C0045 on 2007-2012 Dodge Caliber: Left Rear Wheel Speed Sensor Circuit Causes and Fixes

What's Unique About the 2007-2012 Dodge Caliber

The Dodge Caliber shares its Chrysler MK platform and rear suspension design with the Jeep Patriot and Compass. This platform is infamous for a specific weakness where the rear wheel hub assembly is highly prone to severe rust, especially in salt-belt regions. This corrosion flakes off and directly destroys the thin metal clip that holds the wheel speed sensor in place. This allows the sensor to become loose, creating an incorrect air gap with the magnetic tone ring or even falling out completely. This means that even if the sensor itself hasn't failed electronically, a rusted hub will cause the C0045 code, making a simple sensor swap an ineffective repair.

Symptoms You May Notice

• ABS warning light is on
• Traction Control (ESP/BAS) warning light is on
• Brake warning light may be on
• Cruise control is disabled
• In rare cases, unwanted ABS activation at low speeds if the signal is erratic but not completely lost

Most Likely Causes

1. Rusted/Failed Rear Wheel Hub Assembly 🔴 High Probability → Shop Hub Assembly The Caliber and its platform mates (Jeep Patriot/Compass) are known for significant rust accumulation on the rear hubs, especially in regions with road salt. The design allows moisture and debris to collect, which flakes off and destroys the integrated magnetic tone ring or, most commonly, breaks the sensor's mounting clip.
   How to confirm: Remove the left rear wheel and the wheel speed sensor (10mm bolt). Visually inspect the sensor's mounting point on the hub. If the area is severely corroded, the metal clip is broken or disintegrated, or the sensor is loose in its bore, the hub is the culprit and must be replaced. 🎬 Watch this walkthrough for replacing the rear wheel hub assembly. Also inspect the magnetic ring on the hub for cracks, debris, or metallic 'fuzz' that can distort the signal.
   Typical fix: Replace the entire rear wheel hub and bearing assembly. The new hub will have a fresh tone ring and a proper mounting surface for the sensor. This is the only permanent fix if the original hub's sensor mount is compromised.
   Est. part cost: $70-$150
2. Failed Left Rear Wheel Speed Sensor 🔴 High Probability → Shop ABS Wheel Speed Sensor The sensor is exposed to water, salt, and road debris, which can cause internal failure or damage to the sensor head over time. It can also be damaged during removal if seized in a corroded hub.
   How to confirm: Use a scan tool with live data to confirm the left rear wheel speed reads 0 MPH while driving. If the hub inspection passes, the sensor is the next likely culprit. Testing involves checking for a square wave signal with an oscilloscope, or checking resistance with a multimeter. A typical resistance value for this type of sensor is between 800-2,500 Ohms. An open circuit (infinite resistance) or short (near zero) indicates a failed sensor.
   Typical fix: Replace the left rear wheel speed sensor. The sensor is held by a 10mm bolt, and its harness plugs in behind the trunk's interior trim panel.
   Est. part cost: $25-$80
3. Damaged Wiring or Connector 🟡 Medium Probability The wiring harness runs along the suspension and is exposed to road debris, moisture, and flexing, which can lead to chafing or breaks over time. The connector inside the trunk can also become corroded or damaged.
   How to confirm: Visually inspect the entire length of the harness from the sensor to the grommet where it enters the body. Check for breaks, chafed insulation, or corrosion in the connector pins inside the trunk. Perform a continuity test from the sensor connector to the ABS module connector using a multimeter.
   Typical fix: Repair the damaged section of wire or replace the connector pigtail. Ensure the repair is sealed against moisture.
   Est. part cost: $15-$40

Rare But Worth Checking

• Failed ABS Control Module: → Shop ABS Control Module This is the least likely cause. A faulty ABS module will typically trigger multiple wheel speed sensor codes, communication codes (like U-codes), or internal module failure codes, not just a single one for the left rear. Only consider this after definitively ruling out the sensor, hub, and wiring.

Diagnosis Steps

1. Connect an ABS-capable scan tool to confirm 🎬 Watch: A step-by-step guide to diagnosing ABS sensor problems. C0045 is the active code and check for any other related DTCs.
2. Use the scan tool's live data feature to monitor all four wheel speeds while driving slowly. Confirm that the left rear wheel speed reads 0 MPH or is erratic compared to the others.
3. Safely raise and support the vehicle. Remove the left rear wheel.
4. Visually inspect the wheel speed sensor wiring harness for any signs of physical damage, chafing, or corrosion from the wheel well into the trunk.
5. Remove the 10mm bolt holding the sensor to the hub. Carefully attempt to remove the sensor, which may be seized.
6. Crucial Step: Thoroughly inspect the wheel hub. Check for heavy rust buildup, especially around the sensor mounting hole. Verify that the clip that holds the sensor is intact and not broken or rusted away. If the clip is gone, the hub must be replaced.
7. Inspect the magnetic tone ring on the hub for cracks, debris, or missing sections. Clean any metallic 'fuzz' off the ring.
8. If the hub is severely rusted or the sensor clip is broken, the hub assembly is the primary failure and must be replaced. It is wise to replace the sensor at the same time.
9. If the hub looks good, the sensor is the next most likely cause. Trace the sensor wire into the trunk, disconnect it, and install the new sensor.
10. If a new sensor and hub do not resolve the issue, perform continuity and voltage tests on the wiring harness from the sensor connector back to the ABS module connector to check for an open or shorted wire.
11. After the repair, clear the codes with a scan tool. A short drive should confirm the fix and that the warning lights stay off.

Parts You'll Likely Need

• Rear Wheel Hub and Bearing Assembly (OEM #5105770AC (superseded by 5105770AD, 5105770AH)) — A very common failure on the Caliber platform where rust destroys the integrated tone ring or the sensor's mounting point, making a new hub necessary for the repair.
  Trusted brands: Timken, SKF, MOOG, TRQ
  OEM price range: $180-$270
  Aftermarket price range: $70-$150
• Left Rear ABS Wheel Speed Sensor (OEM #5105063AA (or 5105063AC)) — This is the sensor that directly reports wheel speed. It can fail internally or be damaged by a deteriorating hub. Note: The part number 5105573AB cited in Pass 1 is for the FRONT left sensor.
  Trusted brands: Delphi, NTK (NGK), Standard Motor Products (SMP), Mopar
  OEM price range: $60-$100
  Aftermarket price range: $25-$80

Platform-Specific Known Issues

• There was a recall (NHTSA campaign 06V433000) for incorrect length rear wheel hub mounting bolts that could affect the park brake, but it is not directly related to the ABS sensor function.
• There was a recall (NHTSA campaign 07V152000) for ABS control module software that could cause rear brake lock-up, requiring a reprogram. While not a direct cause of C0045, it highlights known issues with the ABS system on early models.

Mechanic-Grade Diagnostic Values

• Wheel Speed Sensor Resistance — expected: 800 - 2,500 Ohms. Failure: A reading of infinite resistance (Open Loop) or near-zero resistance (Short Circuit).
• Wheel Speed Sensor AC Voltage Output — expected: Minimum of 0.2 VAC (200mV) while spinning the wheel by hand at about one revolution per second.. Failure: Voltage is less than 0.2 VAC or does not increase as wheel speed increases.
• Rear Hub Assembly Mounting Bolts Torque — expected: 77 ft-lbs (105 Nm). Failure: N/A - This is an installation specification.
• Rear Axle Nut Torque (FWD Models) — expected: 180 ft-lbs (244 Nm). Failure: N/A - This is an installation specification.

Scan Tool Commands That Help

• Chrysler WiTech or advanced aftermarket (Autel, AlfaOBD): Initialize ABS / Proxy Alignment — This function is mandatory after replacing the ABS control module. It programs the vehicle's VIN into the new module to allow it to communicate with other vehicle systems. Failure to perform this step will result in a C2200 code and the system will not function.
• Chrysler WiTech or advanced aftermarket (Autel, AlfaOBD): ABS Bleed — This is a required service function after replacing the ABS hydraulic control unit (HCU) or module. It cycles the internal pump and valves to purge any trapped air from the brake system, which cannot be removed with a standard manual bleed.

Wiring & Ground Locations

• ABS Control Module — In the engine compartment, located on the driver's side, behind the headlight and near the shock tower.. This is the destination for the left rear wheel speed sensor signal. The connector here is the final point for continuity testing from the sensor.
• Left Rear Wheel Speed Sensor Wires — The harness contains a Green with Blue stripe wire and a Green with Black stripe wire.. Knowing the specific wire colors is essential for performing accurate continuity tests between the sensor connector in the trunk and the ABS module connector in the engine bay.
• G303 Ground — Located behind the left quarter panel/in the left side of the luggage compartment.. This is a primary body ground point in the rear of the vehicle. While not directly tied to the ABS module itself, poor grounding in this area can cause electrical noise and intermittent issues with components located in the rear, including the sensor circuit.
• ABS Module Ground (G105) — Some diagrams suggest a ground designated G105 serves the ABS module, located on the body near the module itself.. A corroded or loose main ground for the ABS module can cause a variety of unpredictable codes, including what appears to be a single sensor fault.

Real Owner Repair Stories

• YouTube channel 'JasmineFatherGarage4k' (Dodge Caliber (year not specified, but within the 2007-2012 range)) — ABS light on, scan tool shows C0045 for the left rear wheel speed sensor.
  ❌ Tried (didn't work) Replacing the left rear wheel speed sensor with a brand new part did not resolve the issue; the live data still showed 0 MPH from that wheel.
  ✅ What actually fixed it A continuity test revealed an open circuit in the wiring harness between the sensor connector in the trunk and the ABS module in the engine bay. The technician diagnosed a broken wire within the harness, which runs from the trunk, under the driver's side sill plates, through the firewall, and to the module.

OEM Part Supersession History

• 68038075AA → P68038075AA — Standard part number update/revision.
  Heads up: This is an ABS Control Module part number for early models (approx. 2007-2008). Modules are highly specific to FWD/AWD and brake type (disc/drum). A replacement module, new or used, requires VIN programming with a compatible scan tool to function.
• 5105770AC → 5105770AD, 5105770AH — Revisions to the rear wheel hub assembly.

Model Year Variations Within This Range

• 2010-2012: ABS pump and module part numbers changed for the 2010 model year. For example, P68078999AA is listed for 2010-2012 models, while earlier numbers like P68023303AC are for 2008-2009 models. It is critical to match the part number exactly or use a VIN-based catalog when replacing the ABS module.

Diagnostic Flowchart

Other Known Issues on This Vehicle

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

• Front and Rear Subframe Corrosion 🔴 High — Extremely common, especially in salt-belt regions. Can become structurally unsafe, with control arms detaching in worst-case scenarios. (Ref: Chrysler issued an extended warranty (X01) for the 2007 model year front crossmember, but later years with the same issue were often not covered.)
• CVT Transmission Overheating and Failure 🔴 High → Shop Transmission Assembly — Common complaint, particularly on models with the Jatco JF011E CVT. Symptoms include whining noises, transmission overheat light, and sudden loss of power.
• Electronic Throttle Body Failure 🟠 Medium — A well-documented issue where the electronic throttle control (ETC) light (red lightning bolt) illuminates, putting the car into 'limp mode' with reduced power. Often caused by worn internal plastic gears.
• Premature Suspension Component Wear 🟠 Medium — Owners frequently report needing to replace lower control arms, ball joints, and tie rod ends sooner than expected, often due to rust and poor component quality.
• Sunroof Drain Tube Leaks 🟡 Low — The sunroof drain tubes are prone to clogging, causing water to leak into the cabin, potentially damaging the headliner and electronics in the A-pillar or fuse box area.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used wheel speed sensor is a reasonable choice if it can be tested or comes from a low-mileage vehicle from a dry climate. A used wiring harness pigtail is also a good option for repairing a damaged connector. A used ABS control module can be a cost-effective alternative to a new one, but it is CRITICAL to understand that it requires professional programming to your car's VIN to function.

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

What to inspect on the donor part:

• For Hubs: AVOID hubs from vehicles in the salt belt. Ask for clear photos of the sensor mounting area; if there is any visible rust flaking or the clip area looks degraded, reject the part.
• For Sensors: Inspect the plastic housing for any cracks or heat damage. Ensure the connector pins are clean and straight.
• For Modules: Match the part number EXACTLY. Inquire if the donor vehicle had any ABS-related codes before it was dismantled.

Aftermarket brands forum-validated for this vehicle:

• Hub Assemblies: Timken, SKF, and MOOG are consistently cited by mechanics and owners as premium, durable choices that often exceed OEM quality.
• Sensors: NTK (NGK), Delphi, and Standard Motor Products (SMP) are reputable brands for sensor electronics.

Brands owners have reported issues with on this vehicle:

• Hub Assemblies: Be cautious with unbranded, 'white-box' economy parts or brands with poor reviews, as some owners report extremely short service life (e.g., failure in under 1,000 miles).

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

• C0035 — Right front wheel speed sensor circuit fault; shares the same diagnostic path and susceptibility to road salt and debris as the rear sensors.
• C0040 — Right rear wheel speed sensor circuit fault; the right rear hub is equally prone to the same rust-related mounting clip failure as the left side (C0045).
• U0121 — Lost Communication with Anti-Lock Brake System (ABS) Control Module; related to the communication errors between ABS and PCM discussed in Dodge Caliber forum reports.
• C102B — Left Rear Wheel Speed Sensor Circuit; often appears alongside or instead of C0045 on Chrysler/Dodge platforms to indicate speed sensor signal issues.

Frequently Asked Questions