OBD Guide
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U01A9

Lost Communication With Hybrid/EV Battery Interface Control Module J

U01A9 is an OBD-II diagnostic trouble code meaning: Lost Communication With Hybrid/EV Battery Interface Control Module J. Common causes: open or short circuit in the can bus, problems with power supply to the battery management module. Estimated repair cost: $167–556.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$167–556 (est.)

Symptoms

  • Check Engine light comes on
  • The car goes into emergency mode
  • Reduced engine power
  • Problems charging the hybrid battery
  • Error message on the dashboard

Causes

  • Open or short circuit in the CAN bus
  • Problems with power supply to the battery management module
  • Malfunction of the control module itself
  • Wiring harness damage
  • Software problems

How to Fix

  1. Check the integrity of the CAN bus and connections
  2. Check fuses and module power supply
  3. Diagnose the battery control module
  4. Check and update software
  5. Repair only from an authorized dealer

Related codes

U01A8U01AAU01AB

Error U01A9 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the U01A9 code mean?

U01A9 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Hybrid/EV Battery Interface Control Module J

What causes a U01A9 error code?

The most common causes of U01A9 include: Open or short circuit in the CAN bus; Problems with power supply to the battery management module; Malfunction of the control module itself; Wiring harness damage.

How do I fix a U01A9 diagnostic trouble code?

To fix U01A9: Check the integrity of the CAN bus and connections. Check fuses and module power supply. Diagnose the battery control module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U01A9?

Do not drive — repair immediately

How much does it cost to fix U01A9?

The estimated repair cost for U01A9 is $167–556. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat