Fault code details

Quickly discover what those dash lights mean and know what caused the problem.

Live data monitoring

Viewing live data keeps you informed about your vehicle at any moment.

Bi-directional commands

Reset fault codes, reset aftertreatment, forced DPF regen

Instant fault code insights for Paccar MX engines

  • Understand your Check Engine Light: Quickly understand what those active fault codes mean with detailed information to help you know what is going on.
  • Identify the cause and take action: Get detailed explanations of fault codes specific to Paccar MX engines. You can use this information know what to do and how to proceed.
  • Track how many times they that fault occurred: You will see the count and be able to use that information to track if this is the first time this issue is coming on or it's an ongoing issue.
  • It doesn't just cover your engine: You will notice we cover transmission, abs, chassis, cab & body as well. We try to report to you everything that is going on with your vehicle.
Learn More about fault codes

Monitor real-time data engine parameters

What you can monitor:

  • Intake pressure (turbo boost): Monitor turbocharger performance to gauge how your engine responds under various load conditions.
  • DPF soot and ash levels: Monitor the accumulation of soot and ash to determine the optimal times for DPF regen, helping prevent DPF derates.
  • DEF fluid level: Keep track of Diesel Exhaust Fluid levels.
  • EGR valve position: Track the position of the Exhaust Gas Recirculation valve.
  • Exhaust and DPF temperatures: Observe temperatures to manage the DPF Regen process effectively.
  • SCR temperatures: Keep an eye on Selective Catalytic Reduction temperatures to ensure NOx reduction.
  • Engine mileage & hours: Track engine hours and other vital diagnostics.
  • + more: We go even beyond this list. Our goal is to supply you with data to help you monitor your vehicle in real time.
Learn More about live data

Paccar MX | Years and engines covered

Reset fault codes

Resetting fault codes: The reset of fault codes covers both active and Inactive codes.

  • Active codes: These are alerts for current issues that need immediate attention.
  • Inactive codes: These are records of past problems. They’re helpful for spotting patterns or issues that might come back again.
  • Reset all modules: We perform the reset on all the available modules that we are connected to, including transmission, body, cab & chassis systems. 

Importance of resetting codes: Clearing these codes after you fix an issue keeps the diagnostic system focused only on what’s currently active. This is crucial for verifying that repairs were successful and for maintaining accurate, up-to-date vehicle diagnostics.

Reset DEF derate

Resetting DEF derate for fault codes P1518 and P151A

When fault codes P1518 or P151A trigger a 5mph derate on your vehicle, certain steps need to be taken to address Diesel Exhaust Fluid (DEF) derate.

This process helps eliminate the reduced speed limitation and restores normal vehicle operation, ensuring your engine performs efficiently under regulatory compliance.

Reset EGR Derate

Disabling EGR derate for fault codes P1495 and P1496

When experiencing power derate due to EGR (Exhaust Gas Recirculation) issues signaled by fault codes P1495 or P1496, you can reset this condition.

Using Reset EGR Derate you can effectively disable the EGR derate, restoring your vehicle’s power and performance.

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Purge SCR/DEF module

When you repair the Emission Aftertreatment System (EAS) in a vehicle, it’s important to use the reset function on the system’s Electronic Control Unit (ECU).

This function is crucial because the ECU keeps a record of all complete and incomplete after-run purges of the SCR (Selective Catalytic Reduction) / DEF (Diesel Exhaust Fluid) pump module.

Resetting the ECU after repairs helps clear these records and ensures that the system starts fresh, which is vital for maintaining accurate data for future diagnostics and ensuring the emission system operates effectively.

This reset helps optimize the performance and efficiency of the repaired emission control components, ensuring they function as intended.

Install a cleaned DPF

When a cleaned Diesel Particulate Filter (DPF) is reinstalled in a vehicle, it's critical to reset the ash level recorded in the aftertreatment Electronic Control Unit (ECU).

Key steps to reset the ash level:

  • Initiate the reset test procedure: This action requests the aftertreatment ECU to clear any previous ash accumulation data.
  • ECU adjustment: The aftertreatment ECU resets its internal ash level to zero, acknowledging the DPF has been cleaned and reinstalled.

Importance of resetting ash levels:

  • Maintain DPF efficiency: Resetting the ash level ensures that the DPF operates at optimal efficiency, free from past contamination data.
  • Prevent false maintenance alerts: Accurate ash level readings prevent unnecessary maintenance alerts and ensure the vehicle’s emission system is correctly evaluated.
  • Extend DPF lifespan: Proper maintenance and resetting of ash levels contribute to extending the life of the DPF, promoting better fuel economy and reduced emissions.

Install a new DPF

When installing a new Diesel Particulate Filter (DPF), a degreening process is necessary to effectively burn off the excess residue from the catalytic coating.


  • Ensures the new DPF functions efficiently and without disruptions from manufacturing residues.
  • Maintains overall vehicle performance and compliance with emission standards.

By initiating this, you ensure that the new DPF integrates smoothly into the vehicle's emission system.

Forced DPF regen

The Diesel Particulate Filter (DPF) captures soot during engine operation. To clear this soot, the DPF periodically undergoes active or passive regen, usually automatically, while the engine runs.

When to use:

  • Fault codes: Some fault codes require you to run a forced DPF regen in order for certain fault codes to clear. This is because the emission system wants to run through all the system checks before the fault codes is cleared.
  • Driving conditions: If regular driving doesn't achieve the engine load and temperature necessary for active regen, then a forced DPF regen becomes essential. This is often required in situations involving excessive idling or operations under light loads.
  • High soot: If soot accumulation surpasses what normal regeneration can handle, a forced DPF regen is necessary to prevent blockages.


  • Ensures efficiency & reliability: It maintains the DPF’s effectiveness and extends its lifespan.

Nexiq Blue-Link 2 hardware

  • Unlock the full potential of your truck's diagnostics system with Nexiq Blue-Link 2 hardware.
  • Designed for seamless integration with the trucks we support, this device connects via Bluetooth, ensuring robust and reliable data transmission without the hassle of wires.
Learn more about hardware
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This product paid for itself on the first use. Easy to use and understand, and prevents small problems from turning into bigger problems. My favorite feature is the "Live Data". OTR Performance is a must have for any smart O/O or small fleet who wants to save time and money.
— Robert Purser - Google Review
Money well spent!! Their customer service is excellent and the diagnostic subscription is gonna save you money. Thoroughly impressed! Just imagine being able to get to a shop after you disable the derate that has you stuck on the shoulder of the highway, needing a tow for thousands.
— Calcasola - Google Review
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OTR Diagnostics FAQs

How do I purchase to get started?

1. Purchase Your Package:

  • Select the quantity of vehicles and purchase the Professional Package to ensure you have everything you need.

2. Account Activation:

  • Check your email for an activation link. Use the same email address that you used for your purchase to activate your account.

3. Download the App:

  • Download the 'OTR Diagnostics' app from the Apple App Store or Google Play Store. Log in using the credentials you created during registration.

4. Need Help?

  • If you encounter any issues, feel free to reach out via email, chat, or call us at 586-799-4375.

Please note: Your OTR Diagnostics Subscription is linked to the email address used during the purchase process.

How does the subscription work?

Subscriptions are based on a 12-month auto-renew basis.

Does this app need to be online to be used?

OTR Diagnostics is bluetooth based and does require you to have Wifi or Cellular coverage for you to be able to use the app.

We do have an offline mode as a feature which does require you to have internet upon first login with the adapter connected for this to function.

It is recommended to use OTR Diagnostics with internet connected to ensure properly functionality.

Which platforms is OTR Diagnostics available for?

OTR Diagnostics works on iOS and Android mobile phones and tablets.

What does the limited lifetime warranty include?

Our OTR Diagnostics hardware is backed by a Limited Lifetime Warranty, which is a testament to our commitment to your satisfaction.

Warranty Coverage: Our Limited Lifetime Warranty covers material and manufacturing defects in our OTR Diagnostics hardware for as long as you maintain an active subscription to OTR Diagnostics. We understand that your investment in our product is significant, and we want you to be confident that it will perform as designed.

For a complete understanding of our warranty terms and conditions, please refer to the terms and conditions.

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