OBD Guide
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B1203

Diagnosis Sensor Unit

B1203 is an OBD-II diagnostic trouble code meaning: Diagnosis Sensor Unit. Common causes: wiring harness damage, malfunction of the sensor diagnostic unit. Estimated repair cost: $56–167.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–167 (est.)

Symptoms

  • Airbag light is on
  • SRS does not activate in an accident
  • Error when diagnosing the passive safety system

Causes

  • Wiring harness damage
  • Malfunction of the sensor diagnostic unit
  • Problems with SRS sensors
  • Short circuit in the circuit

How to Fix

  1. Check wiring harness for damage
  2. Check SRS system sensors
  3. Replace the sensor diagnostic unit if necessary
  4. Reset the error and re-test

Related codes

B1200B1201B1202

FAQ

What does the B1203 code mean?

B1203 is an OBD-II diagnostic trouble code that indicates: Diagnosis Sensor Unit

What causes a B1203 error code?

The most common causes of B1203 include: Wiring harness damage; Malfunction of the sensor diagnostic unit; Problems with SRS sensors; Short circuit in the circuit.

How do I fix a B1203 diagnostic trouble code?

To fix B1203: Check wiring harness for damage. Check SRS system sensors. Replace the sensor diagnostic unit if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1203?

Do not drive — repair immediately

How much does it cost to fix B1203?

The estimated repair cost for B1203 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat