The SPN Reference section of J1939 Hub provides a comprehensive index of SAE J1939 Suspect Parameter Numbers (SPNs). Each SPN entry documents the parameter definition, engineering unit, valid data range, and all associated Failure Mode Identifiers (FMIs) with direct links to their individual diagnostic guides. Coverage spans all J1939-compliant systems including diesel engines, aftertreatment, transmission, brakes, chassis, electrical, hybrid and electric drivetrains, agricultural implements, construction equipment, and marine propulsion. Use this reference to identify any SPN in the SAE J1939DA standard and navigate directly to the specific fault code combination you are diagnosing.
The Suspect Parameter Number (SPN) 806, also known as “Dif 1 – ASR Valve,” is an integral part of the vehicle’s Anti-Slip Regulation (ASR) system, commonly found in commercial trucks and heavy-duty machinery. This parameter monitors the operation of the ASR valve, a component critical for maintaining traction by modulating brake pressure and engine torque. … Read more
Tire 17 Pressure, identified as Suspect Parameter Number (SPN) 7129, is a diagnostic parameter used within the SAE J1939 network to monitor the inflation pressure of the seventeenth tire position on heavy-duty vehicles and equipment. This parameter is part of a broader Tire Pressure Monitoring System (TPMS) and is critical for maintaining vehicle stability, fuel … Read more
SPN 6992, labeled Engine Cylinder 1 Exclude from Combustion Request, is a SAE J1939 control parameter that allows an external system or controller to command the engine ECU to deliberately skip cylinder 1 from participating in the combustion cycle. Unlike fault-driven cylinder deactivation, this parameter represents an intentional, commanded exclusion — a calibration or operational … Read more
The PEMS Engine Fuel Mass Flow Rate, identified by the SAE J1939 Suspect Parameter Number (SPN) 6893, is a critical diagnostic and operational parameter in heavy-duty diesel engines. This SPN monitors the mass of fuel consumed by the engine per unit of time, expressed in grams per second. It is vital for various vehicle systems, … Read more
The Suspect Parameter Number (SPN) 5891, labeled “Transmission Pressure Switch 1,” is a critical diagnostic parameter used to monitor the state of the first pressure switch within an automatic transmission. This SPN is not a direct measurement of fluid pressure but rather a discrete digital signal indicating whether a specific clutch, brake, or hydraulic circuit … Read more
SPN 5714 monitors the self-diagnosis status of the first NOx sensor positioned at the intake of the aftertreatment system on Engine Exhaust Bank 1 (EEB1). This parameter reports whether the NOx sensor’s internal diagnostic routine is idle, actively running, completed, aborted, or unable to execute — providing the engine control module (ECM) and aftertreatment control … Read more
The Suspect Parameter Number (SPN) 5418, labeled as “Engine Fuel Actuator 1,” plays a critical role in monitoring and controlling the flow of fuel to an engine. This parameter is integral to ensuring optimal engine performance and efficiency across various heavy-duty vehicle systems. It is frequently found in engines by leading manufacturers such as Cummins, … Read more
SPN 524279 is a Manufacturer Assignable SPN, as defined by the SAE J1939-73 standard. This parameter number resides in a reserved range (524288–526335) that original equipment manufacturers (OEMs) are permitted to map to proprietary sensors, actuators, or internal control logic not covered by standardized SPNs. In practice, SPN 524279 is used by various heavy-duty powertrain … Read more
SPN 524251 falls within the manufacturer-assignable SPN range defined by the SAE J1939 standard, meaning its specific function, scaling, and diagnostic behavior are determined entirely by the original equipment manufacturer (OEM) rather than by a globally standardized definition. This category of SPNs is intentionally reserved so that engine and vehicle manufacturers — including Cummins, Detroit … Read more
The SAE J1939 Suspect Parameter Number (SPN) 52353 is a crucial diagnostic parameter used across various heavy-duty vehicle systems. While specifics about SPN 52353 such as its label, description, and parameter group are not readily available, SPNs like this play a vital role in monitoring and diagnosing vehicle and engine performance. SPN 52353 is typically … Read more