DERATE — truck fault codes

app.deratePublished by derate.appOfficial publisherv2.0.0Updated Oct 24, 2026

Heavy-duty truck SPN/FMI and OBD fault codes: meaning, safe-to-drive verdict, parts and recalls.

VerifiedStreamable HTTPWeb executableLocation & LifestyleKnowledge & Memory

Overview

AI-generated overview

A remote MCP server that lets an assistant look up heavy-truck fault codes, safe-to-drive verdicts, parts, recalls and DERATE guides.

What you can do
Look up and explain truck fault codes by SPN/FMI, P-code or symptom, with severity, causes, tests and cost estimates, and list codes in a demo diagnosis or the supported engine families and protocols. Get a safe-to-drive verdict for a code and plain-language interpretation of derates or power loss. Search the fault-code library and DERATE guides and news, and read a full guide by slug. Retrieve recall-check guidance, dataset notes, pricing, app download links and a full demo diagnosis.
When to use it
Useful when a driver, mechanic or fleet assistant needs to interpret a diesel truck fault code or derate symptom, judge whether driving on is safe, or find DERATE's published guides, recall guidance and pricing.
Requirements
A remote streamable HTTP endpoint at derate.app; no authentication, environment variables or headers are declared. The DERATE app itself is a mobile app for iOS and Android.
Before you install
Diagnostic output is informational and limited to DERATE's library; unknown codes return 'unknown'. Paid plans are purchased inside the mobile app, so pricing lookups may lead to spending. Recall guidance is NHTSA-based and links out to per-make sources.

Installation

In SourceWeft

  1. Open DERATE — truck fault codes in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/app.derate%2Fderate/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "derate-truck-fault-codes": {
      "type": "http",
      "url": "https://derate.app/mcp"
    }
  }
}

Tools

15

buscar_codigo

Search truck fault code / Buscar código

Search DERATE's 56-code heavy-truck library by SPN/FMI, P-code or free text. Returns severity, derates yes/no, meaning, part and estimated part-price range, and the page URL. / Busca en la biblioteca de códigos de DERATE.

Parameterslangqueryrequired

es_seguro_manejar

Is it safe to drive? / ¿Es seguro manejar?

Safe-to-drive verdict (stop / service_soon / info) for a truck fault code, from DERATE's library only. Unknown codes return 'unknown'. / Veredicto de si es seguro seguir manejando.

Parameterscoderequiredlang

retiros_de_camion

Truck recalls / Retiros de camión

How to check heavy-truck safety recalls (NHTSA-based), with per-make source links for Freightliner, Volvo, Kenworth, Peterbilt, International, Mack and Western Star. / Cómo revisar retiros de seguridad.

Parameterslangmakelimitquery

get_data_notes

Data quality notes / Notas de calidad de datos

DERATE dataset notes: code count, sources, known gaps, license (CC BY 4.0), how to cite and download URLs. / Notas de calidad, licencia y cómo citar.

Parameterslang

search_guides

Search guides and news / Buscar guías y noticias

Search DERATE's truck-driver guides and trucking news (derate, DEF, emissions, recalls, enforcement, market). Returns title, quick answer and derate.app URL. / Busca en las guías y noticias de DERATE.

Parameterslangqueryrequired

get_guide

Get a guide or news article / Ver guía o noticia

Full text (markdown) of one DERATE guide or news article by slug, with sources and the derate.app URL to cite. / Texto completo de una guía o noticia.

Parameterslangslugrequired

get_truck_fault_code

Get truck fault code

Look up a diesel truck fault code (J1939 SPN/FMI such as 'SPN 3251 FMI 0', or an OBD-II code such as 'P2002') in DERATE's public fault-code library. Returns what the code means, its severity, whether it is safe to keep driving, probable causes, the recommended tests, and the canonical URL of the public page for that code. Works without any account.

Parameterscoderequiredlangengine_family

interpret_derate

Interpret an engine derate

Explain a diesel truck engine derate or power-loss symptom described in plain language (for example 'DEF light on and truck limited to 55 mph'). Returns the most likely cause, how urgent it is, the immediate action to take, and matching public fault-code pages. This is the free public interpretation; the full guided diagnosis with tests and a work order runs in the DERATE app.

Parameterscodelangsymptomrequiredengine_family

search_fault_code_library

Search the fault code library

Full-text search over DERATE's public diesel truck fault-code library by code, system, dashboard light or symptom words. Returns a list of matching entries with code, title, severity, system and the canonical public URL.

Parameterslanglimitqueryrequiredseverity

list_supported_engine_families

List supported engine families

List the diesel truck engine families and code protocols DERATE interprets (J1939 SPN/FMI and OBD-II), so an agent knows whether a given truck is covered before looking up a code.

Takes no parameters.

get_pricing

Get DERATE pricing

List DERATE's plans and prices in USD. The app is a free download; plans are purchased inside the iOS/Android app (App Store / Google Play). Monthly Driver and Shop plans include a 7-day free trial for new subscribers.

Takes no parameters.

get_diagnosis

Get diagnosis

Return the full DERATE demo diagnosis for a truck: verdict (STOP/CAUTION/CLEAR), derate countdown, every fault code and the work order summary.

Parameterslang

list_fault_codes

List fault codes

List the fault codes (SPN/FMI) in the current DERATE diagnosis with severity, system, fault type and whether they are a root cause.

Parameterslang

explain_fault_code

Explain fault code

Explain a truck fault code or symptom in DERATE terms: plain-language meaning, severity, probable causes, recommended tests with expected values, repair steps and cost estimate.

Parameterslangqueryrequired

Version history

1
  1. v2.0.0LatestOct 10, 2026

Score

83% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts

    Declare a GitHub repository with a README, or serve resource_documentation in the OAuth protected-resource metadata.

  • LicenseNot applicable

    A hosted service is used under its provider's terms, so no license is expected here. This check is left out of the percentage.