C0045 on 2008-2012 Ford Escape: Left Rear Wheel Speed Circuit Causes and Fixes

What's Unique About the 2008-2012 Ford Escape

Unlike many vehicles where the sensor or hub assembly is the primary point of failure, the second-generation Ford Escape (2008-2012) and its siblings, the Mercury Mariner and Mazda Tribute, are widely known for the ABS tone ring itself failing. This ring, which is press-fit onto the CV axle shaft, is highly susceptible to rust buildup underneath it. This corrosion causes the metal ring to expand, crack, and either spin freely on the axle or develop a widened gap, leading to an impossible-to-read signal for the sensor. Many owners and technicians report this specific failure, often after a visual inspection confirms the cracked ring.

Symptoms You May Notice

• ABS warning light is on
🎬 Check this video to find your ABS brake fuse location.
• Traction control or stability control warning light is on (may show a skidding car icon)
• Unwanted ABS activation at low speeds (a grinding or pulsing feeling in the brake pedal)
• In some cases, the 4WD warning light may flash
• Brake pedal feels 'soft' or has increased travel before the ABS light comes on

Most Likely Causes

1. Cracked, Rusted, or Loose Left Rear ABS Tone Ring 🔴 High Probability The design allows moisture to get between the CV axle shaft and the press-fit tone ring. Over time, rust forms and expands, splitting the ring. This is a well-documented common failure on this specific Escape generation and its platform mates.
   How to confirm: Safely raise the vehicle and visually inspect the toothed ring on the inboard side of the left rear wheel hub. Check for visible cracks or try to spin it by hand; it should not move independently of the axle shaft. A scanner showing an erratic signal at low, steady speeds also points to this. The crack creates a wider gap that the sensor misinterprets.
   Typical fix: The old, broken ring must be removed from the CV axle shaft. The rust on the shaft must be thoroughly cleaned off with a wire brush or sandpaper. A new tone ring is then heated (some mechanics use a torch or bearing heater) and pressed or tapped onto the cleaned surface. 🎬 Watch: Step-by-step guide to installing a new ABS tone ring. Some owners have successfully used epoxy to secure a cracked ring as a temporary fix.
   Est. part cost: $15-$40
2. Faulty Left Rear Wheel Speed Sensor 🟡 Medium Probability → Shop ABS Wheel Speed Sensor
   How to confirm: Use a scan tool to monitor live data from all four wheels. If the left rear sensor reads 0 MPH while the others show speed, the sensor is likely bad. You can also swap the left and right rear sensors (if possible) to see if the code follows the sensor to the other side (e.g., becomes C0050 for the right rear). Check resistance with a multimeter (refer to service manual for specs).
   Typical fix: The sensor is typically held in by a single bolt. Unplug the electrical connector, remove the bolt, and pull the old sensor out. Clean the mounting surface before installing the new sensor. 🎬 See this walkthrough for replacing the wheel speed sensor.
   Est. part cost: $30-$70
3. Damaged Wiring or Corroded Connector ⚪ Low Probability
   How to confirm: Visually inspect the wiring harness from the sensor up into the wheel well and to the main chassis connector. Look for chafing, breaks, or green/white corrosion on the connector pins. Perform a continuity test on the wires from the sensor connector to the ABS module connector.
   Typical fix: If a small section of wire is damaged, it can be repaired with a new piece of wire and weatherproof butt connectors. If the connector is corroded, it may need to be cleaned or replaced with a pigtail kit.
   Est. part cost: $15-$50 for a pigtail connector

Rare But Worth Checking

• Failed ABS Control Module: → Shop ABS Control Module This is very uncommon. This should only be considered after the tone ring, sensor, and wiring have all been thoroughly tested and confirmed to be good. A failure inside the module's circuitry can prevent it from reading the signal from an otherwise perfect sensor.

Diagnosis Steps

1. Connect an OBD-II scanner capable of reading ABS codes to confirm C0045 is present.
2. Use the scanner to view live data for all four wheel speed sensors. Drive the vehicle slowly (5-10 mph) and watch the readings. A faulty left rear circuit will show a speed of 0, or a reading that jumps around erratically compared to the other three.
3. Safely lift and support the rear of the vehicle so the left rear wheel can be turned by hand.
4. Remove the wheel and visually inspect the ABS tone ring on the CV axle shaft. Look for obvious cracks, heavy rust, or missing teeth.
5. Attempt to move the tone ring with a screwdriver or by hand. If it moves or spins on the axle shaft, it has failed and is the cause of the code.
6. If the tone ring is intact and solid, inspect the wheel speed sensor. Check for physical damage or heavy contamination on its magnetic tip.
7. Trace the sensor's wiring harness from the wheel hub up into the vehicle body. Look for any signs of chafing, melting, or broken wires. Unplug the connector and check for corrosion or bent pins.
8. If no visual faults are found, the sensor itself is the next most likely culprit. Test its resistance with a multimeter or swap it with the right-side sensor to see if the fault code changes to C0050 (Right Rear Wheel Speed Circuit Malfunction).

Parts You'll Likely Need

• ABS Tone Ring (Reluctor Ring) (OEM #ZZC0-33-471A (Mazda number, widely cross-referenced)) — This is the most common point of failure for this code on the 2008-2012 Escape due to corrosion causing it to crack.
  Trusted brands: Dorman 917-539 (47-tooth), Standard Motor Products (SMP) ABSR3
  OEM price range: $20-$50
  Aftermarket price range: $15-$40
• Left Rear Wheel Speed Sensor (OEM #9L8Z-2C190-A) — If the tone ring is not the issue, the sensor itself is the next most likely part to have failed due to age and exposure to the elements.
  Trusted brands: Motorcraft, Bosch, Delphi, NTK
  OEM price range: $60-$90
  Aftermarket price range: $30-$70

Technical Service Bulletins (TSBs) & Recalls

• TSB 20213 (superseded by 08-3-1) - While not for this specific code, this TSB updates the workshop manual with the correct procedure for replacing wheel speed sensor rings, acknowledging that this is a serviceable part.

Platform-Specific Known Issues

• The press-fit design of the rear ABS tone rings makes them a frequent failure point due to rust buildup, a problem widely discussed in owner forums and demonstrated in repair videos for this specific generation.
• Real Owner Experience: An owner on an electric vehicle forum reported their 2008 FEH had the ABS light come on at 45,000 miles. The dealer diagnosed and replaced the cracked left front tone ring, which resolved the issue.

Mechanic-Grade Diagnostic Values

• Rear Wheel Speed Sensor Resistance (Passive 2-wire VRS) — expected: 800 - 2,700 Ohms. The key is that both rear sensors should have very similar resistance values.. Failure: A reading of infinite Ohms (open circuit), zero Ohms (short circuit), or a value significantly different from the opposing wheel's sensor indicates a failed sensor.
• Rear Wheel Speed Sensor AC Voltage Output — expected: Minimum of 0.1 - 0.25 Volts AC (100-250mV AC) when the wheel is spun by hand at approximately one revolution per second.. Failure: No AC voltage generated while spinning the wheel indicates a failed sensor or a problem with the tone ring.

Hidden / Shadow Codes Worth Checking

• C0045:06: Indicates an open circuit or missing component in the left rear wheel speed sensor circuit. (see via Requires an advanced or dealer-level scan tool (like Ford IDS) capable of reading manufacturer-specific enhanced DTCs.)
• C0045:0F: Indicates an erratic signal from the left rear wheel speed sensor. (see via Requires an advanced or dealer-level scan tool (like Ford IDS) capable of reading manufacturer-specific enhanced DTCs.)
• C0045:5A: Indicates the signal is not plausible when compared to other vehicle data (e.g., other wheel speeds). (see via Requires an advanced or dealer-level scan tool (like Ford IDS) capable of reading manufacturer-specific enhanced DTCs.)

Scan Tool Commands That Help

• Ford IDS (Integrated Diagnostic System): ABS Self Test — Use this function to retrieve any manufacturer-specific or hidden trouble codes after an initial scan.
• Ford IDS / FORScan: Live Data Graphing (PID: WSS_LR) — This is the most critical diagnostic step. Graphing the Left Rear Wheel Speed Sensor (WSS_LR) output while driving slowly will visually show dropouts or erratic signals caused by a cracked tone ring, which appear as sharp drops or a 'sawtooth' pattern compared to the smooth lines of the other sensors.

Wiring & Ground Locations

• C135 — The main electrical connector for the ABS control module, located on the ABS pump assembly in the engine compartment.. This is the termination point for the wheel speed sensor wiring. Testing for continuity and voltage should be done between the sensor connector at the wheel and the corresponding pins at this connector to rule out a wiring fault.
• G104 — On the left front of the engine compartment, near the battery.. This is a primary engine bay ground point. While not directly for the sensor, a poor ground here can introduce electrical noise or cause issues with the ABS module itself, which is also grounded in this area.
• G202 — Located on the left side of the dash.. This is an interior ground point. While less likely to be the cause, it can be related to the instrument cluster warning lights or other interior modules that communicate with the ABS system.

Real Owner Repair Stories

• YouTube user 'Valley Mobile Automotive' (2012 Ford Escape) — ABS light on, code for right front wheel speed sensor (C0040, but same principle as C0045).
  ❌ Tried (didn't work) The technician immediately suspected the tone ring despite the code pointing to the sensor.
  ✅ What actually fixed it The technician found the tone ring was not only cracked but also loose on the axle shaft. As a demonstration for a quick fix, he used glue to secure the cracked ring back together. A test drive confirmed this resolved the erratic signal and the ABS light went out, proving the loose/cracked ring was the sole cause.
• YouTube user 'FordTechMakuloco' (Ford Escape (similar generation)) — ABS light on, code for wheel speed sensor input signal missing (e.g., C1234).
  ❌ Tried (didn't work) The video focuses on direct diagnosis rather than failed attempts.
  ✅ What actually fixed it The video demonstrates using a scan tool to watch live data, showing one wheel speed sensor dropping to zero or fluctuating wildly. The cause was confirmed by visual inspection to be a cracked tone ring. The fix was replacing the tone ring after cleaning the rust off the CV axle shaft. The ABS light went out on its own during the post-repair test drive without needing to be cleared by the scan tool.

OEM Part Supersession History

• 9L8Z-2C190-A → None, this is the current OEM part number for the rear wheel speed sensor for this vehicle. — N/A
  Heads up: This part number is for vehicles without the automated parking system. Ensure you are ordering the correct part for the vehicle's options.

Diagnostic Flowchart

Other Known Issues on This Vehicle

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

• Electronic Power Steering Failure 🔴 High — Very common. The torque sensor within the steering column fails, causing a sudden loss of power assist. Can occur at any mileage. (Ref: Recall 14S05; TSB 14-0016.)
• Rear Shock Tower Rust 🔴 High — Extremely common in rust-belt states. The upper rear shock mount area rusts through, causing the shock to detach from the body.
• 6F35 Transmission Issues (2009-2012) 🟠 Medium → Shop Transmission Assembly — Common on 2009-2010 models. Issues include harsh shifts, upshift flares, and delayed engagement, particularly when cold. (Ref: TSB 10-21-9.)
• CD4E Transmission Failure (2008) 🟠 Medium → Shop Transmission Assembly — Some 2008 models may experience a loss of 2nd and 4th gear due to an internal band failure. (Ref: TSB 12-4-8.)
• Throttle Body Malfunction 🟠 Medium — Fairly common. The electronic throttle body can fail, causing the vehicle to enter a 'limp mode' with no acceleration.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A complete used CV axle assembly from a junkyard can be a cost-effective option if the donor vehicle is from a dry, salt-free region and has low mileage. This is only advisable if you can personally inspect the tone ring on the used axle for any signs of cracking or heavy rust before purchase.

Donor-vehicle mileage cap: roughly under 75000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Check the tone ring for any visible cracks, especially at the seam.
• Ensure the tone ring is not loose; it should not spin or wiggle on the axle shaft.
• Look for minimal surface rust on the axle and ring. Heavy pitting or flaking is a bad sign.
• Verify the donor vehicle is from a 'rust belt' state.

OEM-only on this vehicle (don't cheap out):

• While not strictly 'OEM-only', it is highly recommended to use either an OEM Motorcraft sensor or a reputable OE-supplier brand like Bosch or NTK. Cheap, unbranded sensors are known for high failure rates out of the box.

Aftermarket brands forum-validated for this vehicle:

• Dorman (for the tone ring, specifically the 'heavy duty' versions which are reportedly thicker than stock)
• Standard Motor Products (SMP)
• NTK (for the sensor)
• Bosch (for the sensor)

Brands owners have reported issues with on this vehicle:

• Unbranded, 'white box' sensors from online marketplaces. While the price is tempting, forum users and mechanics frequently report these parts failing immediately or having incorrect signal outputs.

Real Owner Stories

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

Documented NHTSA Reports

Related OBD-II Codes

• C0050 — This is the code for the Right Rear Wheel Speed Circuit Malfunction. It is often used as a diagnostic comparison; if the fault moves from C0045 to C0050 after swapping sensors, the sensor itself is confirmed as the failure.
• 14S05 — While not a diagnostic code, this is a major recall related to Electronic Power Steering failure, another high-frequency safety issue for this vehicle generation.
• TSB 10-21-9 — Related to transmission shifting issues (harsh shifts/flares) on 2009-2012 models, which are common known issues for this platform alongside ABS faults.
• TSB 12-4-8 — Addresses internal band failure in the CD4E transmission found in 2008 models, another common mechanical failure for this specific year.

Frequently Asked Questions