Siemens and Continental ECU Numbers: 5WS40, 5WK4/5WK9, 5WP4, A2C and S1101 Explained

A Range Rover Sport arrives with a diesel ECU whose label says 5WS40278B-T and, underneath, NNS505510. The customer’s mate has already told him it’s a Siemens box and that Siemens numbers are all the same. They aren’t. Siemens VDO, and Continental after 2007, used several separate numbering families, and each one tells you something different about what’s in the box and which file it can take.

5WS40: the SID diesel family

5WS40 followed by three digits and a letter is the Siemens reference on the SID range of common-rail diesel controllers: SID201, SID204, SID206, SID803, SID803A, SID807 and so on. The suffix letter moves with the software revision, and a trailing -T or similar marks a variant on some. From the catalogue:

• 5WS40278B-T with NNS505510, SID204, Range Rover Sport 2.7 TDV6
• 5WS40405E with NNV506650, SID204, Range Rover
• 5WS40535H-T with XP240M2000000, SID204, Jaguar XF

The number after it (NNS, NNV, NNW on Land Rover, XP on Jaguar, 96xxxxxx80 on PSA, xxxx-12A650-xx on Ford) is the car maker’s number. A 5WS40 alone will usually identify the ECU type but not the exact calibration; the OEM number narrows it, and on Ford the 14C204 strategy number narrows it further.

Later SID boxes stop printing 5WS40 and use the newer Continental format instead. A SID310 on a Dacia Duster reads 237107137R 237619923R; a Renault Kadjar SID310 adds 10361622AA; a Mercedes CLA180 W117 with the same SID310 shows A6079002300 6079031903 10371711AA. That 10xxxxxxAA number is Continental’s own software identifier and is the closest thing to the Bosch 10SW number on these boxes.

5WK4 and 5WK9: body and immobiliser modules

Siemens numbers starting 5WK are body electronics, not engine controllers. On BMW CAS3 modules you’ll find them next to the BMW 6135 number, for instance 6135 9147222-01 with 5WK4 9514XBR on a 520d E60, or 6135 9287534-01 with 5WK4 9516PBR on an X1 E84. Other CAS3 labels in the catalogue only show the BMW number (6135 6943835-01 on a 335i E90, 6135 9389116-01 on an X5 E70). For a CAS dump the BMW number plus the hardware index (-01, -02) is what matters; the 5WK part is secondary. 5WK9 turns up on clusters, keyless modules and older immo boxes; check the label, because the same prefix covers very different parts.

5WP4: Simos

Simos engine ECUs (VAG small petrol engines, and later the PCR2.1 diesel) carry a 5WP4 number beside the VAG number. A VW Polo Simos 3PE reads 03E906033 with 5WP40163 03; the same hardware sits in a Seat Cordoba as 03E906033 D and a Skoda Fabia as 03E906033 A. The VAG suffix letter decides the file, the 5WP4 number confirms the board.

A2C: the Continental era

After Continental took over Siemens VDO, new hardware got A2C numbers. They show up on engine ECUs, gearbox modules and GM boxes with Continental hardware. An Opel Insignia Delco E98 in the catalogue lists A2C113908010 with GM number 55511940; a Chevrolet Colorado E98 shows A2C928169001 with 55596113 and 12685771; another Insignia has A2C928169000 with 55507349. The A2C number is the hardware; the GM 555xxxxx number is what identifies the calibration.

S1101 and S1801: EMS and SID software labels

Renault-fitted Siemens boxes print an S-number that is the software build. EMS3132 on a Renault Megane reads S110140000 A alongside 8200298162 and 8200298290. On a Mercedes SID307 you’ll see S180170004A with 6079010100 6079021200 6079034200, and on a Renault Megane SID307, S180153104 A with 237102426R 237101908R. Treat the S-number like a Bosch 1037 number: quote it if it’s printed.

Pairing them with OEM numbers when ordering

1. Write down every number on the label, in the order printed.
2. Identify the ECU type from the Siemens or Continental reference (5WS40 = SID, 5WP4 = Simos, 5WK = body module, A2C = later Continental hardware).
3. Search the OEM number first (8200…, 237…, 96…80, NNx, 6135, 555…). Our product titles carry the OEM number because that’s what most tuning tool databases key on.
4. If the OEM number returns several files, use the software reference (10xxxxxxAA, S1xxxxxxx, the 5WS40 suffix letter) to pick the right one.

Two warnings. Siemens SID boxes on PSA and Ford are often locked for OBD reading and need a bench or boot read (BitBox, Flex, KTAG on the older ones); the label numbers don’t change that. And on Renault, a Siemens ECU with a dead UCH is not fixed by a file swap; the UCH needs pairing with CLIP first.

Search the OEM number in our original files, or start from the SID204 and CAS3 model pages. For a label that isn’t listed, send us the photo through the file request form and we’ll match it by hand.