HOMEPAGE               

Page index

1. What do I need

2. Scantool software

3. Rover compatibility list   

4. Experiments with Vagcom

5. Sykes Pickavant ACR4 Code Reader - NEW

INTRODUCTION

On Board Diagnostics and our European On Board Diagnostics (formerly called OBDII) originated in the USA as this quote from their Environmental protection Agency shows.

"On-Board Diagnostics, or "OBD," is a computer-based system built into all 1996 and later light-duty vehicles and trucks, as required by the Clean Air Act Amendments of 1990. OBD systems are designed to monitor the performance of some of an engine's major components including those responsible for controlling emissions"

OBD is accessed via a 16pin connector - the DLC (Data Link Connector) aka diagnostic socket.

This has to be sited close to the drivers footwell, so sometimes it is behind a lift up flap low down on the dash, or in the case of the 45, it is at the front of the centre console on the drivers side near the clutch pedal.

All petrol vehicles sold in the USA from 1996 had to have this socket and fully implemented OBD. This means those never destined for the USA may be, may partially be, or may not be compliant at all. In Europe petrol vehicles from 2001 and diesel vehicles from 2004 had to be compliant.

Please note, pin 16 is permanently at battery volts and only a few of the positions will be fitted with a contact.

Faults which affect the emissions result in a fault code - a DTC (diagnostic trouble code) being logged by the ecu, which can then be read out to determine the problem and possible cause. 

Serious faults also turn on the check engine light/engine warning light, more correctly known as the MIL (Malfunction Indicator Light) to indicate that you should take the vehicle to a dealer for attention. 

Very serious faults affecting safety or resulting in engine damage can also cause a reduction in power - so called limp home modes. These vary from just a moderate lack of power & reduced rev limit to almost complete power loss - with just enough to crawl home or to a garage at 30mph. 

Here is my experience of limp home mode!

My 2000 45Tdi and 2003 45 Impression S 115 TDi are not officially OBD compliant. However, the connector is fitted & I found that they output the sensor data listed below. 

See below for a list of Rovers which will work with the Scantool interface. Please email me with your findings if you have tried any sort of diagnostic tool.

A) Listing and clearing DTCs & resetting the MIL. SOME ROVER MIL HINTs are HERE

You can identify the DTC & what has caused it, clear it & reset the MIL  if your vehicle is fully EOBD compatible.

On fully compliant cars, you can also examine the 'freeze frame' data. This is a snapshot of the sensor data at the instant the DTC was logged by the ecu.

This is a list of modes which should be supported. Often not all are, even though the software can appear to support all of them. 

In other words, just because the software reports no DTCs, doesn't mean there aren't any. Only if your vehicle is reported as being OBD COMPLIANT, should you believe exactly what you see! For example, when the throttle position sensor failed on my previous 45 TDi, the software said there were no DTCs, that the MIL was off  when it was on and there were in fact 4 DTCs logged!

01    SHOW CURRENT DATA including OBD compatibility

02    SHOW FREEZE FRAME DATA  - sensor data at the time a DTC was logged.

03    SHOW STORED TROUBLE CODES

04    CLEAR TROUBLE CODES AND STORED VALUES - also may reset learned values.

05     SHOW TEST RESULTS - OXYGEN SENSORS - CONTINUOUSLY MONITORED

06    SHOW TEST RESULTS - NON CONTINUOUSLY MONITORED 

07    SHOW PENDING TROUBLE CODES - faults that have been detected but have not recurred enough times to be a 'current' DTC.

08    SPECIAL CONTROL MODE - often used to activate idle steppers, egr valves etc. 

09    REQUEST VEHICLE INFO - eg VIN etc

ON PETROL MODELS, MORE SENSOR DATA CAN BE VIEWED - EG 02 SENSORS.

C) TESTING YOUR ENGINE MODS.

Perhaps one of the neatest uses is to test engine mods. Anything you alter should show up on one or more sensors.

For example, if you increase the air into the engine you should see this in the MAF readings. If you 'up' the boost pressure the MAP readings should reflect this. If you log the data & then plot it using Excel, you can see where in the rev range the changes are occurring. As the time is also recorded when you log anything, you can measure the effect on the performance. See the MAFAM page for a chart example produced from the OBD Logger's data.

NB the sampling rate is only about 3-4 samples per second so the more sensors you log, the fewer readings per second you get. I.E. if you logged everything you'd only get about one reading of each sensor every 2-3 seconds. This means for greatest accuracy, log as few parameters as possible. Although some OBD programs have performance measuring features - eg 0-60 or standing 1/4mile, due to the slow refresh rate, the results are not accurate though they could be useful for before/after comparisons.

You need an ISO interface for a Rover and some software. (There are different versions as different manufacturers use different protocols.)

The most popular DIY interface is a Scantool ISO Interface available from Gendan.co.uk. This is supplied with all necessary cables & connects to the serial (com) port on a laptop or PC and to the car's 16pin diagnostic socket.

BUT NOTE, a mod is required since MGR missed a pin out of the connector! SEE HERE 

This interface uses a single chip microprocessor from ELM Electronics and there are several programs which are compatible with this chip. See below for a list.

There are others interfaces however.

A dumb type is available from SK Pang which, for non VAG vehicles, only works with Vehicle Explorer version VE116CT software from OBD-2.com - not freeware.

But it will also work with many VAG vehicles using the freeware version of VAGCOM from Rosstech.

Recently, the July/August issue of Elektor featured a kit of parts for £54 that uses the Ozen Electronics chip and works with a special version of Scanmaster. This will be tested soon.

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There are several programs that will display the data & some that will log it for later examination. All the software that works with Scantool (or any other ELM based interface) has the same capabilities - its mainly the user interface and display format which differs.

Here are some screen shots:

Various shots of Scantool, Digimoto & Scanmaster. 

Here are 3 screen shots thanks to Craig L, from his 2003 ZS180 using my Scantool Iso and Scanmaster.

OBDlogger reads the data in sequence, so the more parameters you log, the slower it is. Usually I just log 3 at a time when I'm doing performance testing. Digimoto also has a logging feature. 

Logging the data in .csv format means you can import the data straight into Excel as I did for this test and then plot it.

Dashboard screen shot from Scanmaster - you can choose what to display. Its early days, but there's definite potential for experimentation with a 'carputer' here.

I prefer Scanmaster and Wobd.

SCANTOOL COMPATIBLE SOFTWARE LIST.

Suggestion for programmers.

Please, please assign the spacebar (or a function key) to start and stop the data logging. Have you ever tried using a laptop pointing device in a moving vehicle? In fact, more function key controls and less use of the mouse altogether please for these applications!

The Scantool interface needs a minor mod to work with some (if not all) Rovers. This is because Rover forgot to connect pin 5 of the OBD socket. click here for full details & pics.

Please checkout the excellent FAQs, forum & support pages at Scantool.net or email me & I will try to help.

Digimoto needs everything connected & the ignition on BEFORE you run it. If not, of if you turn the ign off, you may have to reboot the laptop. Just trying to restart Digimoto doesn't always work - it seems to get so far through the initialisation then hang. Its a big disappointment.

With OBD Logger, setting the speed slider to high (to the left) will give "communications lost" messages. For greatest accuracy, select as few parameters to log as possible. So if logging performance times, for example, just choose speed, and also just choose EITHER text or CSV - not both.

Prior to 2001 for petrol and 2004 for diesels, manufacturers were not required to make their vehicles fully compliant. Many therefore used their own codes for both accessing the ecu and for some of the fault codes. Some professional code reader manufacturers have been able (probably at great expense) to obtain the manufacturers specific data and produce tools which will work as well as Rovers own laptop based Testbook. For example, pods are available for Sykes Pickavant's ACR 2 and ACR4 code readers that cover most Rovers. In fact their latest Rover 4 pod covers them all.

Because many professional code readers are compatible with most Rovers, there is NO NEED to pay a MGR dealer £70 when an independent garage or vehicle diagnostic centre will charge £20-30 to give you the list of codes and reset the light.

Here is a list of generic codes (P0xxx). These apply to all manufacturers. But the P1 codes are manufacturer specific and in Rover's case, they won't divulge the details

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1. 2000 45 Diesel. Read and clear codes - NO. Turn off the MIL - NO. Read sensor data - YES
2. 2003 45 Diesel. Read and clear codes - NO. Turn off the MIL - NO. Read sensor data - YES
3. 2000 45 1.6i. Read and clear codes - YES. Read sensor data - YES
4. 2003 ZS 180 list & clear DTCs - yes. Reset the MIL - yes. Scamaster screens shots to prove it works: 1  2  3 

EXPERIMENTS WITH VAGCOM. VAGCOM MAIN SCREEN

WHY BOTHER?

Well, I still haven't found why Scantool can't list and clear DTCs, whereas professional code readers can,.

So thinking it may be due to a limitation of the ELM chip in the Scantool interface, I thought I'd try a different approach.

Vagcom is the well known & powerful VAG diagnostic software available from Rosstech.

After all Rovers use the same Bosch components as many VAG models. However, VAGs, although using an ISO hardware interface, use a different protocol - namely KWP (Key Word Protocol).

Current versions only work with their interfaces, but their original interface used opto couplers. I already knew that only the K line is used on the 45, so only 2 opto couplers would be needed. (The L Line part of the circuit can be ignored)

After building one (£15 in parts of which £9 was for the diagnostic plug) and downloading the freeware version of Vagcom, I was keen to see what happened! Nothing ventured, nothing gained as they say...

Vagcom has an OBD test option, and more importantly, the useful feature of being able to automatically scan for upto 127 controllers.

IT WORKED - up to a point.

Vagcom passed the ecu as being OBD2 compliant, and then over the space of an hour, found the following controllers as the screen capture shows:

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USING A SYKES PICKAVANT ACR4.

I recently acquired a ACR 4 code reader with Rover 4 pod and cable. This pod is compatible with all Rovers including Mems, all diesels inc D, di, 25/45 & 75. It can also test the ABS, & SRS and reset the 75s service light.

Needless to say it showed 3 DTCs - but ones I caused deliberately when trying to get the Scantool software to work. The codes were 0257, 1402 & 1218. Which are the map sensor unplugged, egr solenoid  unplugged and no1 injector needle lift sensor unplugged. 

There were NO codes caused by or related to the Mafam that I've been using for a couple of months nor any due to the boost pressure having turned up to 20psi. I've checked the car weekly since, and never had any codes.

I've taken some shots of the 4 line display. The ACR 4 can also test actuator such as fans, egr valve, glow plug relay, a/c clutch and turn the MIL on & off.

It can also display a lot more data such as fuel value, accelerator pedal volts, sensor supply volts, egr flow %,  - these aren't available through the scantool interface.

Clearly,  manufacturer specific information is available with this that can't be accessed  with a generic OBD (diy) code reader.

This is the initial screen after plugging it in. 

Its powered from the DLC (diag socket)

After you've chosen the engine type, you then select the ecu type:

EDC15M, MSA11 OR DDE4 for the 25/45, Sdi and 75 respectively.

It then confirms that it is talking to the ecu and then gives you this screen....

The actuators menu lets you test things like the egr valve solenoid, heater plug relay, a/c clutch, MIL light.

If there are fault codes, then you read them from this menu.

I also found out why diy and generic code readers don't work with the L series. I.E. why only mode 1 commands are recognised.

Its because the ecu requires the code reader to request security access (mode 27). When it does so, it receives a seed which is converted by an algorithm within the code reader into a key. This is sent to the ecu which compares it with its own calculated key and if they match, access is granted. The seed is generated randomly at each access request. Once access is granted, the standard diagnostic modes work and some Rover specific ones are also used to test actuators and display more advanced sensor data. Eg fuel quantity, % egr flow, tps voltage, sensor supply voltage etc. The ecu also uses in-frame responses - which no ELM chip based scan tool support. (The Elm chip is limited to 7 data bytes)