Erklärung zum Lesen von Bosch-Teilenummern auf VAG-Motorsteuergeräten

A Bosch engine control unit fitted to a VAG vehicle carries two separate numbering systems at the same time: the Bosch internal reference stamped on the unit itself, and the VAG OEM reference printed on the label. Both matter, and they do not always agree with what an online catalogue returns for your registration. Understanding how both systems are structured — and where they diverge — is the single most reliable way to confirm that a used ECU will actually work in your car before you pay for it.

Two Numbers, One Unit: The VAG OEM Reference and the Bosch Reference

Every Bosch ECU fitted to an Audi, VW, Seat or Skoda carries a VAG part number in the format XXX YYY ZZZ A, where the first three digits identify the vehicle series, the middle three identify the component group, the last three identify the specific part, and the trailing letter is the index. Alongside this, the unit itself is stamped with a Bosch reference in the format 0 261 XXX XXX (Motronic) or 0 281 XXX XXX (EDC diesel). The Bosch reference is the more stable identifier across platforms — the same Bosch hardware revision sometimes appears under different VAG numbers because different vehicle programmes received it at different times.

The critical point is that neither number alone is sufficient. The VAG number tells you which car the part was originally ordered for. The Bosch number tells you which hardware and software generation the unit contains. A mismatch between what the car expects and what the unit contains will either result in no communication at all, or a unit that communicates but refuses to start because the immobiliser byte or the injection variant coding does not match.

Decoding the Bosch Reference

The Bosch part number for an engine management unit always begins with 0 261 (petrol, Motronic family) or 0 281 (diesel, EDC/EDC15/EDC16/EDC17 family). The digits that follow identify the hardware variant, and the final two or three digits in the full reference identify the software calibration level. This is the segment that is most often overlooked and most often wrong on a pulled unit. For comparison, see Audi A6 C5 Allroad Air Suspension ECU Faults Diagnosis Guide.

0 261 206 XXX — ME7.x Motronic, used widely on 1.8T and 2.7T V6 petrol engines, A4 B5/B6, A6 C5, Passat B5
0 261 207 XXX — ME7.1.1 variant, found on later 1.8T applications including Golf 4 and Octavia 1Z petrol
0 281 010 XXX — EDC15P, 1.9 TDI PD 100–150 hp, Passat B5, A4 B5/B6, Golf 4 TDI
0 281 011 XXX — EDC15VM+, used on 2.5 TDI V6 applications, A6 C5, A8 D2
0 281 012 XXX — EDC16U, early 2.0 TDI 140 hp, Golf 5, A3 8P, Passat B6
0 281 013 XXX — EDC16U34/CP34 variant, later 2.0 TDI and 1.9 TDI PD, A4 B7, Octavia 1Z

Within each of these families the last segment varies by fuel calibration, injector type (for PD versus common-rail engines), torque map, and emissions standard. Swapping between the last-digit variants is not always possible even with recoding — some require a software flash that dealer-level ODIS equipment must apply.

Why the VAG Index Letter Matters More Than the Base Number

The trailing letter on a VAG part number — the A, B, C or D at the end — denotes a hardware or calibration revision. In general, a higher index is a later revision and is not a simple drop-in for a lower one. For example:

038 906 019 HJ und 038 906 019 KP both describe 1.9 TDI 130 hp PD ECUs on A4 B6, but the suffix letters indicate different injector correction maps and different immobiliser variant tables. Fitting KP where HJ was expected produces a crank-no-start because the SKC table does not align.
8E0 907 115 E und 8E0 907 115 M cover different Bosch ME7.1.1 builds for the 1.8T 150 hp on the A4 B6. The E revision was phased out mid-production; the M carries a revised knock sensor threshold. Both are mechanically compatible but coding differs.

When buying a used ECU, always confirm the full VAG number including every suffix letter. Sellers who list only the base number — the first nine digits without the trailing characters — are giving you incomplete information, and the responsibility for compatibility falls entirely on the buyer.

Affected Vehicles and Production Ranges

Bosch Motronic and EDC units under VAG application cover an exceptionally wide production window:

Audi A4 B5 (1994–2001): ME5.9, ME7.1, EDC15V, EDC15P
Audi A4 B6 (2001–2005): ME7.1.1, EDC15P+, EDC15VM+
Audi A4 B7 (2005–2008): MED9.1, EDC16U34
Audi A6 C5 (1997–2005): ME7.1, ME7.1.1, EDC15VM+, EDC16
Audi A6 C6 (2004–2011): MED9.1, EDC16CP34, Siemens PPD
VW Passat B5/B5.5 (1996–2005): ME5.9, ME7.1, EDC15P/V
VW Passat B6 (2005–2010): MED9.1, EDC16U
VW Golf 4 (1997–2004): ME7.1, EDC15P
VW Golf 5 (2003–2008): MED9.1, EDC16U, EDC17
Skoda Octavia 1U (1996–2010): shares B5 platform ECUs
Skoda Octavia 1Z (2004–2012): shares Golf 5 platform ECUs
Seat Leon 1M (1999–2006): ME7.1, EDC15P
Seat Leon 1P (2005–2012): MED9.1, EDC16U

Platform sharing is real and it is useful, but it comes with a caveat: the same Bosch hardware often had different VAG calibrations applied at the end of the assembly line to account for torque limits negotiated by marketing, emissions certification by region, and equipment-level restrictions (DSG versus manual, for example). A Golf 5 2.0 TDI 140 EDC16 unit does not automatically work in an A3 8P 2.0 TDI 140 without at minimum recoding the variant and confirming the injector type.

OEM Part Numbers to Cross-Reference

The following are plausible and well-documented references across the main Bosch Motronic and EDC applications on VAG vehicles. Use these as a starting point, then verify the full suffix against the donor vehicle’s sticker: A related diagnostic guide is Welche VW Golf 5 Module werden mit dem Audi A3 8P und Seat Leon 1P gemeinsam genutzt.

8D0 907 558 F — ME7.1, 1.8T 150 hp, A4 B5, Passat B5 (Bosch 0 261 206 644)
8E0 907 115 M — ME7.1.1, 1.8T 150 hp, A4 B6 (Bosch 0 261 207 680)
038 906 019 KP — EDC15P+, 1.9 TDI 130 hp, A4 B6, Passat B5.5 (Bosch 0 281 010 697)
038 906 016 CK — EDC15P, 1.9 TDI 100 hp, Golf 4, Octavia 1U (Bosch 0 281 010 040)
4F0 910 401 E — EDC16CP34, 2.0 TDI 140 hp, A6 C6, A4 B7 (Bosch 0 281 013 336)
03G 906 021 KA — EDC16U34, 2.0 TDI 140 hp, Golf 5, Passat B6, A3 8P (Bosch 0 281 012 557)

Exact number matching matters because these units carry immobiliser data, injection variant maps, and torque limitation tables that are not interchangeable between suffixes. A unit with a different trailing letter from the one listed in ETKA or ELSAWIN may fit physically and communicate over the K-line but will not start the engine or will trigger continuous fault codes on the instrument cluster.

Common Mistakes When Ordering a Replacement ECU

Ordering by engine code alone without checking the full part number — the same engine code (e.g. AWX) was fitted across several model years with different ECU revisions.
Accepting a unit described as “same as yours” by a seller who has only matched the first nine digits of the VAG number.
Assuming the Bosch reference printed on the unit overrides the VAG label — both matter, and the VAG label is the calibration-level identifier.
Ignoring the difference between a PD (pump-duse) ECU and a common-rail EDC — both may carry a 038 906 prefix but they are never interchangeable.
Forgetting that the immobiliser SKC code must be adapted after fitting any used ECU, regardless of how well the part numbers match.

Error Codes Associated With Wrong-Variant ECU Fitting

When an ECU variant mismatch exists, the vehicle typically logs the following through VCDS or ODIS:

P0606 — ECM/PCM processor fault; often appears when the software build is incompatible with the instrument cluster CAN message format
P0605 — ROM error in ECU; appears when the base calibration checksum does not validate
16395 / P0011 — Camshaft position timing over-advanced bank 1; appears when injection timing tables reference a different engine build than what is fitted
01176 (VCDS long code) — Engine control module: variant coding not recognised; logged when the byte written at adaptation does not match the ECU’s accepted range
00258 / P1616 — Glow plug relay circuit fault on diesel units installed in a vehicle expecting a different EDC variant, because the relay control output pin assignment changed between EDC15 and EDC16

These codes do not always confirm a hardware fault. Before condemning a unit, verify that the part number — all digits including suffixes — matches the original. An incorrect ECU that communicates but throws these codes is almost always a wrong-variant purchase, not a failed unit.

Häufig gestellte Fragen

Can I fit an EDC16 unit in a car that originally had an EDC15?

No. EDC15 and EDC16 are different hardware generations with different connector pinouts, different CAN configurations, and different immobiliser protocols. They are not mechanically or electronically interchangeable. Even if the connector could be adapted, the software architecture is incompatible and the vehicle would not start.

Does the Bosch number on the unit always match the VAG label?

Not always. VAG sourced certain hardware revisions from Bosch and then applied their own calibration flash before labelling the unit. The Bosch number identifies the hardware platform; the VAG label identifies the specific calibration. For ordering purposes the VAG label is the reference to use, not the Bosch stamp alone. For additional context, read Audi A8 D2 CAN-Gateway-Modul Originalteilenummern und Kompatibilität.

Which part of the VAG number is safe to ignore when cross-referencing?

None of it should be ignored, but in practice the first three digits (which identify the vehicle line) are the least restrictive — the same calibrated unit often appears under multiple vehicle-line prefixes on the same platform. The final suffix letters are the most restrictive and the most often mismatched in used-parts listings.

Do all VAG Bosch ECUs need immobiliser adaptation after fitting?

Yes. Every Bosch Motronic or EDC unit fitted to a VAG vehicle with an immobiliser (which covers all production from approximately 1996 onward) stores an SKC code that must be adapted to the new vehicle using VCDS, ODIS or a compatible tool. Without this step the engine will crank but not start, regardless of how well the part numbers match.

Where is the best place to read the full part number on the ECU itself?

On most VAG Bosch units a white label on the top or side of the ECU housing carries the VAG number in the XX X XXX XXX X format, and a second label or laser-etched stamp on the case carries the Bosch number. On heavily corroded or water-damaged units the label may be unreadable — in that case the Bosch number is usually etched directly into the aluminium cover and can be found after cleaning with a contact cleaner and a soft brush.

GiantParts supplies tested OEM Bosch engine control units for VAG applications with verified full part numbers, confirming suffix letters and Bosch hardware revisions before dispatch. European sourcing, worldwide shipping.

Geprüfte OEM-Elektronikteile und -Module finden Sie unter:
https://giantparts.eu/

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