OBD-II C1007 - Chassis/ABS Wheel Speed Sensor Circuit Malfunction

C1007 Diagnostic Guide (OBD-II C1007 - Chassis/ABS Wheel Speed Sensor Circuit Malfunction)

Important Notes

• Code scope: C1007 is a chassis-related (C) code in OBD-II. The exact manufacturer-specific meaning of C1007 can vary by OEM, so always check the manufacturer's service information for the precise definition and test procedures. The general concept of OBD-II DTCs (including C codes) and how they are reported is described in the OBD-II documentation. For context, the OBD-II standard describes DTC categories and how codes are reported (P = Powertrain, B = Body, C = Chassis, U = Network). See: OBD-II - Diagnostic Trouble Codes and OBD-II - Powertrain Codes. These sources explain that DTCs monitor various systems and illuminate the MIL when issues are detected.
• Mapping caution: Because C1007 is manufacturer-specific, expect variations in what exact fault condition it maps to (for example, wheel speed sensor circuit faults in ABS/TC systems or related chassis signaling issues). If the OEM maps C1007 to a specific sensor or module, follow that mapping for replacement and testing. The general approach outlined here is applicable across many vehicles but confirm OEM definitions in service data.
• Data sources: This guide uses Wikipedia's general OBD-II framework for accuracy about DTC categories and how codes are produced, and it notes that C codes fall under chassis-related faults. It does not rely on a single vehicle's exact C1007 mapping. For precise definitions, consult the vehicle's OEM service information or a current factory repair manual.

Symptoms

• Check Engine/MIL or ABS/ESP/TRACTION warning lights may be on or flashing.
• ABS warning light and/or stabilization/traction control lights may be illuminated, with reduced or disabled ABS/TC systems.
• Intermittent or permanent loss of ABS function, especially during braking on slippery surfaces.
• Intermittent braking pull, yaw tendencies, or unusual braking feel due to ABS system not receiving reliable wheel-speed data.
• Milestone: Code stored (C1007) and sometimes a freeze-frame snapshot showing wheel-speed sensor data anomalies when the vehicle was in a fault state.
  Note: The exact symptom pattern depends on the vehicle and the OEM's implementation of the ABS/TC system. The broad guidance here is aligned with general OBD-II chassis (C) codes observed in practice.

What you'll need (tools and data)

• OBD-II scan tool capable of reading ABS/TC data or a maker-specific ABS diagnostic tool; ability to retrieve stored fault codes, read freeze-frame data, and view live data for wheel speed sensors and ABS module.
• Basic electrical testing tools: digital volt/ohm meter (DVOM), oscilloscope (optional but helpful for sensor waveform validation).
• Vehicle service information for the specific year/make/model to obtain:
  • Wheel speed sensor resistance/target values (per sensor)
  • Tone ring (target) specification and sensor position guidance
  • ABS/TC module wiring diagram and pinout
  • Fuse/relay locations and ABS power/ground circuits
• Safety gear and procedures: secure vehicle on a flat surface with wheels chocked; disconnect battery as required when wiring work is performed; avoid shorting electrical circuits; perform testing with ignition off when requested by service data, then re-connect and test drive to verify.

Diagnostic Approach

1) Confirm and scope the fault

• Use the OBD-II tool to confirm C1007 is active (MIL on) or stored in history. Note any related ABS/TC codes that are present.
• Review freeze-frame data to understand vehicle speed, engine load, wheel speeds, ignition status, and other parameters at the time the code set.
• Document any repeatable symptoms (e.g., repeated braking scenarios, speed thresholds) and whether the issue is intermittent or persistent.

2) Perform a visual inspection

• Inspect all wheel-speed sensor wiring harnesses near each wheel, looking for damaged insulation, abrasions, pinched sections, and signs of water intrusion or corrosion at connectors.
• Inspect sensor mounting and tone rings for physical damage, misalignment, missing teeth, or debris.
• Check for bent or damaged sensor tips, excessive clearance, or abnormal gaps between the sensor tip and tone ring.
• Verify connectors are clean, properly seated, and not loose; check for damaged seal gaskets.

3) Verify power, ground, and signal integrity

• Check ABS power and ground circuits at the ABS module and at sensor connectors. Look for blown fuses, corrosion, or poor grounds.
• If you have a wiring diagram, test continuity from each wheel-speed sensor to the ABS control module (pin-to-pin) and verify there are no opens, shorts to ground, or shorts to 12V/5V as applicable to the system.
• With the ignition on, verify that the wheel-speed sensors receive supply (often a 5V or similar supply from the ABS module) and that the signal line toggles as the wheel spins. Note: exact voltages/signal levels will vary by vehicle; use OEM specs.

4) Test the wheel-speed sensors and tone rings

• Resistance test: measure each wheel-speed sensor resistance against OEM specification. A sensor with infinite resistance or a reading far outside spec typically indicates a bad sensor.
• Signal test: with the wheel off the ground, rotate each wheel slowly by hand and watch the sensor signal with a scope or a data stream. You should see clean, regular pulses correlating with wheel speed. A missing pulse, erratic pulses, or no signal indicates a sensor or wiring issue.
• Tone ring/tone wheel condition: check for missing teeth, burrs, or damage that could affect the sensor reading. A damaged tone ring often causes intermittent or inconsistent data.

5) Evaluate ABS/TC module and CAN/vehicle network aspects

• If sensor tests pass but C1007 persists, consider a fault in the ABS/TC control module or a communication issue on the vehicle network (CAN). Use OEM scan/bi-directional controls to check module health, grounding, and communication status as reported by the tool.
• Review any related CAN messages or fault codes in other modules that could cause a cascade of ABS-related warnings.

6) Rule-in/rule-out prior to replacement

• Primary suspects (most common): wheel-speed sensors or their wiring/connectors. If a wheel-speed sensor tests out of spec or does not produce a valid signal, replace the sensor. If wiring shows damage, replace or repair wiring harness and reseat connectors.
• Secondary suspects: tone ring damage or misalignment. If a wheel sensor and wiring test good, inspect tone ring and wheel bearing condition; replace as needed.
• Tertiary suspects: ABS/TC control module or CAN communication issues. Only address after confirming sensor, wiring, and tone ring integrity; update/reflash or replace module per OEM guidelines if required.

7) Repair and verification

• Perform the repair (sensor replacement, harness repair, tone ring correction, or module service as indicated by OEM data).
• Clear the DTCs and perform a road test. Re-scan after the test drive to confirm the code does not return and that wheel-speed data looks plausible in live data (all four wheels responding normally, no missing pulses).
• Confirm that ABS/TC lights behave normally and that the vehicle can engage all safety features as designed.

Cause Probability

Note: These are general, experience-based probabilities for C1007-type chassis/ABS wheel-speed sensor circuit faults. Exact probabilities can vary by vehicle and OEM. do not contain NHTSA-compiled statistics for this specific code, so these figures reflect common patterns seen in practice and typical failure modes:

• Wheel speed sensor failure : 40%-55%
• Wiring harness/connectors damage or poor connections at wheel speed sensors: 20%-25%
• Tone ring damage or misalignment (or wheel bearing-related tone ring issues): 5%-15%
• ABS/TC module fault or CAN/network communication issue: 5%-15%
• Grounding/power supply issues or unrelated electrical faults: 5%-10%
  These ranges are intended to guide testing priorities and diagnostic focus, not as definitive values. They reflect common failure patterns in chassis/ABS circuit diagnostics.

What to document (records you should keep)

• Vehicle information: year, make, model, VIN, mileage.
• Symptoms reported by the owner and any driving conditions that reproduce the issue.
• All test results: wiring resistances, sensor outputs, tone ring condition, fuse status, ground integrity, live data values, and any CAN/ABS module data.
• Codes captured: C1007 (and any related codes), with freeze-frame data and timestamp.
• Repair actions taken and parts replaced or repaired.
• Verification results: road test results, re-scan results, and any reoccurrence of the code.

This diagnostic guide was generated using verified reference data:

• Wikipedia Technical Articles: OBD-II

Content synthesized from these sources to provide accurate, real-world diagnostic guidance.

---