If you search for "VW ID.4 battery SOH OBD," every guide talks to the BMS over 29-bit CAN. We found that the MEB gateway also routes 11-bit CAN — with ECUs that nobody had documented, including one that reports usable battery capacity.
VW MEB cars (ID.3, ID.4, ID.5, Q4 e-tron, Enyaq, Born) use 29-bit extended CAN addressing for most diagnostic communication. Every OBD guide tells you to use ATSP7 (29-bit, 500kbps) and address the BMS at FC007B. This works perfectly for cell voltages, temperatures, SOC, current, and charge limits.
We also found usable battery capacity on a different ECU: PowerDist (ECU 710) — which speaks a different protocol entirely.
After two sessions of "ECU 710 is unreachable," we tried switching from 29-bit to 11-bit CAN:
ATZ ATSP6 ← 11-bit CAN instead of ATSP7 (29-bit) ATSH 710 ← PowerDist ECU ATCRA 77A ← Response address ATFCSH 710 ← Flow control ATFCSD 300000 ATFCSM1 1003 ← Extended diagnostic session 22 2AB2 ← Read usable capacity
Response: 62 2A B2 05 91 04 00
First two data bytes: 05 91 = 1425. Formula: raw × 50 / 1000 = 71.25 kWh.
Nominal usable capacity for the 82 kWh LG pack is 77 kWh. SOH = 71.25 / 77 = 92.5%.
The MEB OBD gateway routes two different CAN protocols through the same OBD-II port. BMS and Gateway use 29-bit (ATSP7). PowerDist, OBC, and other ECUs use 11-bit (ATSP6). Most OBD guides and forum posts for MEB only cover the 29-bit protocol — the 11-bit ECUs are rarely documented.
Once we could talk to ECU 710, we found much more than SOH:
| DID | Signal | Value |
|---|---|---|
| 2AB2 | Usable capacity (SOH) | 71.25 kWh |
| 2AB4 | Range estimate | 345 km |
| 2AB6 | Range displayed | 215 miles |
| 2AF7 | 12V battery (11 signals) | 14.8V, 84% SOC, 94 Ah |
| 15D1 | Charge mode | 1=parked, 4=charging |
| 2A53 | DC-DC converter | 14.9V output |
We've found 8 ECUs accessible through the OBD port on a 2021 ID.4. Other MEB variants may have more:
| Protocol | ECU | Address | Key Data |
|---|---|---|---|
| ATSP7 (29-bit) | BMS | 007B | 96 cells, 24 temps, SOC, current |
| ATSP7 | Gateway | 0076 | Odometer, VIN, torque, gear |
| ATSP7 | Motor | 0001 | Motor data |
| ATSP7 | DC-DC | 00B9 | 12V converter |
| ATSP6 (11-bit) | PowerDist | 710 | SOH, range, 12V health |
| ATSP6 | OBC | 744 | Charging duration, energy |
| ATSP6 | VCMS | 746 | Not yet decoded |
| ATSP6 | HV Power | 74A | Not yet decoded |
Our reading of 92.5% SOH at 39,500 km on a 2021 ID.4 Pro S matches community data. The vwidtalk SOH tracking spreadsheet (~375 data points from ~169 owners at the time of writing) shows LG packs at 20-30K miles averaging 93.1% SOH. Our car is slightly below median — normal for 4+ years in a New England climate.
All you need is a BLE OBD-II adapter (we've tested vLinker MC+ and VEEPEAK BLE+) and an iPhone. CellPulse is a free app that reads SOH, all 96 cell voltages, 24 temperature sensors, and produces a shareable PDF report. Currently in TestFlight beta.
Should work on all VW Group MEB vehicles: ID.3, ID.4, ID.5, ID.Buzz, Audi Q4 e-tron, Skoda Enyaq, and CUPRA Born.
We're working on trend tracking (scan the same car over months and watch SOH change) and percentile scoring ("your battery is better than 87% of similar cars"). The scoring methodology and privacy policy are fully transparent.
If you have an MEB vehicle and want to check your battery health, join the beta. Every scan helps build the reference dataset for better scoring.