Code
C1102
MERCEDES-BENZ
C — Chassis
ETS/ASR, ABS Left Axle VSS Circuit Fault
Views:
UK: 23
EN: 23
RU: 58
AI status
Completed
Completed
100%
Causes
- Open or shorted sensor wiring (connector, chafing, corrosion)
- Failed wheel speed sensor (passive or active)
- Damaged or missing tone/ring/reluctor on wheel hub or bearing
- Poor sensor-to-reluctor air gap or misalignment
- Corroded or loose connector pins at ABS module or sensor
- Intermittent connection caused by movement/vibration
Symptoms
- ABS, ASR or ESP warning lamp illuminated
- Traction control and/or ABS functions reduced or disabled
- Inconsistent or frozen speedometer (depending on vehicle integration)
- Pulsating braking behavior during ABS events (may be absent)
- Fault occurs at low speeds or only when steering/suspension moves (indicates intermittent wiring)
What to check
- Read stored faults with a Mercedes-capable scan tool; note freeze frame and fault status (permanent/intermittent)
- Visually inspect left axle wheel speed sensor and connector for corrosion, damage, dirt or broken locking tab
- Inspect wiring along control arm/hub for chafe, pinches, or broken insulation; wiggle harness while monitoring live data to reproduce fault
- Check tone/reluctor ring condition (missing teeth, heavy rust, cracks) and sensor mounting/alignment
- Clear codes, perform a test drive and re-scan to confirm fault reproducibility
- Use a known-good sensor or swap sensors (if allowed) to determine if fault follows sensor or wiring
Signal parameters
- Passive (inductive) sensor: generates AC voltage pulses proportional to wheel speed — typically measurable as increasing AC mV to volts with wheel rotation; amplitude increases with speed
- Active (Hall or magnetoresistive) sensor: digital square/pulsed output referenced to ground and supply (commonly 0–5 V) with frequency proportional to wheel speed; idle/no-rotation = steady 0 V or defined static level
- Resistance (passive sensors): typical ballpark values may be several hundred to a few thousand ohms — consult factory data for exact spec
- Frequency: signal frequency rises with vehicle speed (tens to few hundred Hz at road speeds); waveform should be clean and consistent without dropouts
- Open-circuit: infinite resistance; short to ground or battery: near 0 Ω — any of these conditions is a fault
Diagnostic algorithm
- Confirm manufacturer-specific fault description and freeze-frame data with diagnostic tool
- Visually inspect left-axle sensor, harness, and connector; repair obvious damage or corrosion and re-tighten connectors
- With ignition on, backprobe sensor connector and monitor live signal on scan tool while rotating wheel by hand or using wheel lift; observe for pulses or AC voltage
- If no signal, measure sensor resistance (if passive) and compare to factory spec; if active, verify sensor supply/reference voltage and ground at connector
- If wiring looks intact but signal absent/intermittent, perform an oscilloscope check across sensor output and ground while rotating wheel to view waveform and dropouts
- If waveform is irregular or amplitude low, inspect reluctor ring for missing teeth, heavy rust, debris or magnetic interference; repair or replace as needed
- Wiggle wiring and harness at suspension articulation points while monitoring signal to reveal intermittent breaks
- If sensor and wiring check good, test/replace sensor with a known-good unit or swap to see if fault follows sensor
- If wiring and sensor are good but fault persists, inspect/replace ABS module connector and pin continuity; as last resort consider ABS control module fault and consult factory procedures before module replacement
- After repair, clear codes and perform a road test to verify proper function and that fault does not return
Likely causes
- Corroded/loose sensor connector at left axle
- Damaged wiring harness near wheel (bending point or hub area)
- Contaminated or failed left axle wheel speed sensor
- Damaged/missing reluctor ring (broken teeth, heavy rust, debris)
Fault status
Status
Left-axle wheel speed sensor circuit fault detected by ABS/ETS/ASR control unit. Fault stored; ABS/ASR/ESP lamp may be illuminated. Condition may be logged as open, short, intermittent or implausible signal.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
Similar codes
HTML Workshop Manuals AI manual library for MERCEDES-BENZ Click to show available manuals 25
MERCEDES-BENZ 2015 B Electric Drive
HTML ManualMERCEDES-BENZ 2000 C 230K (Motor 111)
HTML ManualMERCEDES-BENZ 2000 C 280 (Motor 112)
HTML ManualMERCEDES-BENZ 2000 C 43 AMG (Motor 113)
HTML ManualMERCEDES-BENZ 2000 CL 500 113
HTML ManualMERCEDES-BENZ 2000 CLK 320 (Motor 112)
HTML ManualMERCEDES-BENZ 2000 CLK 320 Cabriolet (Motor 112)
HTML ManualMERCEDES-BENZ 2000 CLK 430 (Motor 113)
HTML ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email