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Engine-Codes – Generic – C0045:18

C0045:18 Code - Left Rear Wheel Speed Sensor Circuit Low Signal Amplitude

Quick Answer

When the diagnostic trouble code C0045:18 appears, it indicates that there is a low signal amplitude in the left rear wheel speed sensor circuit. Common causes include Damaged or frayed wiring in the left rear wheel speed sensor circuit, Faulty left rear wheel speed sensor, Corrosion or debris affecting the sensor's connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
C0045:18 indicates Left Rear Wheel Speed Sensor Circuit Low Signal Amplitude.
Common causes
Common causes include Damaged or frayed wiring in the left rear wheel speed sensor circuit, Faulty left rear wheel speed sensor, Corrosion or debris affecting the sensor's connection.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 08, 2024
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Code C0045:18 Description

When the diagnostic trouble code C0045:18 appears, it indicates that there is a low signal amplitude in the left rear wheel speed sensor circuit. This sensor plays a crucial role in the vehicle's anti-lock braking system (ABS) and electronic stability control (ESC) system. The wheel speed sensor is responsible for monitoring the speed of the wheel and sending this data to the vehicle's control module.

OBDII Code C0045:18 - Left Rear Wheel Speed Sensor Circuit Low Signal Amplitude
C0045:18 Code - Left Rear Wheel Speed Sensor Circuit Low Signal Amplitude

Common Causes of C0045:18

  1. Damaged or frayed wiring in the left rear wheel speed sensor circuit
  2. Faulty left rear wheel speed sensor
  3. Corrosion or debris affecting the sensor's connection
  4. Malfunctioning ABS or ESC control module
  5. Issues with the vehicle's electrical system

Symptoms of C0045:18

  1. ABS warning light illuminated on the dashboard
  2. Traction control system malfunctioning
  3. ESC warning light activated
  4. Braking system feeling inconsistent or less responsive
  5. Vehicle experiencing difficulty maintaining stability during braking or cornering

How to Fix C0045:18

  1. Conduct a thorough inspection of the left rear wheel speed sensor circuit, including the wiring and connections.
  2. Test the left rear wheel speed sensor for proper functionality or replace it if necessary.
  3. Check and clean any corrosion or debris that may be affecting the sensor's connection.
  4. Inspect the ABS or ESC control module for any faults and address them accordingly.
  5. Clear the diagnostic trouble code and perform a test drive to ensure the issue has been resolved.

Cost to Fix C0045:18

The typical repair costs for addressing a C0045:18 code can vary depending on the extent of the issue and the specific repairs needed. In general, replacing a wheel speed sensor can cost between $100 and $200, while addressing wiring or control module issues may increase the overall cost. Factoring in parts and labor, the total repair cost could range from $200 to $500 or more. It is advisable to consult with a professional mechanic or auto repair shop to obtain an accurate estimate based on the vehicle's make and model, as well as any additional factors that may impact the repair process. Labor rates at auto repair shops can vary, so it is recommended to inquire about specific rates in your area for a more precise cost estimate.

What does this mean?

Tech Notes for C0045:18





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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C0045:18 Code

1. What are common symptoms of OBDII code C0045:18?

The common symptoms of OBDII code C0045:18 include the ABS warning light illuminated on the dashboard, potential loss of traction control functionality, and possible issues with the vehicle's stability control system.

2. What does the OBDII code C0045:18 indicate?

OBDII code C0045:18 indicates a low signal amplitude in the left rear wheel speed sensor circuit. This means that there is a problem with the signal coming from the sensor, affecting the detection of wheel speed by the vehicle's ABS system.

3. What are the possible causes of OBDII code C0045:18?

Possible causes of OBDII code C0045:18 include a faulty left rear wheel speed sensor, damaged wiring or connectors in the circuit, sensor alignment issues, or a malfunctioning ABS control module.

4. How can I diagnose the issue related to OBDII code C0045:18?

Diagnosing the issue related to OBDII code C0045:18 involves using a diagnostic scan tool to retrieve the code, checking the left rear wheel speed sensor for proper function, inspecting the wiring and connectors for damage, and testing the sensor's signal output.

5. Is it safe to drive with OBDII code C0045:18 present?

It is not recommended to drive with OBDII code C0045:18 present, as it can affect the proper functioning of the vehicle's ABS system, traction control, and stability control. It is best to address the issue promptly to ensure safe driving conditions.

6. How can I repair OBDII code C0045:18?

Repairing OBDII code C0045:18 involves addressing the root cause of the issue, which may include replacing the left rear wheel speed sensor, repairing damaged wiring or connectors, realigning the sensor, or addressing any ABS control module malfunctions.

7. Can OBDII code C0045:18 be triggered by other issues besides the wheel speed sensor?

While OBDII code C0045:18 is specifically related to the left rear wheel speed sensor circuit, other issues such as damaged wiring, sensor alignment problems, or ABS module malfunctions can also trigger this code.

8. How important is it to fix OBDII code C0045:18 promptly?

It is important to fix OBDII code C0045:18 promptly to ensure the proper functioning of the vehicle's ABS system, traction control, and stability control. Ignoring this issue can compromise the safety and stability of the vehicle during driving.

9. Can I reset the OBDII code C0045:18 without addressing the underlying issue?

While you can clear the OBDII code C0045:18 using a diagnostic scan tool, it is crucial to address the underlying issue causing the code to prevent it from reoccurring and ensure the proper functioning of the ABS system.

10. How can a professional mechanic help in resolving OBDII code C0045:18?

A professional mechanic can use advanced diagnostic tools and expertise to accurately diagnose the issue related to OBDII code C0045:18, perform necessary repairs or replacements, and ensure that the ABS system is functioning correctly.

Discuss the causes and fixes for C0045:18 OBDII Code

Submit a New Comment

  • Changed hub and sensor now the output is possible a bad pigtail?

    Reply to Comment

    • Yes, definitely possible. If you’ve already replaced the wheel hub and sensor, and you’re still getting C0045:18 (low signal amplitude), the next thing I’d check is the pigtail (sensor connector and wiring).

      Here’s what to look for:

      1. Bent pins or loose fit – Make sure the connector seats tightly on the sensor and that none of the pins are pushed back or corroded.

      2. Wiring damage – Flex the wire while watching the scanner or multimeter. These wires can break inside the insulation near the wheel well or where they enter the body harness.

      3. Continuity and voltage – With key ON, you should see a reference voltage (usually 5–12V depending on the system), and the ground should be solid. Spin the wheel and look for a signal drop or change if you have access to a scope.

      If everything else is new, a weak or broken wire in the pigtail is a likely suspect. You can buy replacement pigtails or repair kits if needed.

      Let me know what vehicle this is and I can guide you on pinout or test values.

      Reply to Comment