Chrysler 300C C2100 (2005–2010): ABS Battery Voltage Low — Diagnostic Guide

Chrysler logoChrysler-specific code — factory diagnostic data
DTC Data Sheet
CodeC2100 — ABS module battery voltage low
Platform coveredChrysler LX — 300, 300C, 300C SRT-8, Dodge Charger, Dodge Magnum
Model years2005–2010
SystemBrakes / ABS (chassis)
Fault typeVoltage Low
Monitor conditionsIgnition ON
Set conditionABS module detects system voltage less than 7.5 V
Scan toolDRB III, wiTECH, or aftermarket OBD-II with Chrysler ABS coverage (needs access to ABS module, not just the PCM)

Scope note. C2100 on the LX platform is not a circuit fault in the wiring sense — it is the ABS module reporting that its own supply voltage has dropped below 7.5 V. Same behaviour and same procedure on Chrysler 300 / 300C / 300C SRT-8 and Dodge Charger / Magnum 2005–2010. The ABS warning lamp illuminates while this DTC is active; ABS and traction/stability control are inhibited until voltage recovers, but base (non-boosted) hydraulic braking continues to work.

The ABS module on the LX platform runs continuous self-checks while the ignition is on, including a monitor of its own battery-feed voltage. When that monitor sees less than 7.5 V it sets C2100 and disables the anti-lock and stability functions until voltage is restored. This is a protective response — the module would not be able to actuate the pump and solenoids reliably at low voltage. In almost all cases the underlying cause is not an ABS problem at all; it is a weak battery, a failing alternator, or a charging-system DTC that has already been set in the PCM.

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C2100 Chrysler 300C Quick Answer

Start with the PCM, not the ABS module. Scan the PCM for charging-system DTCs first; if any are present, repair those and re-verify. If the PCM is clean, measure battery voltage with the engine running — anything under 8.2 V points to a battery or alternator fault. If the battery is good but the ABS module reports its own Power Supply Voltage under 8.2 V on the scan tool, the module itself is dropping voltage internally and needs to be replaced.

Tap to enlargeChrysler LX C2100 ABS battery-voltage circuit schematic and connector pinoutsChrysler LX ABS module battery-voltage circuit. BATT A11 feed through Integrated Power Module Fuse 17 (30A), IPM C1 pin 8, A11 14 AWG DG/RD wire, to ABS module pin 32 (FUSED B+). ABS module pin 47 (GROUND) returns via Z903 10 AWG BK/DG wire to G101 chassis ground. Bottom: physical connector views with corner pin-number reference and pins used in this circuit highlighted.MODULE – INTEGRATED POWERC1FUSE 1730A OUT8BATT A11A1114DG/RD32FUSEDB(+)47GROUNDMODULE –ANTILOCK BRAKESZ90310BK/DGG101Stroke colors show real Chrysler LX insulation colors per the 8W-01 wire color code chart. Solid = primary, dashed = tracer.CONNECTOR PIN LOCATIONSIPM C1— GREEN8765432116151413121110926252423222120191817pin 8 — A11 feed to ABS811692617ABS MODULE— BLACK13216473247pins 32 (B+) and 47 (GND)47-pin connector — corner pins labeledBold pin numbers indicate pins used in this circuit. ABS module shown with its left and right columns only (pins 17–31 are in the middle of the connector and not involved in this circuit). View shown from wire side — flip horizontally when probing the mating half.
ABS module battery-feed and ground circuit — Chrysler LX (2005–2010). Schematic on top, physical connector pin locations below.

The Diagnostic Procedure

Tools: scan tool with Chrysler ABS coverage (DRB III, wiTECH, or aftermarket equivalent), digital voltmeter, standard hand tools.

Pin mapping. The ABS module's power and ground pins on the LX platform are:

  • ABS module pin 32 = FUSED B+ (circuit A11, 14 AWG, DG/RD)  |  fed from Integrated Power Module (IPM) connector C1 pin 8 via Fuse 17 (30A)
  • ABS module pin 47 = GROUND (circuit Z903, 10 AWG, BK/DG)  |  to G101 chassis ground
  1. Read the PCM for charging-system DTCs first. This DTC must be active for the test to be valid. Turn the ignition on. With the scan tool, read and record PCM DTCs and freeze-frame information. Erase the DTCs, start the engine, and re-read.
    → Any charging-system code present: repair the charging-system DTC in the PCM first, then run the ABS Verification Test. C2100 almost always clears once the root charging fault is fixed.
    → No charging-system codes: proceed to step 2.
  2. Measure battery voltage, engine running. Start the engine. Connect a voltmeter to the vehicle battery terminals.
    → Battery voltage below 8.2 V: the charging system is not maintaining voltage. Inspect the alternator, B+ main feed, battery condition (load test), and the negative cable / engine-to-chassis grounds. Repair per service information, then run the ABS Verification Test.
    → Battery voltage above 8.2 V: proceed to step 3.
  3. Read ABS module Power Supply Voltage on the scan tool. With the engine running, select the Anti-Lock Brakes Module data list on the scan tool and read the Power Supply Voltage parameter.
    → ABS Power Supply Voltage below 8.2 V (while battery is above 8.2 V): the ABS module is dropping voltage internally. Replace the ABS module per the service information, then run the ABS Verification Test.
    → ABS Power Supply Voltage above 8.2 V: the fault is not currently present — follow the Intermittent Condition Diagnostic Procedure. Pay particular attention to the A11 feed wire from IPM C1 pin 8 to ABS pin 32 and the Z903 ground from ABS pin 47 to G101 — a high-resistance connection in either path can cause voltage to sag under load without dropping the battery-terminal reading.

Professional tip. The OEM procedure assumes the scan tool can read “Power Supply Voltage” directly from the ABS module. Generic code readers often only show PCM live data — a tool with proper Chrysler ABS support (wiTECH, DRB III, or a capable aftermarket scanner) is required to complete step 3 cleanly. If you only have a generic reader, skip to an intermittent-condition voltage-drop test: key on, engine running, measure voltage between ABS pin 32 and G101 at full load (blower and headlights on, brake pedal applied so the ABS pump is poised). More than ~0.5 V drop across either the A11 feed or the Z903 ground indicates the circuit is the real culprit, not the module.

Common Causes on LX Platform Vehicles

The factory procedure lists three possible causes for C2100, in diagnostic order:

  • ECM or PCM DTCs present — isolated by step 1. If a charging-system fault already exists in the PCM (low-charge-voltage, field-current, or alternator-related codes), C2100 is a downstream symptom; fix the root cause. This is by far the most common trigger on LX cars with aging batteries or marginal alternators.
  • Vehicle battery / charging system — isolated by step 2. Weak or failing battery, failing alternator, corroded battery terminals, dirty engine ground, or loose B+ cable. The 5.7L HEMI and 3.5L V6 both pull hard at startup in cold weather; a battery that just barely passes a load test at 60°F can drop under 7.5 V during a winter crank and latch this code.
  • Anti-Lock Brakes Module — isolated by step 3. Only condemned after the PCM is clean and the battery/charging system is confirmed good. Replacement modules for the LX platform require programming with the vehicle's VIN and often a steering-angle-sensor calibration.

Severity & Driving

While C2100 is active the ABS and traction/stability systems are inhibited — the ABS warning lamp and, on cars equipped with ESP, the ESP warning lamp will illuminate. Base hydraulic braking continues to work normally; the pedal feels the same, the fronts and rears still brake together, and the car still stops. What you lose is the anti-lock pulsing under hard braking and the ability of the stability system to intervene on slippery surfaces. Driving to a workshop is acceptable in dry conditions, with careful attention to following distance; avoid hard braking and, if the car has it, avoid using cruise control. If the root cause is a dying battery the car may also fail to restart — do not shut the engine off until you reach help.

Other model-specific diagnostic guides we've covered for Chrysler vehicles.

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FAQ

Does this apply to my Dodge Charger or Dodge Magnum?

Yes. The LX platform shares the same ABS module, the same Integrated Power Module, the same A11 feed circuit, and the same Z903 ground across Chrysler 300 / 300C / 300C SRT-8, Dodge Charger, and Dodge Magnum (2005–2010). The diagnostic procedure is identical. Only the ABS-module part number may differ between SRT-8 (Brembo-equipped) and base cars — confirm the correct replacement part number against the vehicle's VIN if step 3 points at the module.

Why should I check the PCM first when this is an ABS code?

Because the ABS module is just reporting what it sees on its supply rail — the real fault is almost always upstream in the charging system, which the PCM monitors. If the alternator is dropping output, the PCM will have set its own DTC already (low charge voltage, field-driver codes, etc.). Fixing the PCM code fixes the symptom at the ABS module. Step 1 saves you from wrongly condemning the ABS module when the alternator is the real problem.

My battery voltage is 12.4 V at rest but the ABS light came on during a cold start. Normal?

On cold days at cranking, battery voltage can briefly drop below 7.5 V even on a healthy battery — add a weak battery and the dip is deeper and longer. The ABS module latches C2100 and the light stays on until the code is cleared, even after voltage recovers. A single cold-morning occurrence is usually harmless; repeated occurrences or a light that stays on after warm-up means the battery needs a load test.

Can I drive with the ABS light on?

Mechanically yes, legally often yes, but you have lost a safety system. The car brakes normally but without anti-lock intervention — if you lock a wheel on a wet road the car will skid rather than modulate. Avoid hard braking, slippery surfaces, and cruise control until the underlying fault is fixed. If the car has ESP (stability control), that is also offline while C2100 is active.

I replaced the battery and the code came back. What now?

Either the new battery is not charging fully (alternator issue), or there is a voltage-drop problem in the A11 feed from IPM C1 pin 8 to ABS pin 32, or in the Z903 ground from ABS pin 47 to G101. Run the Intermittent Condition procedure called for in step 3 — specifically a voltage-drop test across the A11 feed and Z903 ground with the ABS pump energised. A dirty G101 ground stud on the body is a recurring offender on higher-mileage LX cars.