Bosch EDC17CP20 ECU Guide: VW Transporter, Amarok, Crafter and Audi A4, A6 Files and Tools

A Transporter arrives on a trailer. Someone tried a remap over OBD, the laptop dropped its USB connection halfway through the write, and now the van cranks but won’t fire. The ECU comes out, goes on the bench, and the label shows a Bosch hardware number of 0281016272 with a VW part number starting 03L906022 underneath. That’s an EDC17CP20, and 0281016272 is the hardware number we see most often for this family: eight published files in our catalogue carry it. The first job here isn’t tuning. It’s getting the unit back to a known factory state, which means finding the original file that matches this exact ECU, not one that merely looks close.

This guide is built from the 476 EDC17CP20 files currently published in our catalogue. Most are Volkswagen Transporter reads, followed by the Amarok and the Audi A4 and A6, with a handful of Crafters. The part numbers, software versions, engine codes and counts quoted below come straight from those listings, so you can hold them up against what’s on your bench and see quickly whether a matching file exists.

Identifying an EDC17CP20 on the car and on the bench

On the vehicle, the quickest check doesn’t need a screwdriver. Connect VCDS or ODIS, open engine module 01 and read the identification. You’ll get the VAG part number, the four-digit software version and, on most cars, the engine code. With that pair of numbers (for example 03L906022CD 9118) you can already tell whether a matching original exists before anything gets unplugged.

On the bench, the Bosch label carries the rest. Expect to see these fields:

• ECU type: printed as EDC17CP20. Don’t mix it up with EDC17C46 or EDC17CP14, which also turn up on VAG diesels of a similar age and take different files.
• Bosch hardware number: ten digits starting 0281, often printed with spaces (0 281 016 272). This identifies the physical unit, not the software loaded into it.
• VAG part number: 03L906019 or 03L906022 plus a one- or two-letter suffix on nearly every Transporter, Amarok and Audi unit we list. The Crafter files in our catalogue are the odd ones out and carry 076906022P.
• Bosch software number: ten digits starting 1037. This is Bosch’s own identifier for the calibration and the most precise number you can match on.

The hardware numbers with the most EDC17CP20 files in our catalogue are:

• 0281016272: 8 files
• 0281017553: 5 files
• 0281016376: 3 files
• 0281018004: 2 files

Individual listings also show 0281016049, 0281016812, 0281016819 and 0281018002, so don’t assume an unfamiliar 0281 number means it isn’t a CP20. Many of our files don’t have the hardware number filled in at all, because the read was done over OBD and the tool only reported the software side.

The label tells you what the ECU was built as. It doesn’t always tell you what’s running in it now. A unit that has had a dealer update will report a newer software version and a different 1037 number from the ones printed on the sticker, so read the identification from the ECU itself before you trust the label. The reverse is also true: one hardware number carries many calibrations. In our catalogue 0281016272 appears with 03L906022 CC 7529 and with 03L906022CD 9118, among others.

Be careful with the four-digit version on its own. Version 9978 appears on Amarok files with part numbers 03L906019FA and 03L906019FF, and on an Audi A4 file with 03L906022NN. Versions 9977 and 9979 show up on both A4 and A6 part numbers. Those are different calibrations for different vehicles. Match the full part number plus version, and the 1037 number where you have it. If you’re unsure which figure is which on a sticker, our walk-through on reading ECU label numbers covers the Bosch layout field by field.

For reference, the software identifiers that come up most often in our EDC17CP20 listings are 03L906022CD 9118 (four files), then 03L906019FA 9978, 03L906022CC 8273 and 03L906022CH 9126 with three each. After those comes a long tail of numbers with two files or one, which is normal for a family that was updated as many times as this one.

Vehicles and engines in our EDC17CP20 catalogue

By brand, Volkswagen accounts for 407 of the EDC17CP20 files in our catalogue (some are filed under VW and some under Volkswagen, which is the same make) and Audi for 69. The model split is lopsided. The Transporter alone has more files than every other model put together, and that fits the work: vans cover big mileage, get remapped, get EGR and DPF trouble and have ECUs swapped more often than the cars that share the same controller.

Model	Brand	Files in our catalogue	Engine codes on example listings
Transporter	VW	281	CAAB
Amarok	VW	56	CDCA
A4	Audi	52	CAGA, CAGC
A6	Audi	17	CAGB
Crafter	VW	4	not given on the listings

Across the whole family, the engine codes with the most files in our catalogue are CAAC with 69 and CFCA with 68, followed by CCHA (43), CAAA (27), CDCA (26), CDBA (20), CAAE (19) and CCHB (18). CAGA, CAGB and CAHA have 17 files each, CAAB has 16, CAHB has 12, CAAD has 11 and CAGC has 6.

Treat the engine code as a cross-check rather than a way to pick a file. One engine code covers several part numbers and software versions. The A6 listings with CAGB, for example, include both 03L906019AT and 03L906019C part numbers, each with several software versions. Two vans with the same engine code and the same year can easily need different originals.

Crafter coverage is thin at four files, and the engine code isn’t recorded on those listings. With a Crafter on the bench, go by the label and the ECU identification, not by the model name. The same applies to any vehicle not in the table: EDC17CP20 was used more widely than our catalogue shows, and a missing model here only means we don’t have a file for it yet.

Example EDC17CP20 files from our catalogue

The table below is a cross-section of real listings: vans, pickups and saloons, several read tools, and both stock and modified files. Titles, numbers and links are copied from the product pages. Where a listing doesn’t state the hardware number or the read tool, the cell says so.

File	Vehicle	Hardware no.	Software no.	Read with	File type
VW TRANSPORTER EDC17CP20 0281016272 03L906022 CC 7529 1037510319 DUMP	VW Transporter	0281016272	03L906022 CC 7529 / 1037510319	not stated	Original
VW TRANSPORTER EDC17CP20 0281016272 1037518131 DUMP	VW Transporter	0281016272	1037518131	not stated	Original
VW TRANSPORTER EDC17CP20 03L906022CD 9118 DUMP	VW Transporter, CAAB	0281016272	03L906022CD 9118	KTAG	Original
VW TRANSPORTER EDC17CP20 0281016376 03L906022CC 5599 1037504737 DUMP	VW Transporter, CAAB	0281016376	03L906022CC 5599 / 1037504737	KTAG	Original
VW TRANSPORTER EDC17CP20 03L906022JD 9112 DUMP	VW Transporter	not listed	03L906022JD 9112	KESS V2	Original
VW TRANSPORTER EDC17CP20 03L906019AB 9125 DUMP	VW Transporter	not listed	03L906019AB 9125	KESS V2	Original
VW TRANSPORTER EDC17CP20 03L906022CD 9970 DUMP	VW Transporter	not listed	03L906022CD 9970	KESS V2	Original
VW AMAROK EDC17CP20 0281018004 03L906019FA 9978 1037558512 DUMP	VW Amarok, CDCA	0281018004	03L906019FA 9978 / 1037558512	Flex	Original
VW AMAROK EDC17CP20 03L906019FA 9978 1037558512 DPF EGR OFF STAGE1 TUNED	VW Amarok	not listed	03L906019FA 9978 / 1037558512	KESS V2	Chip tuning, DPF off, EGR off
VW AMAROK EDC17CP20 03L906019FA 8729 1037515253 DUMP	VW Amarok	not listed	03L906019FA 8729 / 1037515253	KTAG	Original
VW AMAROK EDC17CP20 03L906019FA 8729 1037515253 DPF EGR OFF DUMP	VW Amarok	not listed	03L906019FA 8729 / 1037515253	not stated	DPF off, EGR off
VW AMAROK EDC17CP20 0281016049 03L906022CS 6284 1037507693 DUMP	VW Amarok, CDCA	0281016049	03L906022CS 6284 / 1037507693	KTAG	Original
AUDI A4 EDC17CP20 03L906019AL 5488 1037504773 DUMP	Audi A4, CAGC	not listed	03L906019AL 5488 / 1037504773	KESS V2	Original
AUDI A4 EDC17CP20 03L906022NN 9978 1037560521 DUMP	Audi A4, CAGA	not listed	03L906022NN 9978 / 1037560521	KESS V2	Original
AUDI A6 EDC17CP20 03L906019AT 8434 1037518002 DUMP	Audi A6, CAGB	not listed	03L906019AT 8434 / 1037518002	KESS V2	Original
AUDI A6 EDC17CP20 03L906019C 9979 1037563149 DUMP	Audi A6, CAGB	not listed	03L906019C 9979 / 1037563149	KESS V2	Original
VW CRAFTER EDC17CP20 0281016819 076906022P 9022 DUMP	VW Crafter	0281016819	076906022P 9022	New Trasdata	Original
VW CRAFTER EDC17CP20 076906022P 7730 1037510917 DUMP	VW Crafter	not listed	076906022P 7730 / 1037510917	PCM Flash	Original

Two things stand out when you read the table as a technician rather than a shopper. First, modified files come in pairs with a stock file. The Amarok with 03L906019FA 8729 and 1037515253 has a plain dump and a DPF/EGR version, and the Amarok with 03L906019FA 9978 and 1037558512 has a plain dump and a stage 1 with DPF and EGR off. A modified file is built on one particular original. If your own read doesn’t match that original outside the areas that were changed, the modified file isn’t for your ECU, however well the sticker numbers agree.

Second, the same software version sits under different part numbers. 03L906019FA 9978 on an Amarok and 03L906022NN 9978 on an A4 share the last four digits and nothing else that matters. Filtering the shop by version number alone will throw up both, so always check the part number in front of it.

EDC17CP20 file types and when a workshop needs each one

For this family the catalogue is overwhelmingly stock files. Of the published EDC17CP20 products, 468 are in original files, 7 in chip tuning, 4 in EGR off and 3 in DPF off. Some modified files sit in more than one category, which is why those last three numbers overlap.

Original files

An original file is a read of an unmodified ECU with a known part number and software version. It’s the file you reach for most often, and not only for recovery. Typical reasons:

• A flash failed or was interrupted and the ECU no longer communicates or won’t start the engine.
• The van was tuned by someone else, the customer wants it back to stock, and nobody kept the original read.
• A tuner needs a clean base to work from and the car’s own read is already modified or suspect.
• A replacement ECU carries the wrong software for the vehicle and you want to put the correct calibration on it.
• You suspect a previous tune is behind a fault and want to compare the car’s read against a known stock file.

An original file won’t fix a sticking turbo actuator, a leaking injector, a split intercooler hose or a blocked DPF. If the fault was there before anyone touched the software, it’ll still be there after you load stock. Going back to original is still a good diagnostic step, though, because it takes the calibration out of the argument.

Chip tuning files

There are only seven EDC17CP20 tuning files in our catalogue, and at least one of them combines a stage 1 with DPF and EGR changes. A stage 1 on these engines is only as good as the hardware underneath. Before writing any tune, check boost against specified values, look at the MAF readings, and ask about the clutch and dual-mass flywheel on high-mileage vans. A tune on a van with a slipping clutch just turns an old problem into a warranty argument.

DPF and EGR solutions

These files change the software so the ECU stops monitoring or controlling the particulate filter, the EGR valve, or both. Be clear with customers about what that means. Removing or disabling a DPF or EGR system is not road-legal in the EU or the UK, or in many other countries, and a car that has had it done will fail an emissions test that looks for it. These files are for off-road, export and motorsport use. Also, the file doesn’t clean or repair anything. If the filter is blocked because of an injector or EGR fault upstream, that fault is still there.

Immo off and virgin files

We don’t list any immo off or virgin files for EDC17CP20 at the moment. On these VAG platforms the usual answer to a replacement ECU is either cloning, where you copy the complete contents (flash and EEPROM) of the original unit into an identical replacement, or a proper immobiliser adaptation with dealer-level tools such as ODIS or VCP. If you do need an immobiliser solution, it should only be for a vehicle the customer owns and can prove they own, and you’ll need to send a full read so it can be assessed.

Reading and writing EDC17CP20: OBD, bench and boot

The read tools recorded on our listings tell you how most workshops handle this ECU. KESS V2 is named on 401 of the EDC17CP20 files, PCM Flash on 48, Flex on 8, KTAG on 6 and New Trasdata on 5. In plain terms, the large majority were read over the diagnostic socket without removing the ECU, and a small number came off the bench.

OBD

For a healthy ECU with supported software, OBD is the easy route. KESS V2 and PCM Flash both cover EDC17CP20 on the VAG applications we see, and on most versions the tool handles checksum correction as part of the write. Two warnings. First, depending on the tool and the protocol version, an OBD read may save only the calibration area rather than a full image of the flash, and it won’t give you the EEPROM. Check what your tool actually saved before you rely on it as a backup. Second, later software versions on some EDC17 families carry tuning protection, and a write that the tool refuses over OBD usually has to be done on the bench or in boot mode instead. We explain how that protection works in our note on TPROT on EDC17 and MED17.

Bench

Bench mode means removing the ECU and talking to it through its connector with a harness, without opening the case. KTAG, Flex and New Trasdata all appear on our CP20 listings. On supported versions a bench read gets the flash and the EEPROM in one go, which is exactly what you want before you start any work that could go wrong. It’s also the sensible choice when the ECU is already off the car, or when OBD communication is unreliable because of other faults on the vehicle network.

Boot

Boot mode means opening the housing and forcing the processor into its boot loader with a boot pin or a probe on the board. On the units we see, the processor is from the Infineon TriCore family (TC1796 is what’s usually reported for this ECU, but read the marking on the chip before you pick a protocol). Boot is the last resort for an ECU that won’t respond to OBD or bench after a failed write, and the fallback when tuning protection blocks the other routes. Opening the case risks breaking the seal and the board if you’re careless, so do it on a clean, earthed bench. For a side-by-side of the three methods on this generation of Bosch units, see OBD, bench and boot mode on EDC17 and MED17.

Before you write anything

• Put a stabilised power supply on the vehicle for OBD work. A battery that drops during a long write is the classic way to brick one of these. A battery charger in boost mode is not a power supply.
• Save a full backup (flash and EEPROM) and label it with the VIN, the part number, the software version and the date. Keep it somewhere that isn’t the laptop you’re flashing from.
• Turn off sleep, updates and screen savers on the laptop, and use a USB cable you trust.
• If the file was edited outside the tool, make sure checksums are corrected before writing. A wrong checksum on a Bosch EDC17 usually means the ECU won’t start the engine or won’t communicate.
• Compare the file you’re about to write with the car’s own read. If the part number and 1037 number don’t line up, stop and find out why.

Common EDC17CP20 problems and bench notes

Interrupted or failed flash

This is the Transporter from the opening paragraph. The symptoms are usually one of two: no communication at all on module 01, or communication but no start with a fault pointing at the software. Resist the temptation to keep retrying over OBD, because each failed attempt can leave the flash in a worse state. Try the tool’s own recovery function first. If that doesn’t work, go to bench and, if needed, boot mode, and write a matching original. The matching part matters: the file needs the same part number and software version as the unit was running, or as close as you can get with the same hardware number. Our guide on recovering a bricked ECU after a failed flash goes through the order of steps.

Immobiliser after an ECU swap

A used EDC17CP20 from another vehicle will usually let the engine fire for a second or two and then cut it, because the immobiliser data in the ECU doesn’t match the car. There are two clean fixes. Clone the original ECU into the replacement, which needs the same hardware number and ideally the same part number, and a full read of both units. Or adapt the replacement to the car with ODIS or VCP, which on most of these vehicles needs an online login and the security access data. If the original unit is so damaged that its EEPROM can’t be read, the job gets harder and you’ll likely need specialist immobiliser work.

Limp mode after a tune

Low power with boost deviation faults, or an EGR or DPF warning soon after tuning, is common on high-mileage vans. Before blaming the map, check the basics: boost leaks and split hoses, MAF readings at idle and under load, the turbo actuator and vanes, and the DPF differential pressure readings. Then write the original file back and road-test. If the fault disappears on stock software, the tune is asking for more than the hardware can deliver. If it stays, you’ve found a mechanical fault that the tune merely exposed.

Wrong calibration on a replacement unit

We see this with ECUs bought second-hand. The hardware number matches, the van starts after adaptation, but it runs badly, sets odd faults or has the wrong power. The software inside is for a different engine code or a different gearbox. Read the part number and software version from the replacement and compare them with the old unit. If they differ, write the original file that matches the car, not the one that came with the ECU.

Listings with two 1037 numbers

A few EDC17CP20 titles in our catalogue carry two Bosch software numbers, for example a Transporter listing with 0281017553, 03L906019GG 3313, 1037515577 and 1037524687, and an Amarok listing with 0281018002, 03L906019FF 9744, 1037518110 and 1037526360. In most cases that reflects an ECU that has been updated at some point, so the read contains more than one identifier. Match both numbers against your own read if you can, and if only one matches, ask before you write it.

Questions workshops ask about EDC17CP20

Is the EDC17CP20 in a Transporter the same as the one in an Amarok or an Audi A4?

It’s the same ECU family, and the hardware can overlap, but the software is specific to each application. The part numbers in our catalogue show that clearly: the Transporter, Amarok and Audi files use different 03L906019 and 03L906022 suffixes. Never move a file from one vehicle to another because the ECU type matches.

Can I read an EDC17CP20 over OBD with KESS V2?

On most versions, yes, and 401 of the files in our catalogue were read that way. The limits are tuning-protected software and damaged ECUs, where you’ll need bench or boot. Check whether your tool saved a full flash or only the calibration before you treat the read as a backup.

Why don’t two files with software version 9978 match each other?

Because the version number is only part of the identifier. In our listings 9978 appears on Amarok part numbers 03L906019FA and 03L906019FF and on an Audi A4 with 03L906022NN. Match the whole part number, the version and ideally the 1037 number.

Do I need the EEPROM as well as the flash?

For anything involving an ECU swap, cloning or immobiliser work, yes. The flash holds the program and calibration; the EEPROM holds data that belongs to that specific car. For a straight remap over OBD on a healthy ECU the tool handles what it needs, but a full backup including the EEPROM costs you a few minutes and can save the job.

The customer’s ECU has a 1037 number that isn’t in your catalogue. Can I use the closest one?

Not as a first choice. A close file with the same part number but a different software version can start the engine and still carry the wrong adaptations or maps. Send us the numbers and a read of the ECU, and we can check whether a matching file exists or can be sourced.

Is a DPF off file for EDC17CP20 legal on the road?

No. Disabling a DPF or EGR system isn’t road-legal in the EU, the UK and many other countries. Those files are sold for off-road, export and motorsport use, and it’s the workshop’s responsibility to know where the vehicle is going.

After a failed write, which file should I load?

The original that matches the software the ECU was running when the write failed, identified by part number, version and 1037 number. If you have your own full backup from before the job, use that first. A catalogue file is the fallback when there’s no backup or the backup is incomplete.

When the EDC17CP20 file you need isn’t listed

With 476 published files and a long tail of software versions, there will be units we don’t have yet. If yours isn’t in the EDC17CP20 section of the shop, send what you have through the file request form: the Bosch hardware number (0281…), the VAG part number and four-digit software version, the 1037 software number, the vehicle and engine code, and the tool you read it with. A full read, flash and EEPROM, lets us compare it against what we hold and tell you quickly whether we can match it. Photos of the label help when numbers are worn or partly covered by a sticker from a previous repair.