Quick Answer: Flip most factory coolant temperature sensors over and you’ll find a stamped code — for a good chunk of the modern Audi lineup, that’s 059919501A. Match that exact string in any parts catalog and the logo on the box becomes irrelevant.
Why the OE Number Beats the Box
Every counter guy knows the scene: customer holding a crusty old sender in one hand, phone in the other, asking if “the green one” will fit. Buying by model year alone is a gamble. Manufacturers reuse sender designs across engines and generations, and a unit that threads happily into one 3.0 TDI can feed completely wrong resistance data to another car’s ECU. Wrong readings mean poor cold-start fueling, erratic fans, and a check-engine light that keeps coming back no matter how many sensors you throw at it.
The OE number ends that argument. It identifies the engineering drawing, not the marketing.
Cracking the Code: What 059919501A Actually Says
VW-Audi part numbers follow a logic that’s easy once somebody shows you the seams.
The group prefix
The leading 059 points to the 3.0-litre V6 TDI engine family — that’s where this sender lives. The middle block, 919 501, sits in the temperature-sender range of the catalog. So even without a lookup tool, the number tells you what the part is and roughly where it bolts on.
The revision letter
The trailing A is where most buyers stumble. Letters mark design revisions, and a later letter supersedes everything before it. If your old sensor reads 919501 with no letter and catalogs list 919501A, it’s the same part — A simply replaced the original run. One caveat: revisions occasionally carry updated resistance curves, so don’t assume every letter swap is cosmetic.
You’ll also see listings written as L059919501A. That leading L is supplier packaging coding, not a different sensor. Same drawing, same job.
Cross-Referencing Without Guesswork
Before ordering, run this five-point check:
| Check | What Confirms a Match |
|---|---|
| Stamped number | 059919501A legible on the sensor body |
| Revision letter | “A” supersedes the bare 919501 |
| Connector | Pin count and housing color match your old unit |
| Fitment | Confirmed against your VIN, not just the model name |
| Source | Seller lists OE number, not just “fits Audi” |
Run all five and you can buy confidently across brands — the identical sender circulates under Bosch, Febi, and others, often at half the dealer price. OSRAM’s version, the OS-WTA003 | OSRAM Coolant Temperature Sensor | Fits Audi | OE# L059919501A, is built to that same OE drawing and currently maps to two Audi applications, which is exactly why the VIN check matters before checkout.
Bottom Line
The stamped OE number is the only opinion that counts when temperatures sensors look alike but behave differently. If your scan tool flags a coolant sender fault on a 3.0 TDI, the OS-WTA003 | OSRAM Coolant Temperature Sensor | Fits Audi | OE# L059919501A is the no-drama fix — right number, right curve, none of the guesswork.
Recommended Part: OS-WTA003 – Direct-fit OE-grade replacement, ships same day.
