EDC16U1, EDC16U31 and EDC16U34 immo off and original files for VAG PD TDI (Golf V, A3, T5)

A Golf V 2.0 TDI on the ramp, label reads 03G906016BA, and the customer wants the immobiliser gone because the cluster is dead and a second-hand ECU is going in. Or a T5 with 070906016AJ on the box that cranks fine, fuels nothing, and the scan tool says the engine control module is blocked. Both are Bosch EDC16U1, and both are jobs where the file is easy and the identification is where people slip.

Three units, one family

Bosch built three EDC16U variants for the VAG pumpe-duse diesels and they don’t swap freely.

• EDC16U1: the first one, 2003 to about 2006. 2.0 TDI 16v BKD in Golf V, A3 8P and Touran (03G906016 numbers), 1.9 TDI BKC and BJB, plus the T5 2.5 R5 (070906016) and the T5 1.9 (038906016A).
• EDC16U31: replaced U1 on the later 1.9 (BXE, BLS) and the 2.0 8v BMM/BMP in Jetta, Passat B6 and A6 C6, with 038906016 and 03G906016 numbers. Chrysler and Jeep used it on the VM 2.0 diesel too (05187596AB in the Patriot).
• EDC16U34: the 03G906021 series, mostly 2.0 TDI 16v BKD/AZV/BKP with later software and the DPF-equipped 2.0 8v BMM in Golf V, Touran and Passat B6.

The hardware is close enough that a full read from one looks like the other, but the maps, the DPF strategy and the EEPROM layout differ. Order by the exact number on the label, not by engine code.

Reference files from the shop

• AUDI A3 EDC16U1 0281011847 03G906016BA 7000 1037371953 (original, and a STAGE1 EGR OFF version)
• VW TRANSPORTER EDC16U1 0281011568 070906016AJ 7002 1037372363 IMMO OFF
• VW CADDY EDC16U1 0281011882 03G906016DM 6045 1037371251 HOT START OK
• VW JETTA EDC16U31 0281012553 038906016AG 7000 1037374757 (original, EGR OFF STAGE1, and a VMAX OK version)
• AUDI A6 EDC16U31 0281012557 1037393547 03G906016HS 9908 STAGE1
• VW GOLF EDC16U34 0281013228 03G906021KK 9183 1037381019 IMMO OFF
• VW PASSAT EDC16U34 0281012719 03G906021MS 9390 1037382426 STAGE1
• VW TOURAN EDC16U34 0281013617 03G906021HN 9968 1037394984 original

OBD or BDM?

For a stage 1 or an EGR delete you only need the flash. EDC16U reads over OBD with KESS V2, MPPS and Galletto 1260 (slow, but it works) without drama. Write it back the same way, confirm the tool corrected the checksum, and you’re done. Hot-start fixes on the Caddy 03G906016DM are the same story, a flash-only job.

Immo off is different. On EDC16U the immobiliser data lives in the EEPROM (a 95xxx serial part on the board, size varies by version), so you need a full read. That means BDM: KTAG, BDM100 or a Flex on the bench, with the ECU opened and the frame on the pads. Some OBD tools claim EEPROM access on U1; treat it as a bonus, not a plan. Read flash and EEPROM, keep both, send us the EEPROM for immo off and write only that part back.

Where it goes wrong on the bench

Three things come back to us regularly.

1. Wrong pinout plate. The U1 and U31/U34 boards look alike, but the BDM pad row is not in the same place on every revision. Check the pad layout before pressing down, or you short the probe and get a blank read.
2. Immo off written into the flash instead of the EEPROM. The car still won’t start, and now the flash checksum is wrong as well.
3. Mixing a U1 file into a U34. Same engine code, different box, cranks and nothing. Compare the 1037xxxxxx software ID before you write anything.

Legal and practical limits

An EGR-off file on a 2.0 PD is a common request because the valve clogs and the swirl flaps go with it. In most EU countries it fails inspection if the fault is visible or the emissions test picks it up, and on DPF cars (the U34 with BMM) EGR off without matching the regeneration logic makes things worse, not better. Immo off is fine for a workshop replacing a dead ECU or cluster on a customer’s own car; it isn’t a substitute for key adaptation with VCDS or VCP when the original cluster is still alive. The immo off guide covers when each makes sense.

If you have the label and a read, send the full dump through the request page and tell us which version you need. Browse the EDC16U1 and EDC16U34 pages for stock versions by number, and the immo off category if the ECU is going into another car.