ECU module testing & repair

Page updated 30-12-23


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Our ECU inspection/repair service offers you the opportunity to have your suspect ECUs inspected & tested by an experienced ECU repair technician for minimal cost.  Upon testing, should your ECU fail, you will be contacted to discuss and confirm if you would like us to proceed with a rebuild.  No remedial work will be carried out without your authorization.

Inspection & testing charge for any petrol/diesel engine management ECU is £50 Minor/major repairs will only be enacted after testing, subject to authorization and payment.  PLEASE NOTE that the £50 is an inspection-test fee only, if the control unit is un-repairable, the charge still applies.  

Typical control module rebuild charges are in the range of £114-126 including parts & labour* on top of the test fee.  Rebuild means repairing the ECU plus replacing all parts that are known to be faulty and causing problems, plus re-engineering with up-rated components where necessary.

Typical minor repair, soldering and protection diode replacements. £18-£36 including parts & labour on top of the test fee. 

We stock, off the shelf.  Most common chips, semi-conductors, actuators & printed circuit boards.  Most other available parts can be sourced within 24hrs.

Second-hand ECUs from our stock range from £110-£700.

ECU turn-a-round here is normally 1-2* working days. Please allow for delivery at about 1 working day (each way).

Testing fees for auto gearbox control modules £105  ABS modules £50  Airbag control module testing including accident memory clearing £50  Range Rover BeCM units £80  BSi units £50  EDC-15-M-V-C2 modules £50  Mercedes combined MAF-ECM £65  Diesel engine management ECU £50

Please email for EU and overseas postage costs, method of payment, we except the Äuro  (no Western Union please) plus details of turn-a-round times (EU postage costs are not prohibitive).

We have just taken delivery of an Integra ECM interrogator.  Which will increase the range of ECM's we can test in our workshop.  The Integra set up, will test most Bosch & Siemens body control modules, as well as many OE equipment VAG, Merc & BMW control units.  Inspection & testing charge for Body Control Modules is £50.

We also test and repair some LPG kit control modules!  Please ring with your application.  So we confirm if we have the test program in house!

Freerunning ECU rebuilds (at extra cost) free running ECUís are specially built with no immobilizer code function programmed in to the EPROM. These units are very useful when a problem arises with the vehicles coded key immobilizer function,  it can be very expensive to replace the whole coded key system usually around £450.00 but can be up to £1200.00,  we can supply a free running ECU modules, depending on application.  A free running ECU is also useful if you are not sure your problem is coming from the ECU or the coded key immobilizer, ESN, code grabbing multiplexer or host wiring.  Free running ECUís cure both problems as they run independently of the vehicles immobilizer. These units will not need to be reprogrammed by the main dealer in the future should you loose the command key, saving further costs.  Some older modules will require extensive parts replacement to achieve freerunning status, thus adding substantial cost.  Later modules, about 2004 onwards tend to be a very simple conversion.  It must be noted, removing the immobilizer function, may invalidate your insurance should the vehicle be stolen in the future.

Re-programmed freerunning ECUís

Re-coding, programming, mapping & EEPROM erasure, ROM ultra violet erasure & KAL live flashing costs vary between makes and exact requirements, please email for a quote.

ENCLOSED with the ECU should be:
Details of vehicle make, year & model
A list of vehicle fault symptoms and diagnostic work
Return address, phone number and current email address (as we are moving towards paperless system of reporting & billing).

When posting an ECU for testing please fill in & print off this form and include it with your ECU.

Without exception no testing will be enacted for non-account customers without pre-payment. 

  Card payments can be made over the phone by ringing 01553 782929.  Monday to Saturday 8.30am - 5.30pm.

Our preferred payment method is via BACS using your invoice number as a reference for payment - please email us for our bank details!

ECUs travel well inside a Jiffy padded bag.  Royal Mail Special Delivery is recommended within the UK.  Avoid DHL, they sub-contract final delivery out, to keep costs down, which has proved to be less reliable than Royal Mail.

Postal address:  Auto-Tec Diagnostics, Unit 7 Austin Fields Industrial Estate, King's Lynn, Norfolk, PE30 1PH.

We will test and repair selected motorbike modules, please contact us by email

Turn-a-round times for testing & repairs is about 24-48hrs.

(*Specialist manufacturers mostly, Italian & TVR. Some parts may take ten days to arrive and cost a fortune).

Pictures of ECU repairs in progress

Why have this service? and just source a secondhand or exchange module.  Since around 1992 motor vehicles have increasingly had the ECU code locked to the ignition key making rebuild not exchange the way forward to getting a vehicle back on the road. 

With the introduction of Catalytic Converters, the fuel injection system came of age. It simply was not possible to get the carburetor to provide the degree of fuel metering control required by the new engine management systems & thus emissions. Every new car since 1993 (K Reg) has come equipped with fuel injection of one kind or another, controlled by a computer.  We specialize in customer 'own unit' rebuild and re-engineering of automotive engine control units. This means you get your own ECU back.

When exchanging, you have NO IDEA what you are getting back.  Worse still, the ECU you get back could have unusual intermittent faults that no one has been able to detect or repair.  Saving Main Dealer re-programming costs and inconvenience are avoided if your own ECU is re-fitted. It is also becoming more common that other types of exchange ECU are not working because of vehicle coding problems (the ECU is coded to work only with your vehicle)  this possibility is avoided if your own ECU is re-fitted.  Any ECU with a code-grabbing function is going to need keys, ECN and main ECU all set at the same time.  

Performance & Up-rating.  Performance up-rating using Dastek Unichip piggy-back technology.  Emerald ECU M3DK re-mapping software.  TDI Superchip kits.  Up-rating/remapping available. Please email for more details/prices.

Electronic Ignition Modules.  We are equipped to test & repair by return of post (test fee £14.50 to include return postage) Any ignition modules from older cars.  Second hand modules available for some applications.  I've collected some odd ones over the years, for info & availabilty please email

Our testing bench.


Test Fees

Petrol engine management ECU               £42.50 plus P+P

Diesel engine management ECU              £46.50 plus P+P

Auto gearbox control modules                  £59.50 plus P+P

VAG DSG mechatronic units                   £70.50 plus P+P

ABS modules                                         £44.50 plus P+P

Airbag control module testing, accident memory clearing £44.50 plus P+P

Range Rover BeCM units £50.50 plus P+P

BSi units £44.50 plus P+P

Mercedes combined MAF-ECM £65 plus P+P

Body Control Modules £44.50 plus P+P

Combi-instuments £42.50 plus P+P

Rover 75 Combi-instrument test fee is £45.00 plus P+P

Bosch VP44 PSG16 £69.50

Bosch VP30 PSG5  £49.50

Delphi-Lucas £59.50

Inspection/testing fee: Siemens-Denso-Sigma  £79.50

Bosch CDi version 3 common rail injectors testing £20.00 for each injector. Mail order customers, return postage & packing is £6.00 each per injector or £12 a set.

VAG PD injectors Labour charge for testing is £20.00 for each unit, return postage & packing is £7.00 per unit or £13 a set.   Land Rover TD5 injectors test fee £30.00 per unit

Prices for testing & repair of conventional diesel injectors.

Labour charge for testing, set of four injectors £40

Labour charge for testing, set of six injectors £57.50

Postage & packing is £8.00 for a set of injectors.

We do not ship back "dead core". Should you require unrepairable units returned please arrange a carrier to collect them!

All test results are reported via a phone call immediately after testing by the technician who enacted the test.