OBD Guide
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B0403

E/G Request NG

B0403 is an OBD-II diagnostic trouble code meaning: E/G Request NG. Common causes: open or short circuit in the can bus, corrosion of connectors.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately

Symptoms

  • Airbag light is on
  • Belt pretensioners may not work
  • Reduced effectiveness of the passive safety system

Causes

  • Open or short circuit in the CAN bus
  • Corrosion of connectors
  • Engine ECU malfunction
  • Problems with the SDM block
  • Poor grounding

How to Fix

  1. Check the integrity of the CAN bus between the engine ECU and the SDM
  2. Inspect connectors for corrosion
  3. Check module grounding
  4. Read real parameters via scanner
  5. If necessary, update the module firmware

Related codes

B0040B0050B0081

Error B0403 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the B0403 code mean?

B0403 is an OBD-II diagnostic trouble code that indicates: E/G Request NG

What causes a B0403 error code?

The most common causes of B0403 include: Open or short circuit in the CAN bus; Corrosion of connectors; Engine ECU malfunction; Problems with the SDM block.

How do I fix a B0403 diagnostic trouble code?

To fix B0403: Check the integrity of the CAN bus between the engine ECU and the SDM. Inspect connectors for corrosion. Check module grounding. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B0403?

Do not drive — repair immediately

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See also: Russian version · NationStat