OBD Guide
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P06A4

Sensor Reference Voltage D Circuit Low

P06A4 is an OBD-II diagnostic trouble code meaning: Sensor Reference Voltage D Circuit Low. Common causes: short to ground wire of the reference voltage line 5v group d, faulty sensor with breakdown of input circuit insulation to ground. Estimated repair cost: $6–56.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$6–56 (est.)

Symptoms

  • Check Engine Light Is On
  • Many associated sensor errors (pressure, position)
  • The engine is unstable or goes into emergency mode
  • Low readings of several sensors on the dashboard
  • Poor traction and unstable idle speed

Causes

  • Short to ground wire of the reference voltage line 5V group D
  • Faulty sensor with breakdown of input circuit insulation to ground
  • Damage to the wiring harness (chafing, moisture ingress)
  • Oxidation of connectors creating a parasitic current leakage path
  • Faulty internal ECU regulator

How to Fix

  1. Read all error codes and identify which sensors are connected to line D of the reference voltage
  2. Measure the voltage on the 5V line (if P06A4 it will be below normal)
  3. Disconnect sensors one at a time until normal voltage is restored
  4. After identifying the culprit sensor, measure its resistance between power and ground
  5. Replace the faulty sensor or repair the short in the wiring
  6. Reset error codes and make sure they disappear

Related codes

P06A3P06A5P06A9P0641P0651

Error P06A4 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P06A4 code mean?

P06A4 is an OBD-II diagnostic trouble code that indicates: Sensor Reference Voltage D Circuit Low

What causes a P06A4 error code?

The most common causes of P06A4 include: Short to ground wire of the reference voltage line 5V group D; Faulty sensor with breakdown of input circuit insulation to ground; Damage to the wiring harness (chafing, moisture ingress); Oxidation of connectors creating a parasitic current leakage path.

How do I fix a P06A4 diagnostic trouble code?

To fix P06A4: Read all error codes and identify which sensors are connected to line D of the reference voltage. Measure the voltage on the 5V line (if P06A4 it will be below normal). Disconnect sensors one at a time until normal voltage is restored. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P06A4?

Do not drive — repair immediately

How much does it cost to fix P06A4?

The estimated repair cost for P06A4 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

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