Chevrolet Bolt EV / EUV Fault Codes
Documented GM-specific diagnostic codes for the 2017-2023 Chevrolet Bolt EV and 2022-2023 Bolt EUV. Every code on this page traces to a published GM service bulletin or NHTSA TSB. Bolt owners became deeply familiar with these codes through the 2021 LG cell battery recall (NHTSA 21V-560), and many codes documented here are the ones that triggered or followed that recall. Generic OBD-II readers won't display these GM codes. You need a scan tool with GM module support (Tech 2, GDS2, Autel, or Foxwell with GM software).
Documented Bolt EV Fault Codes
Showing all 12 codes, sorted by severity. Each links to causes, diagnostics, and the GM TSB or NHTSA bulletin it comes from.
GM Code Range Reference
| Range | Subsystem | What it covers |
|---|---|---|
| P0Axx | Hybrid/EV Battery System | High-voltage battery voltage, isolation, sensor circuit, and disconnect relay faults. P0AFA, P0ABB, P0ABC, P0AA1. |
| P0Bxx | Battery Pack Cell Variation | Cell voltage delta, pack imbalance. P0BBD is the famous code from the 2021 LG cell recall. |
| P0Cxx / P0Dxx | Battery Charger / Precharge | Battery system precharge timing, manual service disconnect fuse faults. P0C78, P0D26. |
| P1xxx | GM Manufacturer-Specific | HPCM2 internal codes, propulsion module faults. P1AE6 isolation sensor, P1B03 propulsion loss, P1E00 MIL request. |
| U3xxx | High Voltage Diagnostic Range | GM-defined HV diagnostic codes U3620-U362E and U3630-U3636. Symptom byte determines whether the code is hardware (17) or a software glitch (09). |
Key TSBs & Recalls
The Bolt EV has more publicly-documented service bulletins than most EVs because of the LG cell recall. These TSBs are the source of every code on this page.
- 18-NA-225 — No-propulsion / loss of propulsion involving the high-voltage manual service disconnect fuse. Covers P0AFA, P0ABB, P0ABC, P0C78, P0D26, P1AE6.
- 19-NA-220 — Sudden loss of propulsion from a spread terminal in transmission harness connector X2. Covers P0A3F + P1B03.
- 21V-560 / 21277 (Recall) — LG cell defect battery recall on 2017-2022 Bolt EV and 2022 EUV. Affected cars received pack replacement; some pack-related codes were resolved by the recall.
- 22-NA-151 — Battery pack voltage variation diagnostics. Covers P0BBD interpretation and required cell-level inspection.
- 23-NA-157 / N232421260 — High-voltage system fault U3620 and related codes. HPCM2 reprogramming for software over-sensitivity (symptom byte 09 false DTC).
- N242437530 / N242443490 — Updated HPCM2 calibration to address persistent U3620-U362E and U3630-U3636 false-DTC complaints in the field.
- N232421261 — U3636 specific service update with symptom byte 09 false DTC handling.
How to Read Bolt EV Codes
Dealer Scan Tool
Tech 2 or Global Diagnostic System (GDS2) is the only tool with full BECM and HPCM2 module access. Required to read symptom bytes (e.g., U3620 byte 09 vs. byte 17). Available at Chevy dealers and many independent EV shops.
Aftermarket Scanners
Autel MaxiSys (MS906BT and up), Foxwell NT530 with the GM software pack, or Launch X431 read most P0Axx, P0Bxx, and U3xxx codes. Mid-range Bolt-capable scanners run $300-700.
Generic OBD-II
Cheap Bluetooth dongles (BlueDriver, OBDLink MX+) only display generic powertrain codes. They will NOT show the GM-specific P0Axx or U3xxx ranges that matter for Bolt diagnostics. Worth knowing before you buy a $30 reader expecting full visibility.