Description
Product Overview
The iFJF Downstream NOx Sensor SNS317A is engineered for 2017-2019 Chevrolet Silverado and GMC Sierra 2500HD/3500HD trucks equipped with the 6.6L L5P Duramax diesel engine. The L5P generation introduced a more sophisticated SCR system requiring precise NOx monitoring — when the downstream sensor fails, fuel economy drops, DEF consumption spikes, and the truck may enter reduced-power limp mode. This pre-calibrated sensor restores proper emissions system function without any dealer programming.
Key Features
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L5P-Specific Engineering: Designed for the 2017-2019 L5P Duramax platform with updated sensing technology that matches this generation's faster ECU communication and response requirements.
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Pre-Calibrated for Instant Operation: Factory-programmed with the correct calibration data — install, clear codes with a scan tool, and the sensor communicates with the ECU immediately with no VIN coding.
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Restores Fuel Economy: A failing NOx sensor causes the ECU to over-inject DEF fluid to compensate, wasting expensive DEF and reducing overall efficiency. Replacing the sensor returns DEF consumption to normal rates.
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Double-Sealed Connector: Weather-sealed 6-pin connector prevents moisture ingress that causes intermittent NOx sensor faults — especially critical in snow-belt states where road spray is constant.
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Heavy-Duty Stainless Probe: Engineered to withstand the L5P's elevated exhaust gas temperatures during sustained heavy towing and active DPF regeneration events.
Compatibility
| Make |
Model |
Engine |
Years |
| Chevrolet |
Silverado 2500HD / 3500HD |
6.6L L5P Duramax |
2017-2019 |
| GMC |
Sierra 2500HD / 3500HD |
6.6L L5P Duramax |
2017-2019 |
Note: For 2020+ L5P models, verify sensor part number compatibility as mid-cycle changes may apply. For off-road and competition use only.
Specifications
| Specification |
Details |
| Part Number |
SNS317A |
| Position |
Downstream (Post-SCR Catalyst) |
| Connector |
6-Pin Weather-Sealed |
| Engine Platform |
L5P Duramax 6.6L (Gen 5) |
| Application |
Off-Road / Competition Use Only |
Why Choose iFJF
The L5P Duramax is a premium engine option — don't let a failed NOx sensor keep it parked or limping. Our SNS317A delivers the same sensing precision as the OEM sensor at a significant cost savings. Pre-calibrated for true plug-and-play installation — no scan tool subscription, no dealer visit, no downtime. 90-day satisfaction guarantee.
Frequently Asked Questions
Q: What DTCs indicate a failed downstream NOx sensor on the L5P?
A: Common codes include P2200 (NOx Sensor Circuit Bank 1 Sensor 2), P2201 (Range/Performance), P229E (NOx Sensor Circuit Performance), and related P22A0-series codes. Always verify with a scan tool which sensor position is faulting before ordering.
Q: Is this sensor different from the LML (2011-2016) sensor?
A: Yes. The L5P (2017-2019) uses a different NOx sensor with an updated communication protocol compared to the LML. The LML sensor (5WK96645H) is physically and electrically different and not interchangeable. Verify your engine generation before ordering.
Q: Do I need to perform a forced DPF regeneration after replacing?
A: Not normally. Clear the DTCs after installation and the ECU will manage emissions system operation automatically. A forced regen is only needed if the truck was in a reduced-power state with significant soot accumulation.
Q: How does this compare to the dealer sensor?
A: The SNS317A uses the same wideband zirconia sensing technology and is manufactured to meet or exceed the OEM sensor's performance specifications. The primary difference is price — typically 50-60% less than dealer retail for the identical function.
Q: Can I install this myself?
A: Yes. Access the downstream sensor (post-SCR, near the tailpipe section), unplug the weather-sealed connector, unscrew the old sensor (22mm or 7/8-inch wrench), install the new sensor, reconnect, and clear codes. Approximately 20-30 minutes with basic hand tools.
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