During the SELECT-A-MAP ECU development we discovered that the level of control it gave and the detailed fuel injection information it provided had tremendous diagnostic potential:

  • DPF FilterInstallation of the SELECT-A-MAP ECU, with a high power map, can identify partially blocked DPFs, long before the vehicle's ECU logs any errors or activates 'limp' mode. The test can be carried out simply by increasing the fueling (and consequently the exhaust gas volume) from the hand control. If this results in an EML or 'limp' mode activation, a partial DPF blockage may be present.


  • When used with a scan tool to assist with forced regeneration, we found that increasing the amount of fuel raised the DPF core temperature and accelerated the forced cleaning process.


  • During the forced regeneration procedure, while increasing fueling, if the core temperature should decrease rather than increase, it indicates that exhaust gasses may be leaking past the EGR valve, starving the DPF of oxygen (the core temperature reduces because there is insufficient oxygen to support the combustion of the extra fuel).
  • Following regeneration, if a high power map is selected during road testing, exhaust gas volume and temperature are increased, resulting in further passive cleaning of the DPF and also the full exhaust system.


  • Select-A-Map ECU Internal View

    A particularly useful feature for technicians who are familiar with oscilloscopes, is the ability to monitor injector current flow waveforms directly from test-points on the Select-A-Map circuit board. These are provided at 3 different stages of the signal processing: A 'raw' sensor input that can be used to verify correct injector current, an amplified (maximised to 5v pk-pk) signal that can be used to examine the injector current flow waveform in detail and a processed square wave representation of injection pulses that can be used for oscilloscope triggering and accurate measurement of injection durations.


  • Installer Hand ControlThe installer handset can display engine load value data that is directly related to fuel rail pressure and injection duration. This can be used as a comparative diagnostic feature to check the load values of the engine under test against known, good values. There is also a live acceleration data value that is useful for assessing not only the smooth running of an engine but also its acceleration rate. Again, this can be used to compare values of the engine under test with known values of similar engines to assist in diagnosing induction faults, mechanical faults and exhaust flow faults.
  • Real time fuel rail pressure data displayed in Volts, and assumed pressure in BAR, can be used to assess pump condition and fuel line pressure decay. Due to the fast refresh rates of the displayed data, it is possible detect problems such as injector leak-off.


  • Because the unit can be temporally and quickly fitted to a vehicle, it can be used as a selling tool to demonstrate to customers the performance upgrade potential of their own vehicle, whether they are considering a remap, tuning box or SELECT-A-MAP installation.

More diagnostic features are planned in future firmware upgrades.

Firmware upgrades are provided free* for 12 months after the purchase date.


* Select-A-Map units must be returned to CRD Technology Ltd for upgrades. Upgrades are free for the first 12 months but the customer is responsible for insurance and postal charges both ways.


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Chequered FlagsRemap Wins Every Time

A quick search of the internet (click here for an example) for advice and comparisons of diesel remaps vs diesel tuning boxes, reveals a near-unanimous opinion that the remap (also known as a ‘rechip’ or ‘chipping’) is far superior to any diesel tuning box.

Most people (except maybe diesel tuning box manufacturers!) will agree that a diesel tuning box is no match for a proper engine remap. And how could it be? – To map an engine properly, in accordance with engine speed (rpm) and load, it is essential to know what the engine speed and load values actually are at any given moment.

3D Fuel MapWithout such information, no diesel tuning box, however sophisticated it may be, can compete with a professional diesel engine remap.

A full engine remap performed by a reputable remap specialist, such as Superchips, Dimsport, Evolution Chips, Revo, ‘Tune My Engine’, MAS Performance, Elite Remaps, Celtic Tuning, Chip Tuners or TD Performance will always be able to out-perform any diesel tuning box in terms of performance, economy and drive-ability.

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So Why Would Anyone Buy a Diesel Tuning Box?

Wild ClaimsSince so many people agree that a remap will always be able to achieve a better balance of performance, economy and drive-ability than any diesel tuning box, why do so many ‘black box’ solutions exist and why do so many people continue to buy them and fit them to their vehicles? Do people really believe the wild claims made by some of the less reputable diesel tuning box suppliers?

Well, there are plenty of reputable diesel tuning boxes to chose from; Chip Express, The BHP Plus Speedhawk, the DTUK CRD2+ and CRD-T, the Tunit I, II, III and IV, the Synergy, the van Aaken Diesel Smartbox or the ‘Original TuningBox’, to name but a few. Even some of the more reputable diesel tuning box manufacturers have been known to get a little ‘creative’ with their fuel economy and performance claims, but few would be foolish enough to claim they can compete with a professional fuel remap.

Diesel tuning boxes vary greatly in sophistication and price, ranging from the cheap and crude ‘resistor in a box’ type devices, as sold on some auction sites, to the more sophisticated, microprocessor controlled devices that, in some cases, may be able to achieve moderately good results, despite lacking the accuracy and control of a fuel remap.

Of course one reason for opting for a diesel tuning box over an ECU remap is often cost. While it may be false economy, a diesel tuning box is often cheaper to purchase than a professional remap, giving the perception of being ‘better value for money’, at least in the short term. If combined with other factors, such as a design that facilitates easy installation or quick removal, this may be enough to persuade some people that a diesel tuning box is their best option.

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ECU Remapping – Problems and Risks

Vehicle ECUThere are, however, a growing number of vehicles for which a diesel tuning box is the only practical option. Improvements in vehicle engine management technologies, especially in recent years, have brought about an increase in processor sophistication and code protection securities that put conventional ECU remapping under threat.

While such complications do not necessarily make ECU remapping an impossibility, the increased difficulties and risks associated with such procedures can make the work extremely specialised and prohibitively expensive.Even if it is practical to carry out an ECU remap, there are a number of potential issues to consider:

If a remap can be performed without opening the vehicle’s ECU:

  • Will remapping be detected by dealer equipment and will it affect the vehicle’s warranty?
  • If an error should occur during reprogramming, could the ECU be rendered inoperable?
  • Could the new map be overwritten during routine servicing and dealer firmware updates?

If a remap cannot be performed without opening the vehicle’s ECU:

  • Can the ECU be opened without risk of damage?
  • Will the vehicle warranty be affected by opening the ECU?
  • Can successful remapping be guaranteed once the ECU has been opened?

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The Diesel Particulate Filter (DPF) Problem

For modern vehicles fitted with Diesel Particulate Filters, DPF blockage is a common problem. DPF regeneration should automatically clear the filter periodically, but it can only do so when conditions are right for the procedure to safely commence. Even factory standard vehicles running factory standard  fuel maps can suffer DPF blockage but the situation is made worse when the engine has been remapped or fitted with a diesel tuning box.DPF Filter

Diesel tuning boxes are particularly likely to cause DPF blockage since they lack the ability to control fuel in accordance with engine speed and load. Such indiscriminate increases in fuel can cause frequent over-fueling, with the result that particulates build up in the filter faster than DPF regeneration can remove them.

This is also true of an over-zealous remap, but even the most carefully and professionally executed remap can accelerate filter particulate build-up. Any diesel tuning box or remap that is permanently activated will accelerate DPF particulate build-up if it causes any increase in unburned fuel.

Some products, such as the Superchips Bluefin or the Dimsport Genius allow users to remap their own vehicles, a feature which could, theoretically, be used to help prevent DPF blockage by frequently reverting the vehicle’s ECU back to the standard fuel map. However, these devices reprogram the vehicle’s ECU so the procedure is not without risk and cannot be performed instantly, making it an impractical solution for the prevention DPF blockage.

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The Best of Both Worlds (and then some!)

So clearly an ECU remap provides the best results but involves procedures that can be fraught with problems and risks. Installation of a diesel tuning box, on the other hand, provides a far less risky solution but with typically poor results.What if it were possible to take the best of both and combine them into one unit? 

Diesel Control ECU


Imagine a device that looks like a tuning box, installs like a tuning box, can be quickly removed like a tuning box but is able to remap the fuel, taking into account engine speed and load, just like an ECU remap. Now wouldn’t that be the perfect solution!?

After years of research and development, CRD Technology have designed exactly that! The Select-A-Map ECU allows a vehicle to be remapped simply and safely without tampering with the ECU, yet it is quickly and easily installed, just like a diesel tuning box.

It provides not just one but FIVE fuel maps, instantly switchable via a remote key fob, and a host of other features not found in any other device.

It is also has a number of DPF-friendly features and the ability to switch to a standard or low power map when a higher power map is not required, helping to reduce any risk of DPF blockage to a minimum.

The solution is Select-A-Map!

Read more about the features and benefits of Select-A-Map here.

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Technical Information

For those of you who are technically minded and would like to know more about how the system works, click the link below
to either view or download the full operator manual of the Diesel Control ECU.

Diesel Control ECU – Operator Manual

View Manual Online

(Opens in a new window)

Download Manual

(PDF format – 1,950 KB)

Investor Opportunity

CRD Technology are currently seeking investment for global expansion.

Please contact Bert Clegg for further details.

Diesel Particulate Filter (DPF) Friendly

DPF FilterMany modern cars are vulnerable to DPF blockage, especially when they are subjected to driving conditions that are incompatible with automatic DPF regeneration.

For example, if the car is mainly driven in slow moving traffic or used for short journey commuting, where the engine is rarely subjected to the driving conditions necessary for effective DPF regeneration, a build up of particulates in the filter can occur, ultimately leading to blockage.

The problem may be exasperated by overzealous engine remapping or crude ‘diesel tuning boxes’ which can increase the amount of unburned fuel entering the exhaust system in the form of particulates.

The result is the inconvenience of frequent trips to the dealer for ‘forced regeneration’, which may be a chargeable job.

The Select-A-Map ECU reduces the risk of DPF problems by allowing any increase in fuel to be governed by engine speed and load so that fuelling can be accurately controlled to reduce particulate emissions to a minimum. Uniquely, with 5 instantly switchable maps to choose from, it is also possible for the Select-A-Map ECU to be configured to automatically default to a standard or more DPF friendly map under normal driving conditions, allowing any of the enhanced performance maps to be selected only when needed.

DPF Removal

An additional plug-in emulation module is also available for use with the SELECT-A-MAP. This will appease the engine management system of most vehicles and prevent them from going into limp mode, if the DPF were to be removed.

Rolling Road plot showing diesel mapping capability

The SELECT-A-MAP ECU offers the driver a choice of maps that can be switched in an instant, allowing power to be increased only when needed, therefore reducing fuel consumption and further reducing any risk of DPF problems.

High Torque and Higher BHP

High Torque and Lower BHP

Standard Torque and BHP

Rolling Road Plot
Select-A-Map - Diesel Remap ECU

The world's most advanced diesel performance computer

The SELECT-A-MAP Diesel Control ECU is a new generation, diesel control computer that is undoubtedly the most sophisticated and advanced tuning product available anywhere.
Click here to view or download the brochure

A complete fuel remap with all the convenience of a tuning box

Select-A-Map ECU The Select-A-Map ECU is quite simply a revolution in vehicle remapping. It combines most of the benefits of a conventional diesel ECU remap with the ease of installation of a diesel tuning box. It is designed to be highly universal, making it compatible with most common rail diesel engines and it contains a host of other features not found in any other product.

The only non-intrusive remapping solution

Using patented technology, developed in the UK by the fuel injection experts at CRD Technology, the Select-A-Map ECU allows your vehicle to be remapped without cutting wires or making any modification to your vehicle's ECU. This not only makes for a quicker installation time, but also makes transferring to another vehicle possible and greatly reduces the risk of invalidating your vehicle's warranty.

Select-A-Map System Diagram – Click to Enlarge
Select-A-Map Block Diagram
Click here to view or download the brochure

Power, speed and accuracy

To maintain engine efficiency and reduce the risk of Diesel Particulate Filter blockage, it is imperative that any modifications to the quantity of fuel injected are precisely metered and timed. The Select-A-Map ECU achieves this by accurately monitoring fuel rail pressure as well as injector opening times, using a unique, non-intrusive injector sensing method. It performs many millions of calculations per second, enabling it to compute engine speed and load values instantly so that the exact quantity of fuel required is always injected at exactly the right moment.

Advanced Features

Using the same principle as a professional ECU re-map to create a mirror image of the vehicle's own ECU fuel map, the SELECT-A-MAP creates 5 different maps that are instantly switchable using the remote key fob with the ignition on or engine at idle. Select-A-Map Remote Control Key Fob

1) Standard Map

Standard torque and standard power.

2) Economy Map

Increased torque and standard BHP to enable optimum economy – Can be refined to operator's specific requirements.

3) Fast Road Map

Increased torque and increased BHP for everyday driving, while retaining good driveability and improved economy, with no adverse effect on DPF.

4) Very Fast Road Map

Tuned to give the highest Torque and highest Power for occasional fast road or track day use.
Note: Prolonged use of this map could result in more frequent DPF regeneration and, since it provides uncompromising levels of performance, fuel consumption will likely increase.

5) Reduced Power Map

Low Power or 'Valet' option enables already powerful cars to be used by less experienced drivers.

Any of the predefined maps can be used as is or, as an optional extra service, the installer can further refine any map* to suit individual requirements.

No single map is right for every purpose. Vehicle manufacturers are forced to compromise by producing a map that meets emission regulations while providing acceptable economy and performance.

ECU re-map specialists experience similar problems when working with a single map; improvements can be made in some areas but never in all areas.

By offering 5 customised, instantly switchable maps, it is possible to provide an uncompromising solution that can be tailored to suit any purpose and every customer.

Some re-mapping companies offer customers an optional OBD handset that allows switching between 2 maps, but this procedure can take several minutes to perform and carries a risk that a data error could render the vehicle's ECU inoperable.

A specific map can be selected as the default map to revert to at power-up/ignition-on. For example, it may be preferable to always start the vehicle with a standard/100% map or, for added security, a reduced-power or ‘valet mode’ map. Note: One exception to this is Map 5 which, when selected, remains selected, regardless of any default map settings or ignition status, until a different map selection is made.

* Additional mapping costs may be charged.