What this sensor is and where it lives
This is a NOx sensor, not a temp sensor, even though they live in the same neighborhood on the exhaust system - so don't grab this thinking it'll fix a temp-related derate. It reads nitrogen oxide levels either upstream or downstream of the SCR catalyst depending on which position it's mounted, and the ECM uses that reading to manage DEF dosing and confirm the aftertreatment system is doing its job.
You'll see this number on Freightliner Cascadias and Western Star trucks running Detroit DD13/DD15/DD16 engines, mostly in the model years where Detroit standardized their NOx sensor part numbering across the lineup. The connector, harness length, and threaded boss all have to match your truck's specific mounting location - upstream and downstream sensors are NOT interchangeable with each other even if they look identical from across the shop.
Bottom line: pull the old sensor or check your VIN before you order. The part number stamped on the sensor body or the tag on the harness is your surest guide - don't just go by 'it's a NOx sensor and my truck's a Freightliner.'
How the cross numbers line up
A0101538128ASAS, EA0101538128, and RA0101538128 all trace back to the same Detroit Diesel design - the letter prefixes usually just indicate remanufactured vs. new vs. a specific packaging run, not a functional difference. Continental actually builds a lot of these sensors under contract, which is why you'll see 5WK97403 crossing over as the same physical part with a different label on the box.
Alliance and Torque Parts numbers (G01 A0101538128, TRDA1538128) are aftermarket houses packaging the same core design to fit the same mounting and connector spec. The sensing element and connector pinout need to match exactly - these aren't sensors where 'close enough' works, because the ECM is reading a specific signal protocol and any mismatch throws codes or reads garbage.
Watch the connector style closely if you're buying blind off a cross-reference sheet - Detroit revised connector hardware at points in the production run, and while the base part number carries over, some model years got a running change. If your old sensor's connector doesn't match what shows up on your doorstep, that's a sign to double check the number before you install it.
Ordering from PartStop
We keep this one in stock in Tacoma and ship it same-day if you're local or need it fast anywhere in the country. At $154.99 it's a straightforward swap for anybody dealing with NOx correlation faults or derates tied to aftertreatment performance.
Comes with our standard 6+ month warranty - if it's DOA or doesn't match your application once you get eyes on it, we'll sort you out. Just confirm against your VIN or the old sensor's number before it ships out; sensor swaps are cheap insurance against a comeback if you get the position wrong.
A0101538128ASAS Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to A0101538128ASAS. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| Continental | 5WK97403 |
| Detroit Diesel | EA0101538128, RA0101538128 |
| Torque Parts | TRDA1538128 |
| Alliance | G01 A0101538128 |
Frequently asked questions
Does A0101538128ASAS fit my 2018 Cascadia with a DD15?
Probably, but confirm by VIN or check the number on your old sensor first - Detroit ran multiple NOx sensor positions and connector variations across those model years, and this cross covers the common one, not necessarily every DD15 configuration out there.
Is this the same as the Continental 5WK97403?
Functionally yes, Continental builds this sensor design under contract for Detroit, so 5WK97403 crosses to the same physical part. Different label, same sensor - but double-check your old part's number against what you're ordering to be safe.
How do I know if I need the upstream or downstream sensor?
Check your fault code description and the sensor's physical location relative to the SCR catalyst - upstream reads engine-out NOx, downstream confirms SCR conversion. The part numbers aren't interchangeable between positions even though the sensors can look similar, so match the number off your old unit rather than guessing by symptom.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
Need the part, not just the reading?
Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.