OBD Guide
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C2124

No Signal from Transmitter ID 4 In Main Mode

C2124 is an OBD-II diagnostic trouble code meaning: No Signal from Transmitter ID 4 In Main Mode. Common causes: open or shorted wiring harness, transmitter id 4 fault. Estimated repair cost: $56–167.

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

Symptoms

  • The SRS (airbag) malfunction indicator light comes on.
  • Incorrect operation of the passive safety system
  • The vehicle may not recognize the impact sensors

Causes

  • Open or shorted wiring harness
  • Transmitter ID 4 fault
  • Problems with the restraint system ECU
  • Corrosion of contacts or connectors

How to Fix

  1. Check the integrity of the wiring harness and connectors
  2. Test ID 4 transmitter (shock sensor or other SRS component)
  3. Check the power and ground of the transmitter
  4. If necessary, replace the transmitter or repair the wiring harness
  5. Reset the error and check again

Related codes

B0100B0101B0102

FAQ

What does the C2124 code mean?

C2124 is an OBD-II diagnostic trouble code that indicates: No Signal from Transmitter ID 4 In Main Mode

What causes a C2124 error code?

The most common causes of C2124 include: Open or shorted wiring harness; Transmitter ID 4 fault; Problems with the restraint system ECU; Corrosion of contacts or connectors.

How do I fix a C2124 diagnostic trouble code?

To fix C2124: Check the integrity of the wiring harness and connectors. Test ID 4 transmitter (shock sensor or other SRS component). Check the power and ground of the transmitter. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C2124?

Do not drive — repair immediately

How much does it cost to fix C2124?

The estimated repair cost for C2124 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat