C1107

What Does Code C1107 Mean?

Diagnostic Trouble Code C1107 indicates an “ABS Function Enabled Input Circuit Failure.” This is a chassis (C-prefix) code specifically pertaining to the Anti-lock Braking System (ABS) and its integrated functions, such as Traction Control (TC) or Electronic Stability Program (ESP). The ABS control module, often referred to as the Electronic Brake Control Module (EBCM), monitors a dedicated input circuit to determine if a specific ABS-related function (like TC or ESP) has been commanded to be enabled or disabled, typically by the driver via a switch or by another vehicle control module. When the EBCM detects that the voltage or signal on this input circuit falls outside of its factory-defined parameters – e.g., an open circuit (no voltage), a short to ground (0V), or a short to voltage (battery voltage when not expected), or an incorrect digital message on a Controller Area Network (CAN) bus – it registers a C1107 fault. This failure means the EBCM cannot reliably receive or interpret the command to enable or disable these advanced braking and stability features, potentially compromising the system’s ability to respond to driver input or automatic requests for stability management.

Common Symptoms

• ABS Warning Light: The Anti-lock Brake System warning indicator on the instrument cluster will be illuminated.
• Traction Control/ESP Warning Light: The Traction Control (TC) or Electronic Stability Program (ESP) warning indicator will be illuminated, often accompanied by a “Service Stability System” message.
• Inoperative Function Switch: If the vehicle is equipped with a physical button to enable or disable TC/ESP (e.g., an “ESP OFF” button), pressing it may have no effect, or the corresponding warning light may remain illuminated regardless of the button’s state.
• Reduced Stability Control Performance: While the base ABS function may still operate, the advanced stability and traction control features may be intermittently disabled or operate with reduced effectiveness.

What Causes the Code C1107?

• Faulty Wiring or Connectors: An open circuit, short to ground, short to voltage, or high resistance within the wiring harness connecting the ABS/TC/ESP control switch, the Body Control Module (BCM), Powertrain Control Module (PCM), or the EBCM. This includes chafing, corrosion, or loose terminals.
• Defective ABS/TC/ESP Control Switch: An internal failure within the physical switch used by the driver to enable or disable stability control functions, preventing it from sending the correct signal.
• Internal EBCM Failure: The ABS/EBCM itself may have an internal fault preventing it from correctly reading or processing the input signal for the “function enabled” circuit.
• Faulty BCM or PCM: If the “function enabled” signal is routed through or generated by the BCM or PCM before reaching the EBCM, an internal fault in these modules could send an incorrect or missing signal.
• CAN Bus Communication Issues: If the “function enabled” status is communicated via the vehicle’s CAN bus, issues such as a faulty bus wire, improper termination, or another module flooding the network can disrupt the EBCM’s reception of the necessary data.

How to Diagnose and Troubleshoot

Diagnosis of C1107 requires a systematic approach, often involving a digital multimeter (DMM) and an advanced OBD-II scanner capable of accessing ABS module data.

1. Retrieve All DTCs and Freeze Frame Data: Use an OBD-II scanner to read code C1107 and any accompanying freeze frame data. Also, scan the ABS module, BCM, and PCM for any related communication (U-codes) or input circuit codes, which can help narrow down the problem area.
2. Visual Inspection: Disconnect the battery. Carefully inspect the wiring harness and connectors associated with the EBCM, the BCM, the PCM, and the ABS/TC/ESP control switch. Look for signs of chafing, cuts, corrosion, bent pins, or loose connections. Pay close attention to areas where the harness passes through firewalls or near sharp edges.
3. Circuit Integrity Check (DMM):
   • Switch Test: If equipped with a physical switch, locate its connector and, using a wiring diagram, test its operation. With the switch disconnected, use the DMM on the continuity setting (Ω) or voltage setting (if it’s a voltage-producing switch) to verify that the switch changes state as designed when pressed. Look for a clean transition from open to closed, or a specific voltage output.
   • Wiring Continuity: Disconnect the EBCM connector and the connector for the sending module (e.g., BCM, PCM, or switch). Using the vehicle’s wiring diagram, identify the specific pin for the “ABS Function Enabled” input circuit at the EBCM and its corresponding source. Perform a continuity check (Ω) between these two points. A reading of less than 5 ohms indicates good continuity.
   • Short to Ground/Voltage Check: With the EBCM and sending module/switch disconnected, check for a short to ground by placing one DMM lead on the suspect circuit wire and the other on a known good chassis ground. Any resistance reading below infinity (open circuit) indicates a short. Reconnect the battery temporarily (if safe to do so) and check for a short to voltage by measuring voltage on the suspect wire. Any voltage present when it shouldn’t be indicates a short to voltage.
   • Voltage Drop Test: If the circuit carries a voltage signal, reconnect all modules and perform a voltage drop test across the input circuit. Measure voltage at the source (e.g., switch output, BCM output) and then at the EBCM input. An excessive voltage drop (typically more than 0.2V) indicates high resistance in the wiring.
4. Power and Ground to EBCM: Verify that the EBCM is receiving proper battery voltage and has a solid ground connection as specified in the service manual. Improper power or ground can cause modules to malfunction or misinterpret signals.
5. CAN Bus Diagnostics (if applicable): If the “ABS Function Enabled” status is communicated digitally via the CAN bus, use an advanced scanner to monitor CAN bus activity. Check for missing messages from the relevant sending module to the EBCM. Verify CAN bus high and low resistance (typically 60 ohms across the bus terminals at the DLC with ignition off).
6. Module Verification: If all wiring, switches, and power/ground checks pass, and no other related codes are present, the EBCM itself may be faulty. In some cases, the sending module (BCM or PCM) could also be at fault if it’s responsible for generating the signal. This step often requires specialized diagnostic tools or replacement of the suspected module for confirmation.

Recommended Repairs and Solutions

Once the root cause of C1107 has been identified through thorough diagnosis, implement the following repairs:

• Repair or Replace Damaged Wiring/Connectors: If the diagnosis points to faulty wiring or corroded connector terminals, repair the harness using OEM-approved repair techniques (e.g., solder and heat-shrink, proper crimping) or replace the damaged section of the harness or the connector. Ensure all connections are secure and weatherproof.
• Replace Faulty ABS/TC/ESP Control Switch: If the control switch is confirmed to be defective, replace it with a new, OEM or equivalent quality component. Ensure proper reassembly of interior trim.
• Replace ABS Control Module (EBCM): If internal EBCM failure is diagnosed, replace the entire EBCM unit. Be aware that many EBCM replacements require specific programming or calibration to the vehicle’s VIN and options using a factory-level scan tool. Refer to the vehicle’s service information for detailed programming procedures. Failure to program correctly can lead to further DTCs or improper system operation.
• Replace BCM/PCM (Less Common): In rare instances where the BCM or PCM is definitively identified as the source of the incorrect signal, it will need replacement and subsequent programming/configuration. This is typically a more complex and costly repair.
• Address CAN Bus Faults: If a CAN bus issue is identified, repair the faulty bus wiring, correct any short circuits, or replace any conflicting modules that are disrupting network communication.

After any repair, clear all stored DTCs from all modules. Perform a comprehensive test drive under varying conditions to ensure the fault does not return and that the ABS, Traction Control, and Stability Control systems function correctly. If the vehicle requires specific sensor or steering angle calibrations after ABS module work, ensure these are performed as per manufacturer specifications.