C0035 on 2006-2011 Chevrolet HHR: Left Front Wheel Speed Sensor Fault Guide

What's Unique About the 2006-2011 Chevrolet HHR

For the Chevrolet HHR and its platform mates (Cobalt, G5, Ion), the wheel speed sensor is not a separate, standalone part. Instead, it is integrated into the sealed wheel hub and bearing assembly. This design means that if the sensor fails, the entire hub assembly must be replaced. This is the most common point of failure for this code on the HHR platform.

Symptoms You May Notice

• ABS warning light is on
• Traction Control (TC) warning light is on
• "Service Traction Control" or "Service ABS" message on the driver information center
• ABS and traction control are non-functional
• In some rare cases, a faulty wheel speed sensor signal can cause the transmission to enter a "limp mode" with harsh shifting.

Most Likely Causes

1. Failed Left Front Wheel Hub and Bearing Assembly 🔴 High Probability The wheel speed sensor is integrated into the hub assembly. Internal failure of the sensor's coil windings or corrosion and damage to the magnetic reluctor ring on the hub are very common over time, especially in areas with road salt.
   How to confirm: Use an ABS-capable scan tool to monitor live data from the left front wheel speed sensor while driving or spinning the wheel. A reading of 0 MPH or an erratic signal while the vehicle is moving confirms a fault in the circuit. You can also test the sensor's resistance with a multimeter at the connector; a reading of 1000-1500 ohms is typical, while an open circuit (infinite resistance) indicates failure.
   Typical fix: Replace the entire left front wheel hub and bearing assembly. 🎬 Watch: How to replace the hub and fix code C0035.
   Est. part cost: $80-$200
2. Damaged Wiring Harness or Connector 🟡 Medium Probability The wiring harness is exposed to road debris, moisture, and constant movement from steering and suspension, which can lead to chafing, corrosion, or broken wires, especially at the connector where it plugs into the hub.
   How to confirm: Visually inspect the wiring from the back of the hub up into the engine bay for any signs of damage, chafing, or green corrosion inside the connector. 🎬 See this quick tip for diagnosing GM ABS wiring issues. A "wiggle test" on the harness while monitoring live data can also reveal intermittent connections.
   Typical fix: If the connector is damaged, replace the pigtail (ACDelco P/N: PT1718). If the wire is broken, repair the damaged section with a new piece of wire and weatherproof connectors.
   Est. part cost: $15-$40

Rare But Worth Checking

• Faulty Electronic Brake Control Module (EBCM): This is uncommon. Before condemning the EBCM, you must definitively rule out the hub assembly and wiring. This is typically diagnosed by a professional after all other possibilities have been exhausted. Manufacturer Bulletin #PIT5499B suggests that technicians inspect the EBCM connector for water intrusion if codes like C0035 are present.
• Separated/Damaged Reluctor Ring: A user on chevyhhr.net reported a C0035-18 (Low Signal Amplitude) code after installing a new hub. The issue was that the magnetic ring had separated from the hub body. This is a rare manufacturing defect or can be caused by damage during installation.

Diagnosis Steps

1. Connect an ABS-capable scan tool and confirm the presence of code C0035. Note any other codes or sub-faults (e.g., C0035-18 for low signal amplitude).
2. View the live data stream for all four wheel speed sensors. Spin the left front wheel by hand and check if its speed registers on the scan tool. Compare it to the right front wheel. A reading of zero or one that doesn't change smoothly indicates a problem.
3. Perform a thorough visual inspection of the left front wheel speed sensor wiring harness and connector. Look for any signs of physical damage, chafing against suspension components, or corrosion in the connector pins.
4. If the wiring looks good, disconnect the sensor and test the resistance across the two pins on the sensor side of the connector. A reading of 1000-1500 ohms is typical for a good sensor on this platform. An open circuit (OL) or short (0 ohms) indicates a bad sensor/hub.
5. If a known-good hub is installed and the code persists, the fault likely lies in the wiring harness between the sensor and the EBCM, or, rarely, the EBCM itself.
6. After repair, clear the codes. Note that the ABS light may remain on until the vehicle is driven and exceeds a speed of approximately 8 MPH, allowing the EBCM to verify the signal.

Parts You'll Likely Need

• Left Front Wheel Hub and Bearing Assembly (OEM #ACDelco FW393) — This is the most common failure. The wheel speed sensor is integrated into this assembly and cannot be replaced separately.
  Trusted brands: ACDelco (FW393), Timken (HA590243), MOOG (513263), SKF (BR930592)
  OEM price range: $150-$250
  Aftermarket price range: $80-$150
• ABS Wheel Speed Sensor Connector Pigtail (OEM #PT1718) — The connector itself can become damaged or corroded, requiring replacement to ensure a solid connection to the new hub.
  Trusted brands: ACDelco
  OEM price range: $25-$40
  Aftermarket price range: $15-$25

Related Codes That Often Appear With This One

• C0040 — This is the code for the Right Front Wheel Speed Sensor. Seeing both codes together could indicate a systemic issue like a wiring problem common to both sides or a problem with the EBCM.

Technical Service Bulletins (TSBs) & Recalls

• Special Coverage #14119: Covers sudden loss of electric power steering assist. While not directly related to C0035, it's a critical safety issue for HHR owners.
• Safety Recall #14063: Pertains to the faulty ignition switch that can shut the engine off while driving.
• Bulletin #22-NA-089: Notes that ABS and Traction Control lamps may illuminate intermittently and deactivate for an ignition cycle when codes C0035-C0051 are set.
• Bulletin #PIC5428G: States that the EBCM may set code C0035 with symptom bytes 18, 5A, or 0F, requiring the technician to access the correct wheel bearing for diagnosis.

Platform-Specific Known Issues

• Corrosion in Salt Belt Regions: In regions that use road salt during winter, the hub assemblies and their integrated sensors are highly susceptible to corrosion. This can cause premature failure of the bearing, the sensor, or both. It can also make removing the old hub from the steering knuckle very difficult.
🎬 Watch: A step-by-step walkthrough of the front wheel bearing replacement.

Mechanic-Grade Diagnostic Values

• EBCM Sensor Bias Voltage — expected: Approx. 5.0V DC at the harness connector with the sensor unplugged.. Failure: With a good sensor plugged in, the bias voltage should drop significantly (e.g., to ~0.5V). If the voltage does not drop, the sensor is likely open. If the voltage is 0V when unplugged, there is a wiring issue back to the EBCM.

Hidden / Shadow Codes Worth Checking

• C0035 0F: Signal Erratic. The EBCM is receiving a signal, but it's unstable or jumping inconsistently. This often points to a damaged magnetic tone ring on the hub, debris contamination, or a wire that is broken internally and making intermittent contact. (see via GM Tech2, GDS2, or a professional-grade scan tool capable of reading manufacturer-specific symptom bytes.)
• C0035 18: Low Signal Amplitude / Circuit Open. The signal from the sensor is present but too weak, or the circuit is open. This can be caused by an excessive air gap between sensor and ring, a wiring fault (open/short), or a completely failed sensor. (see via GM Tech2, GDS2, or a professional-grade scan tool capable of reading manufacturer-specific symptom bytes.)
• C0035 5A: Signal Not Plausible. The sensor's reading doesn't make sense when compared to data from the other three wheel speed sensors. This strongly suggests a damaged or contaminated magnetic encoder ring or an incorrect/incompatible aftermarket hub assembly. (see via GM Tech2, GDS2, or a professional-grade scan tool capable of reading manufacturer-specific symptom bytes.)

Scan Tool Commands That Help

• GM Tech2 / GDS2: Live Data > EBCM > Wheel Speed Sensor Data — This is the most critical diagnostic step. It allows the technician to view the speed readings from all four wheels simultaneously while the vehicle is driven or the wheels are spun by hand. A faulty circuit will show as 0 MPH, an erratic reading, or a speed that doesn't match the others, instantly pinpointing the problem wheel.

Wiring & Ground Locations

• EBCM — Mounted to the ABS hydraulic block (modulator), located in the engine compartment, typically on the driver's side below the master cylinder.. This module is the brain of the ABS system. All sensor signals are sent here for processing. A fault in the module itself, though rare, can cause this code.
• EBCM Ground — A primary ground point for the EBCM is typically located on the frame rail under the driver's side door area or on the engine block. A diagram for HHR ground locations can be found on enthusiast forums.. Corrosion at this main ground point can create high resistance, causing the EBCM to have an unstable reference. This can lead to misinterpretation of sensor signals and the setting of false codes like C0035.
• LF WSS Circuit at EBCM Connector — At the main EBCM electrical connector. On a typical Kelsey-Hayes module used by GM, the Left Front WSS wires are Light Blue and Yellow.. To definitively rule out a wiring problem, a technician must test for continuity and shorts from the wheel hub connector all the way back to these specific pins on the EBCM connector. This isolates the harness from the sensor and the module.

Documented NHTSA Reports

• NHTSA ODI #10440851: An owner reported that both the ABS and "Brake" lights were illuminated on the dashboard, with diagnostic codes C0035 and C0040 indicating circuit malfunctions for both front wheel speed sensors.
• NHTSA ODI #11228687: A report describes multiple indicators illuminated on the dashboard; an independent mechanic found a series of codes including C0035, C0040, and C0050, along with several communication codes.

Real Owner Repair Stories

• chevyhhr.net user 'ScareDe2' (Chevrolet HHR, year not specified) — ABS and TC lights appear immediately after accelerating, with code C0035-18 (Low signal amplitude).
  ❌ Tried (didn't work) Installing a brand new hub assembly (in fact, all four were new)., Clearing the code with a scan tool.
  ✅ What actually fixed it The user was attempting to swap the new, suspect hub from left to right for diagnosis. While pulling on the wheel to remove the hub, they forgot to disconnect the sensor and the magnetic ring separated from the new hub body, revealing it was defective. They replaced it with an old, known-good hub they had on hand, which resolved the code. This proved the 'new' part was bad out of the box.
• YouTube channel 'key word' (2014 Chevrolet Impala (similar GM system)) — C0035 with 0F (erratic signal) qualifier.
  ❌ Tried (didn't work) Previous repairs by others included two wheel bearings, an ABS control module, and a wiring harness repair.
  ✅ What actually fixed it The technician identified a broken wire *inside* the insulation of the pigtail harness. The insulation was intact, so a visual inspection would miss it. The break was found by pulling on the wire and feeling it stretch, and by bending the wire and seeing it flex in one spot with no resistance. This created an intermittent open circuit that caused the erratic signal.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Sudden Loss of Electric Power Steering (EPS) 🔴 High — Very common across 2006-2009 non-turbo models. Can occur at any time while driving, resulting in a sudden increase in steering effort. (Ref: Special Coverage Adjustment #14119 covers the replacement of the power steering motor for the life of the vehicle.)
• Faulty Ignition Switch 🔴 High — Widespread issue affecting all 2006-2011 models. The switch can move out of the 'Run' position if bumped or with a heavy keychain, causing the engine to shut off and disabling airbags. (Ref: Safety Recall #14063 (also referenced as part of the larger GM ignition switch recall). Dealers were to replace the ignition switch.)
• Stuck Automatic Shifter / Key Stuck in Ignition 🟠 Medium — Common problem where the shifter gets stuck in Park, or the key cannot be removed from the ignition after parking. Often caused by a failed shift interlock solenoid or a broken plastic actuator inside the shifter assembly.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, a used part from a junkyard is NEVER a smart choice. The wheel hub/bearing is a critical wear item with a finite lifespan. The labor involved in replacing it is significant enough that installing a used part with unknown mileage and wear is a major risk that outweighs any cost savings.

What to inspect on the donor part:

• Not applicable; do not purchase used.

Aftermarket brands forum-validated for this vehicle:

• ACDelco (OEM supplier; one user reported their ACDelco box contained a 'Timken Made in USA' bearing)
• Timken (Widely regarded as a top-tier replacement)
• SKF (Considered a high-quality alternative to Timken)

Brands owners have reported issues with on this vehicle:

• MOOG (Formerly a top brand, but recent forum discussions and reviews indicate a significant decline in quality with many parts now made in China and prone to premature failure)
• Unbranded / 'White Box' Parts (Extremely cheap parts from eBay or Amazon have a very high failure rate and should be avoided to prevent doing the job twice)

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• C0035-18 — A specific sub-fault code indicating low signal amplitude from the left front wheel speed sensor.
• C0460 — Steering Angle Sensor code that can appear alongside C0035, affecting traction control stability.
• C0040 — The equivalent code for the Right Front Wheel Speed Sensor circuit, which uses the same hub/sensor design.

Frequently Asked Questions