires, after replacing tire pressure sensors, and after replacing winter/summer tires, you need to use the tire pressure sensor reset tool.
- 【 Easy to use 】TPMS reset tool can help you reset 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.
- 【 Note 】 The TPMS tool is unable to reprogram sensors, Please use other tool program sensors first if necessary, then use our Super EL50448 to relearn the sensors. 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;
Last update on 2021-09-15 / Affiliate links / Images from Amazon Product Advertising API
Last update on 2021-09-15 / Affiliate links / Images from Amazon Product Advertising API
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