C0045 on 2007-2017 Jeep Patriot: Left Rear Wheel Speed Sensor Circuit Fixes

What's Unique About the 2007-2017 Jeep Patriot

The Jeep Patriot and its Chrysler MK platform siblings (Jeep Compass, Dodge Caliber) are notoriously susceptible to this issue due to the design and exposure of the rear suspension components. A very common failure mode, especially in the salt belt, is not the sensor itself but the wheel hub assembly. Severe rust builds up on the hub and the thin metal clip that holds the sensor in place, causing the clip to disintegrate. This allows the sensor to become loose, creating an incorrect air gap to the tone ring, which generates a faulty signal. Often, the entire wheel hub and bearing assembly must be replaced because the sensor mounting point is destroyed by corrosion.

Symptoms You May Notice

• ABS warning light is illuminated
• Traction Control or ESP/BAS warning light is illuminated
• "4WD!" warning light may be on for four-wheel-drive models
• ABS and traction control systems are inoperative
• Cruise control may not function

Most Likely Causes

1. Failed Left Rear Wheel Speed Sensor 🔴 High Probability → Shop ABS Wheel Speed Sensor The sensor is exposed to water, road salt, and dirt, leading to internal corrosion and failure over time. The sensor pigtail is also vulnerable to damage.
   How to confirm: Use a scan tool with live data to monitor wheel speeds. If the left rear wheel shows 0 MPH or an erratic reading while the others report correctly, the sensor is likely bad. You can also test the sensor's circuit; as an active sensor, you should check for power (approx. 11-12V), ground, and a square wave signal with an oscilloscope when the wheel is spun.
   Typical fix: Replace the left rear wheel speed sensor. 🎬 Watch: Step-by-step guide to replacing the wheel speed sensor. The sensor is typically held in by a single bolt or a metal clip.
   Est. part cost: $25-$60
2. Failed Rear Wheel Hub / Bearing Assembly 🔴 High Probability → Shop Hub Assembly This is a signature failure on the Patriot/Compass/Caliber platform. The magnetic tone ring is integrated into the wheel hub seal. Rust builds up between the hub and the knuckle, destroying the sensor's retaining clip or the tone ring itself, causing a bad signal. This is extremely common in northern climates.
   How to confirm: After removing the sensor, inspect its mounting point on the hub. If the metal clip is rusted away, loose, or the area is severely corroded, the hub is the problem. A visual inspection of the tone ring (the black magnetic strip on the hub) may show cracks, debris, or damage.
   Typical fix: Replace the entire rear wheel hub and bearing assembly. 🎬 See this walkthrough for replacing the hub and bearing.
   Est. part cost: $70-$150
3. Damaged Wiring or Connector 🟡 Medium Probability The wiring harness runs along the suspension and can be damaged by road debris, improper jacking, or corrosion at the connector plugs. Wires can chafe and break near mounting clips or where the harness passes through the body.
   How to confirm: Visually inspect the entire length of the wiring from the sensor to where it enters the vehicle body. Check for chafed wires, breaks, or corrosion inside the connector pins. Perform a continuity test with a multimeter from the sensor connector to the ABS module connector.
   Typical fix: Repair the broken section of wire or replace the connector pigtail. In severe cases, a harness section may need replacement, which can be costly.
   Est. part cost: $15-$40 for a pigtail, much higher for a harness.

Rare But Worth Checking

• Faulty ABS Control Module: → Shop ABS Control Module This is uncommon. Suspect the ABS module only after thoroughly testing the sensor, wiring, and hub, and especially if multiple, unrelated ABS codes are present.

Diagnosis Steps

1. Connect an OBD-II scanner capable of reading ABS codes to confirm C0045 is the active code.
2. Use the scanner's live data function to view the wheel speed from all four sensors while driving slowly or spinning the wheel by hand. Confirm that the left rear sensor reads differently (e.g., 0 MPH or erratic) than the other three.
3. Safely raise and support the vehicle. Remove the left rear wheel.
4. Visually inspect the wheel speed sensor and its wiring harness for any obvious signs of damage, such as breaks, chafing, or melted sections. Pay close attention to where the harness is clipped to the suspension.
5. Disconnect the sensor and inspect the connector for corrosion, moisture, or bent pins.
6. Remove the sensor (typically held by a clip or a single 10mm bolt) and inspect its tip for metallic debris. Crucially, inspect the mounting location on the hub for excessive rust or damage. Check if the sensor's retaining clip is intact or has rusted away.
7. If the hub is severely rusted and the sensor was loose, the hub assembly is the confirmed cause.
8. If the visual inspection is inconclusive, test the harness-side connector. Check for a reference voltage (should be around 12V) and a good ground.
9. If the harness tests good, the sensor is the most likely culprit. If the harness tests bad, check for continuity and shorts between the sensor connector and the ABS module connector.

Parts You'll Likely Need

• Rear Wheel Speed Sensor (OEM #5105573AA (or subsequent revisions)) — This is a common failure point for code C0045 due to its exposure to the elements and is the first part to suspect after checking for rust.
  Trusted brands: Mopar, Standard Motor Products (SMP), Dorman (970-056), SKP (SK970056)
  OEM price range: $70-$100
  Aftermarket price range: $25-$60
• Rear Wheel Hub and Bearing Assembly (OEM #5105770AG (4WD), 5105771AG (FWD) (verify by VIN)) — Often required on the Patriot if rust has damaged the sensor's mounting point or the integrated magnetic tone ring. This is a very common root cause in rust-belt states.
  Trusted brands: Timken (HA590435 for 4WD), MOOG (512333 for 4WD), SKF, TRQ
  OEM price range: $200-$280
  Aftermarket price range: $70-$150

Technical Service Bulletins (TSBs) & Recalls

• TSB 08-019-07: Affects 2007 models, involves a software flash for the ABS module to prevent false activation at startup. While not a direct fix for C0045, it shows a history of software-related ABS issues on early models.

Platform-Specific Known Issues

• A recall (NHTSA ID: F50) was issued for some 2007 model year Patriots for the ABS control module software, but this was for reprogramming the module, not replacing sensors.
• TSB 08-019-07 was released for 2007 models to update ABS control module software to address a false ABS activation on startup, but it is not directly related to the C0045 code.
• The primary vehicle-specific issue is the propensity for the rear hub assembly to rust so severely that it can no longer hold the ABS sensor in the correct position, which is the root cause of the C0045 code in a large percentage of cases, especially in regions that use road salt.

Documented NHTSA Reports

While the following records involve other manufacturers, they highlight the cross-platform nature of the C0045 code and its common mechanical causes. For instance, NHTSA ODI #11219167 describes a case where the left rear wheel speed sensor encoder ring was broken, necessitating the replacement of both the sensor and the rear hub assembly. Similarly, NHTSA ODI #11165895 notes a service center recommendation to replace the left rear hub bearing assembly to resolve the C0045 code. In some instances, such as NHTSA ODI #10382746, dealers have attempted to resolve C0045 and related codes by erasing them and reprogramming software. Finally, NHTSA ODI #11399819 illustrates that C0045 can sometimes appear alongside fuel system codes, though this is less common for the Patriot platform.

Mechanic-Grade Diagnostic Values

• Wheel Speed Sensor Signal Voltage (at sensor connector, backprobed) — expected: A digital square wave that switches between approximately 1.6V and 0.8V (a 0.6V to 0.8V drop). The frequency of the wave increases with wheel speed. Some sources state the sensor receives battery voltage (11-12V) and pulls it down to create the signal.. Failure: A flat line (no signal), a voltage that doesn't change when the wheel is spun, or a noisy/erratic waveform indicates a failed sensor, bad tone ring, or wiring issue.
• Wheel Speed Sensor Supply Voltage (at harness connector, unplugged) — expected: Approximately 11-12V (battery voltage) on the power supply wire with the key on.. Failure: Low or no voltage indicates a wiring problem between the ABS module and the sensor connector.
• Wheel Speed Sensor Ground — expected: Good continuity to chassis ground on the ground wire.. Failure: High resistance or an open circuit indicates a bad ground connection, which is a common failure point.

Hidden / Shadow Codes Worth Checking

• C1041 / C1043: Left Rear Tone Wheel Performance. While C0045 points to a general circuit fault (open, short), these codes specifically indicate that the signal being received is erratic or implausible, often pointing directly to a damaged tone ring on the hub assembly or a loose sensor creating an incorrect air gap. (see via A professional-level scan tool capable of reading Chrysler/Jeep-specific ABS codes.)

Scan Tool Commands That Help

• wiTECH (Chrysler/Jeep Dealer Tool): View Live Data - Wheel Speed Sensors — This is the primary and most effective first step. Observing all four wheel speeds in real-time while driving will immediately confirm if the left rear sensor is the one providing an erratic or zero MPH reading compared to the others.
• wiTECH (Chrysler/Jeep Dealer Tool): ABS Module Reprogram / Flash — Used to update the ABS module's software. While not a direct fix for a hardware-related C0045, it's relevant if TSBs or recalls apply to the vehicle for software-related ABS issues.
• wiTECH (Chrysler/Jeep Dealer Tool): Proxi Alignment Procedure — This procedure is required after replacing or reprogramming the ABS module to ensure it communicates correctly with other modules on the vehicle's network.

Wiring & Ground Locations

• ABS Module — Located in the engine compartment, typically mounted to the hydraulic control unit (the metal block with brake lines attached), often found near the firewall on the driver's side.. This is the computer that receives the signal from the left rear wheel speed sensor. All wiring for the sensor circuit ultimately terminates here, making its connector a key test point for diagnosing a wiring fault.
• Left Rear WSS Connector — The sensor's electrical connector is located inside the vehicle, in the rear cargo area. The spare tire cover panel must be removed to access it. The wire passes through a grommet in the floor to the sensor at the wheel hub.. This is a common point of failure due to moisture intrusion. It's also the easiest place to disconnect the sensor to test the harness and sensor sides of the circuit independently.
• G304 — A chassis ground point located under the driver's seat.. A wiring diagram indicates this ground is used by the ABS system. A loose or corroded ground here can cause various difficult-to-diagnose electrical issues, including erratic sensor readings.
• ABS Pump/Valve Fuses — In the main fuse box under the hood. Specifically, Fuse #34 (30A) for the ABS Valve and Fuse #35 (40A) for the ABS Pump.. While a blown fuse here would likely cause more codes than just C0045, checking them is a quick and essential first step in any ABS diagnosis.

Real Owner Repair Stories

• YouTube - South Main Auto Repair LLC (Jeep Compass (MK Platform mate)) — ABS, 4WD, and Traction Control lights on. Code C1041 Left Rear Tone Ring Performance.
  ❌ Tried (didn't work) The vehicle had already been fitted with a new wheel speed sensor, brake pads, rotor, caliper, and wheel hub/bearing assembly on the left rear.
  ✅ What actually fixed it The new aftermarket wheel hub/bearing assembly was defective. An oscilloscope showed anomalies and inconsistent timing in the square wave signal from the new hub's integrated tone ring compared to the known-good right side. Replacing the new, faulty hub with another new hub resolved the issue, proving that 'new' does not always mean 'good'.
• YouTube - Ivan's Garage (Jeep with persistent ABS sensor circuit code.) — ABS light on.
  ❌ Tried (didn't work) Multiple parts had been replaced without fixing the issue.
  ✅ What actually fixed it An open in the signal wire was found. The technician tested for voltage at the ABS module connector (good), then at the sensor connector (bad), and then at an intermediate connector in the fender well (good). This isolated the break to the section of harness between the fender well connector and the firewall, which was then repaired.
• YouTube - Jeep Patriot 4x4 ABS Light, Rear Hub & Bearing Replacement (2010 Jeep Patriot 4x4) — ABS and Traction Control lights on. Code C1043 for the Left Rear Wheel.
  ❌ Tried (didn't work) Initial diagnosis went straight to visual inspection.
  ✅ What actually fixed it A visual inspection revealed the metal retainer for the wheel speed sensor on the hub assembly was completely destroyed by rust, causing the sensor to be loose. Replacing the entire rear hub and bearing assembly, which includes a new retainer, fixed the problem. The axle nut torque was noted as 181 ft-lbs.

OEM Part Supersession History

• 5105573AA → 5105573AB — This is a common revision update for Mopar parts. The reason is not officially stated, but it typically involves minor improvements in materials, manufacturing process, or a change in supplier to enhance durability or resolve a known issue.
  Heads up: The parts are interchangeable. 5105573AB is the correct service replacement for 5105573AA.

Model Year Variations Within This Range

• 2014-2017: For the 2014 model year, a new 6-speed Hyundai automatic transmission was introduced, replacing the continuously variable transmission (CVT) on many models. While this doesn't directly affect the wheel speed sensor part number, it represents a significant powertrain change on the platform.
• 2007-2010 vs 2011-2017: The Patriot received a facelift for the 2011 model year with revised styling and suspension tuning for increased ride height. However, the fundamental rear suspension design and the parts related to the C0045 code (hub, sensor, wiring routing) remained largely the same and are subject to the same rust-related failures.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used wiring harness pigtail from a junkyard can be a cost-effective solution if only the connector is damaged. A complete used hub assembly is generally not recommended due to the high failure rate from rust and bearing wear.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a wiring harness: Check for any signs of brittleness, cracking, or previous repairs. Ensure connector locking tabs are intact.
• For a hub assembly (if you must): Source from a vehicle in a dry, salt-free climate. Spin the bearing by hand; it should be completely silent and smooth with zero play. Visually inspect the sensor mounting clip and tone ring for any rust or damage.

Aftermarket brands forum-validated for this vehicle:

• For Wheel Hubs: Timken, SKF, and MOOG are consistently cited by mechanics as top-tier, high-quality brands that often meet or exceed OEM specifications.

Brands owners have reported issues with on this vehicle:

• Unbranded or 'white-box' hub assemblies from online marketplaces. While cheap, they have a high rate of premature failure and can even be defective out of the box, as documented in professional repair videos.

Real Owner Stories

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

Related OBD-II Codes

• C0050 — Indicates the same fault (Wheel Speed Sensor Circuit) but for the Right Rear wheel. The Jeep Patriot is prone to the same rust-related hub and sensor failures on both rear wheels.
• C0035 — Indicates a fault in the Front Right Wheel Speed Sensor Circuit. While the rear hubs are a more common failure point on this vehicle, the front sensors and wiring can fail from similar causes like corrosion or damage.
• C0040 — Indicates a fault in the Front Left Wheel Speed Sensor Circuit. This is the counterpart to C0035 and shares the same potential causes of sensor failure, wiring damage, or a bad front hub/bearing assembly.
• C1041 — This code for 'Left Rear Tone Ring Performance' was noted in a diagnostic video for a platform-mate Jeep Compass. It points specifically to the magnetic tone ring, which is integrated into the wheel hub on the Patriot. A damaged tone ring due to rust is a primary cause of the C0045 code.

Frequently Asked Questions