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C2100 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


C2100 is an OBD-II Code that refers to Battery Voltage Low – Circuit Voltage Below Threshold (Chrysler, Dodge, Jeep)


A C2100 code is a manufacturer specific diagnostic trouble code that relates to Chrysler, Dodge, Jeep makes and vehicles and is problem of the chassis electrical system when the circuit voltage is below the threshold.

The C2100 OBDII fault code is set when the ABSECU power supply voltage drops below 9.7 ± 0.3 V during driving.


Common causes for this code include:

  • Problematic vehicle battery
  • Loose Battery terminal 
  • Fusible link malfunction
  • Issues with vehicle charging system
  • Bad Anti-Lock Brake System (ABS) Module
  • Faulty (ECM)


The symptoms of a C2100 code are:


To diagnose a C2100 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect all wiring and connectors for damage, loose, or shorted connections.
  3. Check the vehicle battery voltage with a voltmeter to ensure it is within specifications.
  4. Check the charging system to make sure it is operating correctly.
  5. If all of these checks are normal, then the next step would be to check the ABS module for proper operation and then ECM.

Also Read: How Long does it take a Car Battery to Charge

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a C2100 code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking for voltage at the vehicle battery.
  • Not properly diagnosing the charging system.
  • Replacing parts without first checking for proper operation.

How serious is this?

A C2100 code is a serious code that can cause major issues with the vehicle if it is not diagnosed and resolved in a timely fashion.

If the charging system is not operating correctly, then the battery will eventually go dead and the vehicle will not start.

What repairs can fix the code?

repair manuals

The following are solutions that may fix this problem:

  • Repair or replace any wiring that is damaged
  • Check and repair charging system
  • Replace the battery
  • Repair or replace the ABS module
  • Repair or replace the ECM

Related codes

A C2100 is related to and may be accompanied by the following codes:

C2101 – Battery Voltage High – Circuit Voltage Above Threshold

C2102 – Battery Voltage Low – Circuit Voltage Below Threshold (Ford)

C2103  – Battery Voltage Low – Circuit Voltage Below Threshold (GM)

C2104 – Battery Voltage Low – Circuit Voltage Below Threshold ( Mazda)


In conclusion, the C2100 code is a diagnostic trouble code that refers to a problem with the battery voltage being below the threshold. This code can be caused by a variety of issues, such as a problem with the vehicle battery, loose battery terminal, fusible link malfunction, or issues with the vehicle charging system. If this code is not diagnosed and resolved in a timely manner, it can lead to major issues with the vehicle, such as the battery going dead and the vehicle not starting.