U029A code meaning
Lost Communication With Hybrid/EV Battery Pack Sensor Module
What U029A means
The battery pack sensor module is the electronics inside the high-voltage battery that reports pack current and voltage; many designs house it together with the main contactors. U029A means the battery or vehicle controller no longer hears from it. Stellantis documents the code in the battery pack control module of the 2024 Dodge Charger with 400 V electric drive: bulletins 08-026-25 Rev. B and 08-126-25 Rev. B reflash several modules and, if U029A stays, call for a six-minute sleep with the scan tool unplugged before a BPCM soft reset. Audi files U029A00 under address 8C for the 2025 Q5 e and the 2024 Q8 Sportback e-tron. Ford's 2014 code list shows it without the lamp flag. Lacking these values, the car may refuse to drive or charge.
U029A at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U029A
- Wrench or turtle symbol, reduced power
- Vehicle does not enable drive or stops charging
- High-voltage system warning in the cluster
Common causes of U029A
- Most likelyOutdated software in the battery control module or sensor module
- PossibleCode latched after programming because the network never went to sleep
- PossibleMoisture or poor contact at the battery low-voltage connector or bus wiring
- Less likelyBattery pack sensor module internally failed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery sensor moduleVehicle bus wiring
What each part of U029A means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 9A | The exact fault in that area. |
What to do next
- Note U029A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U029A
What does U029A mean?
U029A means "Lost Communication With Hybrid/EV Battery Pack Sensor Module". The battery pack sensor module is the electronics inside the high-voltage battery that reports pack current and voltage; many designs house it together with the main contactors. It is a generic code, so it means the same on every make.
Is it safe to drive with U029A?
Drive gently and only to a workshop. With U029A the car can go into limp mode (reduced power) to protect itself.
Will U029A fail an emissions test?
U029A is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U029A to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U029A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.