The structure of a fault code
A code has structure even when its definition is proprietary. The second character is the one that matters.
Code structure
A fault code such as P0301 reads in four parts: a letter for the system group (P powertrain, B body, C chassis, U network), a digit for who defined it (0 the industry standard, 1 the manufacturer), a digit for the subsystem and two digits for the fault, so P0301 is a standard powertrain code for a cylinder 1 misfire in the ignition subsystem. P0 codes are commonly standardized and P1 codes manufacturer-defined.
- Other second-digit ranges also exist
- Confirm the complete code against the applicable standard and the model’s service information. Many side-by-sides skip this format and show a Polaris-style SPN and FMI pair instead.
The structure, character by character
| Position | What it identifies | Common values |
|---|---|---|
| First, letter | System group | P powertrain · B body · C chassis · U network communication |
| Second, digit | Who defined it | 0 generic, defined by the standard · 1 manufacturer-defined |
| Third, digit | Subsystem within the group | Fuel and air metering, ignition, emissions controls, speed and idle control, and so on |
| Fourth and fifth | The specific fault within that subsystem | A two-digit number, meaningful only in combination with the rest |
Why a generic definition can still mislead you
Even a generic code carries an assumption about the vehicle it was written for, and that assumption is a car. A code whose generic definition names a component in a layout typical of a four-cylinder car engine may be triggered on a machine by a structurally similar but physically different circuit. The name is right in kind and misleading in detail.
The second problem is scope. Many machines set manufacturer-defined codes for conditions that a car would report generically, simply because the manufacturer chose to. Reading a manufacturer code against a generic table produces a definition that belongs to a different fault entirely, which is one of the most common ways a home diagnosis goes wrong.
Side-by-sides: SPN and FMI instead of P-codes
Polaris owner's manuals list each code the dash can show under "Diagnostic Display Code Definitions", with a condition name and an SPN and FMI pair, for example a throttle body control position deviation fault.
The SPN (suspect parameter number) names the signal and the FMI (failure mode identifier) says how it failed, using the SAE J1939 list: FMI 3 is voltage above normal or shorted high, 4 voltage below normal or shorted low, 5 current below normal or an open circuit, 6 a grounded circuit, 7 a mechanical system not responding, 2 erratic or intermittent data, 0 and 1 data valid but above or below the normal range, and 31 a condition that exists.
On a Can-Am the codes do not appear on the dash on their own; they are read by following a set sequence on the display or with BRP's BUDS2 dealer tool. In every case the machine's own code list defines the number.
Pending, stored and permanent
Systems commonly distinguish between a fault that has been seen once and one that has been confirmed. A pending code has been detected but has not yet met the criteria for the system to commit to it, often meaning it needs to occur on a second drive cycle. A stored or confirmed code has met those criteria and normally illuminates the warning lamp.
A pending code with no lamp is early notice of an intermittent fault, and tools differ in whether they show pending codes at all.
Codes that arrive in groups
Several faults can share a supply, ground or communication problem. Confirm the electrical conditions before assuming that each code identifies a separate failed component.
The productive move with a group of codes is to look for what they have in common: a shared power feed, a shared ground, a shared connector, a shared harness route past something that chafes.
References
- Manufacturer Diagnostic display code definitions: each displayed code with its condition and SPN and FMI values: Polaris.
- Research Failure mode identifier (FMI) codes on the J1939 data link: FCAR Tech USA.
- Research Can-Am fault code list: how to read and clear them: PowerSportsGuide.
Reading a fault code questions
What does the P in P0301 mean?
It identifies the system group: P for powertrain, B for body, C for chassis and U for network communication faults. It is the broadest classification in the code and it tells you which part of the machine the control system was looking at when the fault was recorded.
What is the difference between a P0 and a P1 code?
The second character says who defined the code. A zero means the definition comes from the industry standard and is the same on every vehicle implementing it. A one means the manufacturer defined it, and no generic database knows what it means. Looking up a manufacturer code in a generic table gives you a definition belonging to a different fault entirely.
Can I trust a generic code definition on a motorcycle?
Partly. A generic definition is correct in kind but was written with a car in mind. So the component it names may correspond to a structurally similar but physically different circuit on your machine. Treat it as a strong hint about the subsystem, not as a literal description of the part.
What is a pending code?
A fault the system has detected but not yet confirmed, usually because it needs to occur again on a subsequent drive cycle before the system commits to it. A pending code with no warning light is early notice of an intermittent problem, which is a considerably better position than finding it once it has become permanent.
Why did several codes appear at once?
Almost always one shared cause, not several independent faults. Low system voltage, a failed ground, a disconnected multi-way connector or water in a harness can put many circuits out of range simultaneously. Look for what the codes have in common, a shared feed, ground, connector or harness route, instead of working through them in order.
What does the third character in a code tell me?
It identifies a subsystem within the group: fuel and air metering, ignition, emissions controls, speed and idle control, and so on. On its own it is coarse information, but combined with knowing whether the definition is generic or manufacturer-specific it narrows where to look before you have any definition at all.
Do U codes mean the machine has an electrical fault?
U codes concern network communication: one module not hearing from another, or a bus problem. That can be a wiring or connector fault, a module that has lost power, or a module that has failed. On a machine with several control units, a U code is often the first symptom of a supply or ground problem, not a network fault as such.
How many times does a fault have to occur before it stores?
It depends on the manufacturer’s strategy for that specific fault, and it is not standardized. Some faults store immediately because they are serious; others require confirmation across multiple drive cycles to avoid false alarms. Pending versus stored is the visible part of that strategy.
What is a permanent code?
On systems that implement it, a permanent code is one that cannot be cleared with a tool and only clears itself once the system has verified across several operating cycles that the fault is gone. It exists to stop a fault being hidden by clearing codes before an inspection. Its presence means the machine is not yet satisfied the problem is fixed.
Is a misfire code always a spark problem?
No. A misfire code reports that combustion did not happen properly in a cylinder. The causes include ignition, fuel delivery, compression, and even a mechanical fault such as a valve not sealing. The code names the symptom, not the cause. Parts-swapping gets expensive exactly there.
Should I fix codes in the order the tool lists them?
No. Tools typically list codes in numerical or chronological order. Neither reflects diagnostic priority. Deal with power supply and ground issues first, then network communication faults, then the specific circuit faults, because the first two generate the third, and fixing them often clears most of the list.
Where can I look up my manufacturer specific codes?
In the service information for your exact model and year, from the manufacturer, a dealer, or a subscription service that licenses it. Generic databases do not contain them, and lists circulating on forums are unverifiable and frequently taken from a different model year. The exact year matters because definitions change within a nameplate.
Where the figures and rules come from
- Standard
- Diagnostic Trouble Code Definitions : SAE International, SAE J2012; Standard; E/E Diagnostic Test Modes : SAE International, SAE J1979; Manufacturer; Diagnostic display code definitions: each displayed code with its condition and SPN and FMI values : Polaris. Checked 2026-09-30. Rechecked annual.
- Diagnostic connectors: getting the code out at all
- What connector you have, and what a generic scan tool can read from it.
Blink codes and warning lights; Counting flashes, and what a warning lamp is and is not telling you.
- Fault codes: the diagnostic order that works
- Cheap and physical first, expensive and electronic last.
Batteries and charging, behind a group of unrelated codes; Supply voltage and grounds put many circuits out of range at once.