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Fuel System fault codes

Tank to injector — lift pump and rail pressure, per-cylinder injector circuits and cylinder balance, water in fuel, and the filters in between. Rail-pressure faults in particular are far more often plumbing, air leaks, or a restricted filter than the expensive pump they get blamed on.

All 39 fuel system SPN/FMI and OBD codes in the knowledge base are listed below — each with what it means, how serious it is, the most-likely causes, and what to check first.

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Fuel System codes (39)

SPN 94 · FMI 1Serious

Fuel Delivery Pressure — Low

SPN 157 · FMI 18Serious

Injection Rail Pressure — Below Normal

SPN 97 · FMI 16Caution

Water in Fuel — Detected

SPN 157 · FMI 0Serious

Injector Metering Rail 1 Pressure - Data Valid But Above Normal Operating Range (XPI common rail fuel pressure too high)

SPN 157 · FMI 1Critical

Injector Metering Rail 1 Pressure - Data Valid But Below Normal Operating Range (XPI common rail fuel pressure too low)

SPN 651 · FMI 5Serious

Injector #1 open circuit

SPN 652 · FMI 5Serious

Injector #2 open circuit

SPN 653 · FMI 5Serious

Injector #3 open circuit

SPN 654 · FMI 5Serious

Injector #4 open circuit

SPN 655 · FMI 5Serious

Injector #5 open circuit

SPN 656 · FMI 5Serious

Injector #6 open circuit

P0087Serious

Fuel Rail/System Pressure Too Low

P0088Serious

Fuel Rail/System Pressure Too High

P0093Critical

Fuel System Leak Detected - Large Leak

P0094Serious

Fuel System Leak Detected - Small

P0171Serious

Fuel System Too Lean Bank 1

P0172Caution

Fuel System Too Rich Bank 1

P0174Serious

Fuel System Too Lean Bank 2

P0183Caution

Fuel Temperature Sensor A Circuit High

P0191Serious

Fuel Rail Pressure Sensor Circuit Range/Performance

P0192Serious

Fuel Rail Pressure Sensor Circuit Low

P0193Serious

Fuel Rail Pressure Sensor Circuit High

P0201Serious

Injector Circuit Open Cylinder 1

P0202Serious

Injector Circuit Open Cylinder 2

P0203Serious

Injector Circuit Open Cylinder 3

P0204Serious

Injector Circuit Open Cylinder 4

P0205Serious

Injector Circuit Open Cylinder 5

P0206Serious

Injector Circuit Open Cylinder 6

P0251Serious

Injection Pump Fuel Metering Control A

P0263Caution

Cylinder 1 Contribution/Balance Fault

P0266Serious

Cylinder 2 Contribution/Balance Fault

P0269Serious

Cylinder 3 Contribution/Balance Fault

P0272Serious

Cylinder 4 Contribution/Balance Fault

P0275Serious

Cylinder 5 Contribution/Balance Fault

P0278Serious

Cylinder 6 Contribution/Balance Fault

P1093Critical

HP Fuel Rail Pressure Low During Power Enrichment

P1096Serious

HP Fuel Rail Pressure High During Active Regen

P1131Caution

HO2S / Fuel Trim Lean — Bank 1 Sensor 1

P2BADCritical

High-Pressure Fuel System Relief Valve Open

Other systems

Aftertreatment & Emissions

100 codes

Drivetrain & Transmission

61 codes

Engine

58 codes

Brakes, ABS & Stability

41 codes

Electrical, Charging & Network

30 codes

Cooling, lubrication, HVAC and chassis/cab codes are listed on the fault code lookup, along with the search box that covers every code.

General diagnostic guidance for heavy-duty diesel equipment (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.