ECUs - Alvin Booth
With all cars nowadays having ECUs what do you independant garage owners or mechanics do when you need to diagnose engine or other faults.
Is there such a thing as a common diagnostic tool which can be adjusted to suit the paramaters of all cars, or do you have to take customers cars to main dealers with the manufacturers supplied equipment.
ECUs & Computers - David Lacey
Even us dealers with the 'correct' test equipment sometimes struggle to deal with todays complex cars.
We have one car off the road with a software glitch - probably one line of data with an incorrect figure causing the Traction Control Warning light to stay on.
Cars are becoming far too complex.

In response to Alvin's query - Yes, there are scan tools out there with interchangeable pods to allow testing of different systems using the same basic scantool. Most use the industry-standard J1963 diagnostic connector. Makes life much easier. The difficult part is trying to find these damned daignostic connectors!!

Re: ECUs & Computers - Alvin Booth
having read all the posts on how easily it is to upset the codes etc on these ECUs by carrying out the simplest of tasks it frightens the DIY man to carry out the simplest tasks.
For instance I recall one saying that simply removing the battery can give problems. Just what can be done without causing havoc. For instance I was about to fit a switch to enable me to turn on the radiator cooling fan manually.
Can cutting into wiring to re-route etc cause any problems.
And what about jump leads and chargers etc.
Just what should we not do anymore with this over the top unwanted technology we have landed ourselves with.
Re: ECUs & Computers - Dave N
You can get various devices to read ecu's, but they don't always show a fault, even when you are sure there is one. Most specialists keep spare good ecu's, and the first thing they do is swap it to see if it make any difference (before charging the customer). Things like the late range rovers have seperate ecu's for everything, cruise, climate, abs, body control etc. Problem I have is with climate ecu's, as I can't hope to carry spares for everything that comes my way, and some of the tools available don't cover climate ecu's. However, more of these functions are now being incorporated in one single ecu, which in theory, should be easier to diagnose. The other problem is that manufacturers are constantly updating the software, so even if you have a spare one, it may not have the latest version.

You are also correct about some simple tasks that may ruin ecus, especially disconnecting (or flat) battery, and jump starting. Simply because of the sharp voltage spike that can occur in these situations can bust delicate electronics. I always avoid disconnecting the battery wherever possible, and am very careful when probing around in plugs and sockets as you can supply voltage to components that are not designed to take it. An example is the pressure sensor on BMW a/c. It used to be just a switch that passed the power to the compressor if there was sufficient pressure. If the switch was suspect, simply jumper the socket. Now though, it is supplied with power, and a set resistance is sent back to the ecu (depending on pressure), the ecu then sends power to the compressor and fires up the fan, which has a variable speed facility, depending on the pressure. If you jumper this, you shoot a straight 12volts to the ecu, and bang!, nothing works again. This same principle is used for the engine temperature. In the old days a switch turned it on, but now it starts turning very slowly, and rises as the engine temp rises, and vice-versa.
Re: ECUs & Computers - Andrew Hamilton
My 1990 LDV 200 diesel van has no ECU or catalyst. Similarly my mothers 1983 auto metro has easy to understand mechanical distributor. Save money buy secondhand in the bargain basement pre-1993(no catalyst).
Re: ECUs - Darcy Kitchin
Our local Halfords has a complete section devoted to the paraphenalia for reading ECU fault codes from different cars. Looks like the ordinary punter can throw loads of money at buying a suitable collection of kit.

Long live the non-ECU diesel!
Re: ECUs - Mike Wolstencroft
wouldn't be so bad if all this new gizmo stuff had resulted in more reliable cars - but it hasn't - does your car have a speedo cable? The little smart device which VW installed on the Golfs to generate whirly amps to drive the speedo is a classic piece of built in irritation - expensive to replace and inaccesible to boot. How many times has some poor unfortunate been charged with the price of a replacement ECU when all that was required was cleaning the connections TO the ECU. Conclusion - the dumbing down process continues.
Suggestion - why not just weld the bonnet shut at birth and save the (high) cost of main agent servicing i.e cost of three services = exchange engine unit replacecment at, say 60 000 miles - the fleet operators would just love that, I'm sure.
Re: ECUs - Alvin Booth
It begs the question why have we had these gizmos foisted upon us. I imagine the main reason is to enable manufacurers to conform to EU legislation on exhaust emissions which would appear to be reasonable.
However they appear to have gone way over the top with these gadgets.
For instance my car has no accelerater cable and apparently works through a potentiometer. The windscreen wipers regulate their speed in relation to the speed of the car. Who wants these designers whims.
And why should a ECU cost so much money. In these days when you can buy a computer with monitor, sound cards, modem and so on for much less than a ECU surely they should relate to the same thing. After all they can't be much more than a motherboard and memory chips encased in a box so why the big deal. Why hasn't the market place dictated the cost of these as in the computer world. I would have foreseen us going into our local motor accessory shop and asking for a Astra CPU. That will be £20.00 mate says he.
Some have just come in from Taiwan.
Are they only available from main dealers or is there third party manufacturers.
After all we can buy almost any component which is non-origional so why don't the computer builders start making them. We could then carry one as a spare in the boot. No diagnosis needed just plug the spare in.
Re: ECUs - Tom Shaw
I suspect that the high price of a lot of spares, which must give the seller a correspondingly high profit margin, is a sweetner from manufacturers to their dealers in order to keep them selling new cars rather than the more profitable used models.

Ditto cars which discourage home servicing.
Re: ECUs - Brian
My motorcycle dealer as much as admitted that to me.
I was complaining about the fact that certain parts, such as chains and sprockets, seem to built below the specification for the rest of the machine and therefore need replacing at, say, 10,000 miles intervals.
His comment was that if those items lasted as long as the rest of the bike then they would never have any servicing work to do.

With regards to ECUs etc., what sort of twisted logic, whether from manufacturers or governments, leads to a situation that in order to improve fuel efficiency by half a mile per gallon, thereby saving the owner about a fiver over the life of the car, you add fifty quid to the cost of a new car for a piece of unreliable equipment which is going to cost another hundred quid to replace at some time during the vehicle's life.

Truly, the patients have taken over the running of the asylum.


Value my car