Scan Tools, TestBooks and Computer Code Access Tools

TestBook and T4
Aftermarket TestBook/T4 Alternatives
OBD-II Scanners
Home Made Solutions

(Photo: Autologic System, courtesy of Atlantic British)

Testbook and T4:
The coming of the P38 model with its all-pervasive electronics and dozen or so ECUs brought with it the advent of the "Testbook" made by Hewlett Packard, which dealers use to access the fault codes and other information for such systems as the air suspension, cruise control, transmission, ABS/traction control etc etc. This system consisted of a ruggedized notebook computer with a touch screen, a cable and connector for the 16-pin OBD-II compliant connector under the glovebox, and suitable software. It accesses many more vehicle functions than standard OBD-II systems -- anything that is computer controlled, which is nearly everything -- the engine, transmission, transfer case, suspension, BeCM, ABS, cruise control, and on and on. Originally, the system was not even available to anyone outside the dealer network, making it doubly frustrating when you run into the notation "Refer to Testbook" in the factory repair manual.  Originally costing $30,000, the Testbook system was well out of reach of most independent shops, let alone individuals.

When Hewlett Packard got out of the automotive diagnostic business in 1999, Land Rover contracted with another company, Omnitec, to produce a more upt to date system called the T4. Due to legislation in the US forcing auto manufacturers to make their technical and diagnostic information available to independent shops as of October 2003, the T4 system is now available to the public through Omnitec as their "T4" diagnostic system. The cost is £7,785 or about US$12,000. Also available from them is an optional hand held T4 tester covering 99-on models.

Aftermarket Testbook/T4 Alternatives
The unavailability and outrageous cost of the Testbook system created a market for independent firms to develop their own diagnostic software by reverse engineering the Range Rover system. These are sold less expensively -- in the $2,000-10,000 ballpark, and the main contenders are the Autologic Diagnosis System and the Rovacom system, both from the UK.

Autologic Diagnosis System:
The Autologic Diagnosis System is another aftermarket TestBook equivalent from the UK.  In the US it is available through Atlantic British, who also provide training seminars on its use. Aimed at local garages rather than individual owners, the complete system (costing significantly less than the T4 system) covers all late model Land Rovers. It includes extensive help pages and internet updates. (See photo at top of this page, courtesy of Atlantic British). 

Black Box Solutions:
The Rovacom system by Black Box Solutions was the first aftermarket equivalent for the "TestBook" to become available, and was claimed to be even better than the TestBook. It was certainly more portable. It used a rugged custom case and hardware with a 12 inch touch screen, and drew its power from the vehcile's diagnostic connector or a 12 volt jack. The unit came with all the software installed for the various Land Rover models, but you could pay for only the ones you wanted activated. The basic unit with no software activated was about £2,000.  Thus, you could get a system customized to cover all the systems on your particular Range Rover P38 for about £3700 ($6,000). Black Box Solutions later started selling used Rovacom units for up to 50% off, bringing them down to the £4,500 range ($7300) for units with software activated for all models. In the US the Rovacom system and its descendants is available through dealers including Rovers North (email@roversnorth.com and ask for Arthur or George) or British parts International (Phil Prince, Phil@britishparts.com).

OBD-II Scanners
The Range Rover 4.0/4.6 complies with the OBD-II standard and ISO-9141. OBD-II scanners are now available for $100-200 and plug into the 16 pin connector under the passenger side dash. Although it will not tell you everything the dealer's $15,000 "Testbook" does, it can give you a lot of information about the  engine and transmission fault codes specified by the OBD-II standard -- for example it will tell you why that pesky "Check Engine" light has come on. One low cost system is a $122 OBDII Automotive Scan Tool Browser for your notebook computer is available from Alex C. Peper, 67 Scotch Pine Dr., Islandia, NY 11772, complete with OBD-II connector and cable. Partsamerica.com sells the hand-held Equus 3100 OBD-II code reader for $114.99. Actron makes a convenient hand-held scanner that works on all American and Import OBD-II vehicles and is sold through JCWhitney.com for about $159. The same vendor also sells low cost scanners from Auto X-ray and Equus. Danny Ledford reports that TRW has a scan tool called the Laser 2000 that is very affordable. He says it does engine management, ABS, and electronic air, and works on new OBD-II and older serial ports. Tradervar is another low cost source of scan tools.

For more information on OBD-II scanners, software and gear see the RangeRovers.net Diagnostic Equipment forum.

Home Made Solutions
Ken Metcalf has a '93 RR with air suspension which he bought (cheap) with the Air Suspension on the bump stops and the ECU in fault mode.  He has been chipping away at arranging his own "Testbook" to deal with this but is still trying to figure out the VCSI (Vehicle Serial Communications Interface) and cable that goes between the serial port on the computer and the Air Suspension ECU. He thinks that the VCSI is an ISO9141-2 box with K line and L line outputs but it is not clear which connects to which pins on the diagnostic connector.  Another puzzle is that the Rover cable between the VCSI and the ECU has a push button that initiates communication.

IN 2004 Ken offered the following notes on his efforts to figure out the system: "I am still trying to unravel the puzzle of how to interface an ordinary PC or notebook (loaded with Testbook software) to the Air Suspension ECU on my '93 RR Classic.  But I am sure that once access to one of these systems is figured out, the rest will be plain sailing.  For what it's worth, here are some of my observations (with regard to the Classic Air Suspension ECU - take them at your own risk! ): - External to the PC/Notebook (and connected by a special serial cable) is the VCSI (Vehicle Communications Serial Interface), which then connects to the ECU with another special cable that has the appropriate diagnostic connector.  Testbook hardware information only says that the VCSI conforms to ISO9141 standard and can achieve a baud rate synchronization from 10 to 10K baud. 

"The physical drawing (i.e. a picture, not a schematic) of the cable that connects the VCSI to the ECU terminates at the ECU end with a diagnostic connector, a hand -held push button and a wire with an uninsulated alligator clip on it (probably for connection to chassis ground). When you look at the Testbook software loaded on a PC, it says to push the hand-held button to begin communication.  Looking at the other cables and connectors used for the various ECU's, it is only the Air Suspension that has this push-button arrangement to start communication. ISO9141 uses two communication lines a K line and an L line - although mostly just the K line is used ("single wire communication").  This leaves me to speculate that the L line is routed through the push button and is only used to "wake-up" the ECU.  The ECU has two pins for connection to diagnostic equipment - pin 17 and pin 35 - which pin is the K and which is the L, is not clear; although pin 17 has wire colour abbreviation "WK" and pin 35 is "WLG" - this is either: 1) a clue, 2) a red herring, 3) a coincidence - take your choice!  Take note, however, that the diagnostic connector for the fuel injection ECU also uses these same peculiar wire colour codes, and the ABS has a "WK".

"The big problem now is figuring out the VCSI and it's protocol, compounded by the fact that any ECU built before 1996 is pre-OBD2 and can have any one of a number of unique protocols.  There is a very active forum at www.scantool.net - do a search on "ecu" or "range rover" in the forum and you will see that that there are a number of people chipping away at this.  On this forum was posted a link http://members1.chello.nl~t.bloem/defender/testbook/testbook.html that supposedly shows the diagram for the original Rover VCSI, but it is in German and seems to be the usual opto-isolator type ; also it is for the more modern vehicles that have diagnostic connectors that conform to OBD2.  www.elmelectronics.com is somehow associated with scantool and their site makes interesting reading too. Jeff Noxon has designed a very simple RS-232 / ISO9141-2 optoisolator interface - the details are available free online.  Ross-Tech is another good source of information on OBD".

Meanwhile, Ken reports that you can purchase Rover Test Book software (that will go on an ordinary PC) for US$250 at www.the-land-rover.com  - look under "Manuals - OBD".  Bruno at www.the-land-rover.com says that they are working on a DYI kit for the VCSI.  Jeff Noxon has designed a very simple RS-232 / ISO9141-2 optoisolator interface - the details are available free online.  Ross-Tech is another good source of information on OBD".