Cummins fault code · SCR catalyst and inducement

Cummins fault code 3164

SCR Intake Temperature: reading above normal (least severe)

J1939 SPN4360
FMI15
LampNo lamp
SystemSCR catalyst and inducement

What it means

Cummins' description: Aftertreatment 1 SCR Intake Temperature - Data Valid But Above Normal Operating Range - Least Severe.

SPN 4360 is Aftertreatment 1 SCR Catalyst Intake Gas Temperature. FMI 15 means the value is somewhat above normal. It's the mildest 'high' level, often an early warning.

The SCR (selective catalytic reduction) catalyst uses DEF to turn NOx into nitrogen and water. The ECM compares NOx before and after the catalyst to judge how well it's working. If it isn't, EPA rules require the engine to warn the driver and then derate.

What the lamp means

This code normally doesn't turn on a dash lamp. It's logged in the ECM for a technician to see, and often explains another active code.

How serious is it?

Green, yellow, red: three ways this can look

The same code can be a quick fix or a reason to shut down. Match your situation to the closest example.

Green

Keep an eye on it

A one-time code with no lamp, or the amber lamp clears after a few drive cycles and fresh DEF.

Yellow

Schedule a repair

Amber lamp with SCR efficiency or NOx codes that keep returning. Schedule diagnosis. These usually get worse, and inducement timers can be running in the background.

Red

Stop and get help

Blinking lamp, inducement countdown, or the engine is already derated to low power or 5 mph. Stop and get it diagnosed. Clearing codes alone won't reset a real inducement.

Common causes

The sensor reading itself is out of range or the condition is real, so look at the system:

  • Bad or diluted DEF, or not enough DEF being dosed
  • Crystallized or clogged DEF doser
  • Failing NOx sensor (very common)
  • SCR catalyst contaminated by oil or fuel, or worn out
  • Exhaust leak ahead of the sensors
  • Upstream engine problem raising NOx: EGR fault, boost leak

What you can check before calling

  • Check DEF level and quality first. It's the cheapest fix
  • Look for exhaust leaks or soot tracks at clamps ahead of the catalyst
  • Write down any countdown or derate message on the dash before it changes

Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers. For the bigger picture, read our guide: DEF warning lights and derate: what diesel drivers need to know.

Engines and sources

Listed by Cummins for: QSB 6.7, QSL 9, QSX 15, QSB 4.5, QSF 3.8 (With SCR), QSG 12. Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Cummins Tier 4 Fault Codes. Always confirm with Cummins service information (QuickServe) for your engine serial number.

Look up another code

Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).

Questions

What does Cummins fault code 3164 mean?

Cummins fault code 3164 is J1939 SPN 4360 FMI 15: Aftertreatment 1 SCR Intake Temperature - Data Valid But Above Normal Operating Range - Least Severe. In plain terms: scr intake temperature: reading above normal (least severe).

Can I keep driving with Cummins code 3164?

Usually, yes. This code doesn't normally turn on a lamp by itself, but check for other active codes that might be more serious. Look at the green, yellow and red examples on this page to judge your situation.

What is the SPN and FMI for Cummins code 3164?

SPN 4360 identifies the part or system (Aftertreatment 1 SCR Catalyst Intake Gas Temperature). FMI 15 describes the type of failure: reading above normal (least severe).

What usually causes Cummins code 3164?

The most common causes are: bad or diluted DEF, or not enough DEF being dosed; crystallized or clogged DEF doser; failing NOx sensor (very common).

Diesel down in the Midlands?

We work on Cummins-powered pickups, vans and medium-duty trucks across Lexington, Columbia and the Midlands, on site at your yard or roadside.

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