Truck Fault Codes

PACCAR Fault Code Context

PACCAR fault-code context can vary across vehicle, engine, aftertreatment, and chassis modules, so official service information is needed before repair decisions. This hub does not claim to replace official OEM service information or diagnostic software.

Review status: source-backed medium Last reviewed: 2026-04-03

PACCAR Brands, Engines, and Diagnostic Tools

PACCAR Inc. manufactures Kenworth and Peterbilt trucks for North America (and DAF trucks for Europe). The PACCAR MX-13 and MX-11 are PACCAR-designed engines used in premium-spec Kenworth T680/T880 and Peterbilt 579/567 trucks. PACCAR also sells trucks with Cummins X15 engines, and some configurations use other powertrain suppliers. The engine installed determines which diagnostic software and service documentation applies.

PACCAR ESA (Electronic Service Analyst) is the OEM diagnostic tool for Kenworth and Peterbilt vehicles with PACCAR MX engines. It provides engine, aftertreatment, chassis, and cab diagnostics. For vehicles with Cummins engines, Cummins Insite covers the engine side while PACCAR ESA covers the chassis and cab modules. DAVIE is the equivalent tool for DAF trucks in Europe.

PACCAR MX Engine Fault Code Specifics

The PACCAR MX-13 and MX-11 are common-rail diesel engines designed for North American regulatory requirements. They use a combined DPF and SCR aftertreatment system with DEF injection and NOx sensor monitoring. Fault codes from MX engines use J1939 SPN/FMI conventions, accessible through PACCAR ESA for full diagnostic depth.

PACCAR MX engines have undergone several calibration generations since their introduction, aligned with GHG14 and GHG17 emissions requirements. The aftertreatment inducement thresholds, SCR monitoring parameters, and reset procedures differ between calibration levels. Engine serial number and model year are required context before consulting any fault code reference for the MX-13 or MX-11.

Chassis and Cab Codes on Kenworth and Peterbilt

Kenworth and Peterbilt trucks generate fault codes from multiple J1939 source addresses: the engine ECM, aftertreatment module, ABS controller (typically Bendix or WABCO), transmission (Eaton or Allison), and chassis body controller. The driver display may show codes from any of these modules using the same dashboard format, making source address identification important for routing the fault to the correct diagnostic system.

PACCAR cab and chassis codes — from body controllers, instrument clusters, or HVAC systems — require PACCAR ESA or PACCAR-specific documentation. These codes are distinct from engine and drivetrain codes and follow PACCAR's own fault code structure rather than the J1939 SPN/FMI framework used by engine suppliers.

Using This Site for PACCAR Fault Code Context

Fault code pages on this site that reference PACCAR MX-13 or MX-11 engines use NHTSA technical service bulletins and SAE J1939 references as the primary source basis, as PACCAR's proprietary service information requires ESA access and dealer-level authorization. These pages explain the diagnostic category and common causes for high-frequency codes rather than reproducing PACCAR's proprietary procedures.

For Kenworth or Peterbilt trucks with Cummins engines, the Cummins fault code pages on this site are more directly applicable than the PACCAR-specific pages. For chassis-level codes from Kenworth or Peterbilt body controllers, PACCAR ESA and authorized service documentation are the appropriate references.

Fault Code Coverage on This Site

PACCAR engine coverage spans the MX-13 (12.9-liter, used in Kenworth T680/T880 and Peterbilt 579) and MX-11 (10.8-liter, lighter-duty Kenworth and Peterbilt applications). Engine performance and protection fault categories covered for the MX-13 include: SPN 94 FMI 1 (fuel delivery pressure low); SPN 100 FMI 1 (engine oil pressure low, MX-13); SPN 102 FMI 17 (boost pressure low); SPN 110 FMI 0 (coolant temperature high); SPN 157 FMI 18 (fuel rail pressure low); SPN 175 FMI 0 (engine oil temperature high); and SPN 190 FMI 0 (overspeed event, MX-13). MX-11 coverage includes SPN 94 FMI 1 (fuel delivery pressure low) as a shared fault category.

Aftertreatment fault categories covered for the MX-13 include: SPN 3055 FMI 14 (parked regeneration required); SPN 3251 FMI 0 (DPF differential pressure high); SPN 3480 FMI 0 (NOx sensor outlet reading high); SPN 5246 FMI 31 (SCR efficiency below threshold); and SPN 1569 FMI 31 (engine protection torque derate active, MX-13 and MX-11). All PACCAR pages on this site reference NHTSA PACCAR service support publications and the SAE J1939 standard.

Related Pages

Related Fault Code Pages

Official Resources

  • Kenworth Dealer Service Resources — PACCAR / Kenworth dealer service portal for T680, T880, and related model service information. PACCAR ESA (Electronic Service Analyst) is the OEM diagnostic tool for MX-13 and MX-11 engines.
  • PACCAR Inc. — Commercial Vehicle Technology — PACCAR corporate portal covering Kenworth and Peterbilt vehicle brands and the PACCAR MX engine product line.

Sources

  • PACCAR Engine Technical Services PACCAR Inc. · oem · accessed 2026-06-10 · confidence medium

    Source: PACCAR Inc., PACCAR Engine Technical Services. This page paraphrases factual fields only and is not a substitute for the original document.

    Open source
  • SAE J1939 Standards Collection SAE International · official · accessed 2026-05-05 · confidence medium

    Source: SAE International, SAE J1939 Standards Collection. This page paraphrases factual fields only and is not a substitute for the original document.

    Open source

FAQ

Do Kenworth and Peterbilt use the same fault-code system since both are PACCAR brands?

Kenworth and Peterbilt share PACCAR platform architecture, so chassis-level fault codes and PACCAR MX engine codes use the same system and diagnostic tool (DAVIE or PACCAR ESA). However, cab configurations, dashboard display formats, and option-specific modules can differ between the two brands in ways that affect how codes appear to the driver.

If a Kenworth has a Cummins engine, whose fault code system applies?

The engine fault codes (from the engine ECM) are Cummins-specific and require Cummins Insite. The chassis, cab, and PACCAR-specific module codes use DAVIE or PACCAR ESA. A Kenworth T680 with a Cummins X15 will show Cummins SPN/FMI codes from the engine and PACCAR chassis codes from body and cab modules — the source address distinguishes them.

What is the difference between DAVIE and PACCAR ESA for fault-code diagnosis?

DAVIE is used primarily for DAF trucks (PACCAR's European brand). PACCAR ESA (Electronic Service Analyst) is the tool used for Kenworth and Peterbilt in North America. ESA covers PACCAR MX-11 and MX-13 engine diagnostics, chassis modules, and vehicle-level systems on current KW and Pete models.

Which PACCAR engine models and fault codes are covered on this site?

Coverage spans the PACCAR MX-13 (Kenworth T680, T880, Peterbilt 579) and MX-11 (Kenworth T270/T370, Peterbilt 220/330) platforms. MX-13 covered SPNs include: SPN 94 FMI 1 (fuel delivery pressure low), SPN 100 FMI 1 (oil pressure critically low), SPN 102 FMI 1 (boost pressure below normal), SPN 110 FMI 0 (coolant temperature high), SPN 157 FMI 18 (fuel rail pressure low), SPN 175 FMI 0 (oil temperature high), SPN 190 FMI 0 (engine overspeed), SPN 3055 FMI 14 (DPF regen inhibited), SPN 3251 FMI 0 (DPF restriction), SPN 3480 FMI 5 (exhaust brake actuator fault), SPN 5246 FMI 31 (SCR efficiency below threshold), and SPN 1569 FMI 31 (aftertreatment inducement derate). The MX-11 is covered for SPN 94 FMI 1 and SPN 1569 FMI 31. All MX-series pages reference DAVIE4 and PACCAR ESA as the diagnostic tool paths.