AftertreatmentCaterpillar Diesel ECM

SPN 3473 FMI 31

Name: ECM Performance
Address: Fort Lauderdale, FL, 33325, US
Telephone: (888) 768-2447
Price range: $$-$$$

DPF, DEF, SCR, and NOx-reduction system faults.

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System

Caterpillar Aftertreatment

Caterpillar ECM Service

Diagnostic Overview

CAT fault code 3473-31 commonly relates to an aftertreatment fuel or ARD system condition that is not meeting expected operation. The ECM may be unable to build the heat needed for a successful regeneration or may detect that the aftertreatment fuel delivery process is not correct. This can result in failed regens, increasing soot load, and eventual derate. Diagnosis should combine electrical checks, fuel supply checks, and temperature-rise verification.

Likely Causes

ARD fuel supply problem; plugged ARD nozzle; failed ignition or combustion; low fuel pressure; air supply issue; faulty temperature sensor; exhaust leak; failed regeneration.

What To Check First

Check ARD fuel delivery, inspect the nozzle and air supply, review regen attempts, and verify exhaust temperature rise during a commanded regeneration test.

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Related Aftertreatment Fault Codes

View All Aftertreatment Codes

SPN 1761 FMI 17

CAT fault code 1761-17 commonly relates to diesel exhaust fluid level or a DEF level signal that is below the expected range.

SPN 3360 / SPN 3820

CAT codes listed as 3360/3820 generally point toward the DEF supply, DEF quality, DEF tank, or SCR dosing system depending on the exact FMI shown in Cat ET.

SPN 3361 / SPN 3821

CAT codes listed as 3361/3821 commonly belong to the DEF dosing or SCR control side of the aftertreatment system.

SPN 3474 FMI 31

CAT fault code 3474-31 is typically associated with aftertreatment regeneration or ARD-related operation.

SPN 3701 FMI 15

CAT fault code 3701-15 commonly indicates an aftertreatment condition that is above normal but at a least-severe level, often connected with DPF soot load, regeneration need, or aftertreatment restriction.

SPN 3701 FMI 16

CAT fault code 3701-16 usually represents a more serious aftertreatment condition than 3701-15, with the measured or calculated value above normal at a moderate severity level.

View All Aftertreatment Codes →