Cummins fault code 5221
Engine Air Shutoff Status: erratic or intermittent signal
What it means
Cummins' description: Engine Air Shutoff Status - Data erratic, intermittent or incorrect.
SPN 3667 is Engine Air Shutoff Status. FMI 2 means the signal is jumping around, dropping in and out, or doesn't make sense compared to other readings.
Some Cummins engines have an electronic intake throttle to help regeneration and a smooth shutdown. Others have an air shutoff valve that can stop the engine in an emergency.
What the lamp means
A red stop lamp means Cummins treats this as serious. Stop the engine as soon as you can do it safely and get it checked before running it again.
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. Cummins rates this a red stop lamp code, so if the red lamp is on, go by the red example.
Keep an eye on it
An informational code reminding you a shutoff test is due.
Schedule a repair
Rough running, slow regens, or throttle codes that keep coming back. Have it cleaned or replaced.
Stop and get help
Engine shuts down or won't start because the air shutoff is closed or stuck. It needs a technician on site.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- Throttle plate sticking from soot and oil
- Air shutoff tripped and not reset
- Air shutoff maintenance test overdue
What you can check before calling
- Check whether the air shutoff has been tripped and needs resetting
- Look for oil and soot buildup at the intake throttle
Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.
Engines and sources
Listed by Cummins for: QSB 6.7, QSL 9. 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.
Same SPN, other failure types
Related Intake throttle and air shutoff codes
- 5292 SPN 520809 FMI 31
Excessive Time Since Last Engine Air Shutoff Maintenance Test: condition exists - 6493 SPN 3464 FMI 3
Electronic Throttle Control Actuator Driver Circuit- Voltage above normal, or shorted to high source: circuit voltage high / shorted high - 6494 SPN 3464 FMI 4
Electronic Throttle Control Actuator Driver Circuit- Voltage above normal, or shorted to low source: circuit voltage low / shorted low - 6496 SPN 3464 FMI 5
Electronic Throttle Control Actuator Driver Circuit- Current Below Normal or Open Circuit: circuit open / current low - 6497 SPN 51 FMI 3
Engine Intake Throttle Actuator Position Sensor Circuit- Voltage above normal, or shorted to high source: circuit voltage high / shorted high - 6498 SPN 51 FMI 4
Engine Intake Throttle Actuator Position Sensor Circuit- Voltage above normal, or shorted to low source: circuit voltage low / shorted low
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 5221 mean?
Cummins fault code 5221 is J1939 SPN 3667 FMI 2: Engine Air Shutoff Status - Data erratic, intermittent or incorrect. In plain terms: engine air shutoff status: erratic or intermittent signal.
Can I keep driving with Cummins code 5221?
No. Cummins assigns this code a red stop lamp. Stop the engine as soon as it's safe and have it checked before running it again. Look at the green, yellow and red examples on this page to judge your situation.
What is the SPN and FMI for Cummins code 5221?
SPN 3667 identifies the part or system (Engine Air Shutoff Status). FMI 2 describes the type of failure: erratic or intermittent signal.
What usually causes Cummins code 5221?
The most common causes are: throttle plate sticking from soot and oil; air shutoff tripped and not reset; air shutoff maintenance test overdue.
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.