FreeScan Site_

FreeScan v.2.1.0
supports all 4-Cylinder Lotus Esprits models with GMP4 DELCO Fuel-Injection.
Installer can be downloaded from here

(Superior diagnosis to anything a Lotus Dealer may possess)


Freescan Prog

FreeScan is a windows-based program that is able to communicate with the ECU which controls all 4-cylinder Lotus Esprit models built between 1989-1999 (SE, S4, S4s, GT3). These cars were all fitted with the GMP4 Delco fuel injection. This software can help with tracing problems with your Esprit including reading internal error codes and also making sure everything in running as it should. Many Esprit's are currently running at less than 100%, don't let yours be one of them. This software is a must for all Esprit owners with GM Fuel Injection.

FreeScan runs under most Windows platforms (especially 95, 98 and NT4), it needs 800 x 600 minimum display resolution and one free serial port. It is recommended to have a 90 MHz or better Pentium and at least 32 MB of RAM. You will also need an interface cable that connects your PC serial port to the GM ALDL port. The data is in TTL (i.e. 5V), bi-directional (half-duplex) format and runs at 8192 bps. All you need to run FreeScan is available at the Club Esprit E-shop.

Several years I wrote Version 1.0 of a FreeScan manual and trouble shooting guide. Kato at LEW has helped turn this in a very professional looking manual and together we now offer a number of options.

Lotus Esprit World (LEW) will supply you with everything you need to communicate with your Esprit's ECU via your laptop. Click on picture below to take you to the LEW E-Shop.





4-cyl Diagnostics Packages Available from Lotus Esprit World

Full FreeScan-USB Package

For all Injected 4-cylinder Esprit's

This package contains the FreeScan software, high quality all-in-one ALDL-USB-Serial adaptor, drivers, and 36 page FreeScan Manual. FreeScan can hook you up via your USB laptop connection to read the coding from your ECU. Perfect for troubleshooting and also includes free diagnosing of your log files and future updates. Read more here

£145 + p&p
(p&p = £4 UK, £5 Europe, £7 US, £9 Japan)

Serial FreeScan Package

For all Injected 4-cylinder Esprit's

This package contains the FreeScan software, high quality ALDL cable and 36 page FreeScan Manual. FreeScan can hook you up via your laptop to read the coding from your ECU. Perfect for troubleshooting and also includes free diagnosing of your log files and future updates. Read more here

£95 + p&p
(p&p = £4 UK, £5 Europe, £7 US, £9 Japan)

FreeScan Manual

For all those with an ALDL Cable

This 36 page manual will help you get the best from FreeScan. Includes colour pictures, graphs, troubleshooting and a full guide to all FreeScan facilities. So if you already have a cable, this manual will help make sense of all the data. Available in both printed paper and PDF format. Price includes updates and log diagnoses. Available in pdf format at this reduced price.

pdf copy £15
hard copy
£19 + p&p

(p&p = £1 UK, £2 Europe, £4 US, £5 Japan)




Online Help and Latest Developments

I intend to use these pages to post continuing developments of Freescan and additional user support.

New USB-ALDL Interface (Sep 2007)

Modern laptops are no longer build with RS232 serials ports. We have now have USB-ALDL combined interface lead. The lead come with drivers for all Windows OS including Vista. We have been testing it now on a number of laptops and it seems to offer a good working solution.







The lead has the interface and the USB-serial chipset all build into the plug. It also has a 5 mm jact adaptor for ease of conencting to the car.

These leads are now available from Lotus Esprit World E-shop. Click Here


USB-Serial adaptor

We certify only one USB-Serial adaptor solution with the ALDL interface cable. This development will allow all users upgrading to laptop PC's that just have USB ports to have the old ALDL-serials interface leads. It have been tested on all windows systems even Vista. I will be distontununing this adapters once the stock is gone in preference to the all-in-one USB-ALDL interface above. Still available on the LEW page above.











Log Files (27/12/04)

Freescan Users are very welcome to email me their log files for diagnosis. I will try to look at them within a day or on the same day and give you some feedback.

USB-ALDL Support — Update (7/4/05)

We are currrently working on an intergrated ALDL/USB solution for USB only PC's. It will require no additional hardware or adaptors.

Modern laptops are no longer build with RS232 serials ports. If you have a laptop with just USB ports then you will require a USB-RS232 adapter to plug into to the ALDL interface. When Freescan was originally developed USB protocols were not considered. In the Freescan manual we have not developed or tested any USB-RS232 adaptors.  It is a complicated problem and I have yet to see a foolproof solution. One of the issues I have discovered is that although a number of manufacturers offer USB to RS232 adapters - what works on one computer may not work on another.

Some people have commented that the Belkin F5U103 USB to RS232 adapter works. While others have tested it, and it would not work for them. The AKM USB to RS232 adapter is being designed around the FDTI FT232BM chip. The only 'gotcha' - it will be all surface mount component, so the 'kit assembly' will not be something the average guy can put together Here is the link:

The USB to serial adapters are all over the map as far as quality goes, and some of it depends on which operating system you have. Unfortunately, it might be  a trial and error thing for you. A serial connection is full duplex, meaning that it can transmit and receive at the same time. A USB connection is half-duplex, meaning that it can transmit or receive, but not at the same time. So, when an adapter is made and it's corresponding drivers are written, a  translation has to be made between these two types of communications. Some USB adapters do this better than others. Unfortunately, I can't tell you which to use, because it's dependent on which operating system you are using as well as the software and hardware you are trying to connect with.

The correct way to do this is with a serial to PCMCIA card. These exist but are quite a bit more expensive than the USB adapters. The PCMCIA cards do not have to do any translation and are full duplex. They will work without any problems.

 Further Developments(27/12/04)

The Installer we are mirroring was developed several years ago by Andy Whittaker. Although still maintains a website he is no longer an Esprit owner and so is NOT supporting or developing the software further. Andy has now made the source code available. If anyone is interesting in continuing to develop the code I would be delighted to hear form you:



For those totally unfamiliar with all of this so far. The software we are talking about is superior to anything a Lotus dealer has. The software can log to hard disk the following parameters. This can then be analysed offline to give you a very comprehensive picture of the general condition of your engine and its overall performance.


FREESCAN can log the following ECU parameters.

Esprit Sample: Data Reference point.
Coolant Sensor V: Coolant sensor voltage.
Start Water Temp: Starting temp on engine switch on.
TPS V: Throttle position sensor voltage, typically 0.49 V at rest and 4.0V at 100%
Des Idle: RPM that ECM is trying to control idle speed.
RPM: Engine speed.
Road Speed: Road speed (MPH or KPH).
Crank Sensors: Reference pulse.
O2: O2 sensor voltage ranges form 0.01–0.9 V. Readings below 0.3V is lean, values above 0.5 V is rich.
Rich/Lean: Rich-lean voltage swing in the O2 sensor output.
Integrator: Normal reading around 128, The integrator is a short term corrective action which the BLM values are set.
BLM: Values vary between 80-130.
BLM Cell: There are 19 cells which the ECM learns, depending on RPM and MAP.
Injector Base PW: Duration in msec that the injectors are open.
IAC: Idle Air Control, system used to control engine idle speed.
Baro: Barometric pressure, typical about 0.84.
MAP: Manifold Air Pressure. Max value 2.24 which is approx 1.1 bar.
A:F: Air/Fuel ratio.
TPS: throttle position (%).
MAT V: mass Air Temperature senor voltage.
Knock Retard: ignition retard in deg as a result of knock detection Spark .
Knock Count: engine detonation counts.
BatV: Battery voltage detected by ECM.
Load: Engine load
Spark: Ignition advance in degrees.
Coolant Temp: Coolant temp in deg.
MAT: Mass Air Temperature (°C)
Wastegate DC: Wastegate solenoid % duty cycle .
Secondary Injectors DC: secondary injector % duty cycle .
Engine Running Time: Engine running time since switch on.
A/C Demand: Air con is on
A/C Clutch: Air con is on
Closed Loop In closed loop: ECM controls engine running using the O2 sensor feedback.


Parameter Units Typical Data Value (Range) If Data out of Range Refer to…
Engine Speed: RPM 0  
Desired Idle: RPM Depends on coolant temp  
Coolant Temp.: °C Close to ambient Code 14/15
Mass Air Temp: °C Ambient Code 23/25
MAP: kPa Close to baro Code 33/34
Baro,: kPa Dep. on attitude, ca. 0.85 Code 31
IAC,: counts 170  
Throttle Position: V 0.4-0.7 Code 21/22
Throttle Angle: % 0 Code 21/22
Oxygen Sensor: V Approx 0.455 Code 13
Injector Pulse Width: msec Depends on coolant temp  
Spark Advance: deg. 75  
Road Speed: MPH 0  
Fuel Integrator,: counts 128  
Block Learn (BLM): counts Not valid  
Block Learn Cell: Cell # 19  
A:F:   Not valid  
Open Closed Loop: 1 or 0 Open loop  
Knock Retard: deg. 0  
Knock Signal,: counts 0  
Battery Voltage: V 12.0 Check battery
A/C Demand: On/Off No  
A/C Clutch: On/Off No  
Time From Start,: sec number  


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