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Engine-Codes – Generic – P173B

P173B Code - CAN Engine Coolant Temperature Invalid

Quick Answer

The P173B diagnostic trouble code indicates that there is an issue with the Engine Coolant Temperature (ECT) signal on the Controller Area Network (CAN) bus. Common causes include Faulty Engine Coolant Temperature sensor, Wiring or connector issues in the ECT circuit, Malfunctioning ECM. 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
P173B indicates CAN Engine Coolant Temperature Invalid.
Common causes
Common causes include Faulty Engine Coolant Temperature sensor, Wiring or connector issues in the ECT circuit, Malfunctioning ECM.
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 07, 2024
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Code P173B Description

The P173B diagnostic trouble code indicates that there is an issue with the Engine Coolant Temperature (ECT) signal on the Controller Area Network (CAN) bus. The Engine Coolant Temperature sensor is responsible for monitoring the temperature of the engine coolant and sending this information to the engine control module (ECM) to ensure optimal engine performance. When the ECM receives an invalid or implausible signal from the ECT sensor via the CAN bus, it triggers the P173B code.

OBDII Code P173B - CAN Engine Coolant Temperature Invalid
P173B Code - CAN Engine Coolant Temperature Invalid

Common Causes of P173B

  1. Faulty Engine Coolant Temperature sensor
  2. Wiring or connector issues in the ECT circuit
  3. Malfunctioning ECM
  4. Communication errors on the CAN bus
  5. Low coolant level or coolant leak

Symptoms of P173B

  1. Engine overheating or running hot
  2. Poor fuel economy
  3. Rough idling or stalling
  4. Check Engine Light illuminated
  5. Decreased engine performance

How to Fix P173B

  1. Begin by conducting a visual inspection of the ECT sensor, wiring, and connectors for any obvious signs of damage or corrosion.
  2. Use a multimeter to test the ECT sensor's resistance and compare it to manufacturer specifications to determine if it is functioning correctly.
  3. Check the wiring harness for continuity and repair any breaks or shorts if necessary.
  4. Inspect the ECM for any faults or errors and reprogram or replace it as needed.
  5. Clear the trouble codes from the ECM and perform a test drive to ensure the issue has been resolved.

Cost to Fix P173B

The cost of repairing a P173B code can vary depending on the specific cause of the issue. In general, replacing a faulty Engine Coolant Temperature sensor can cost between $50 and $150, while repairing wiring issues or replacing the ECM can range from $100 to $500 or more. Labor costs typically amount to $80 to $150 per hour, and the total repair bill can add up to several hundred dollars. It is advisable to consult a professional mechanic for a more accurate estimate based on the specific circumstances of your vehicle.

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Code P173B Information for Specific Makes

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 P173B Code

1. What are the common symptoms of OBDII code P173B (CAN Engine Coolant Temperature Invalid)?

The common symptoms include inaccurate temperature readings on the dashboard, engine overheating, and potential issues with the vehicle's performance.

2. What are the possible causes of OBDII code P173B?

Potential causes of this code include a faulty engine coolant temperature sensor, wiring issues, a malfunctioning powertrain control module (PCM), or a problem with the Controller Area Network (CAN) communication system.

3. How can I diagnose the cause of OBDII code P173B?

To diagnose the issue, you can use an OBDII scanner to read the code and check the engine coolant temperature sensor's readings. Inspecting the wiring connections and the CAN system for any faults can also help pinpoint the cause.

4. Is it safe to continue driving with OBDII code P173B active?

It is not recommended to drive with this code active, as inaccurate engine coolant temperature readings can lead to engine overheating and potential damage. It's best to address the issue promptly.

5. Can I repair OBDII code P173B myself?

If you have experience with automotive repairs and diagnostics, you may be able to address this code by replacing the faulty engine coolant temperature sensor or repairing any wiring issues. However, consulting a professional mechanic is recommended for accurate diagnosis and repair.

6. Will resetting the fault codes make OBDII code P173B disappear?

Resetting the fault codes may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear. It's important to diagnose and fix the root cause of the problem.

7. How much does it typically cost to repair OBDII code P173B?

The cost of repairing this code can vary depending on the cause of the issue, the labor rates in your area, and the parts needed for the repair. It's advisable to obtain quotes from local mechanics or repair shops.

8. Can a bad engine coolant temperature sensor cause OBDII code P173B?

Yes, a malfunctioning engine coolant temperature sensor is a common cause of this code. If the sensor is providing incorrect temperature readings to the PCM, it can trigger the P173B fault code.

9. Are there any temporary solutions for OBDII code P173B?

While there may be temporary fixes such as resetting the fault codes, it's crucial to address the underlying issue causing the code for a long-term solution. Ignoring the problem can lead to more severe engine issues.

10. How long does it take to repair OBDII code P173B?

The repair time for this code can vary depending on the cause of the issue and the complexity of the repair. It could range from a quick sensor replacement to a more extensive diagnostic process to identify and fix wiring or PCM problems.

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