Hi
Any help here would be much appreciated. 04 xfire in Limp mode. After been around 3 garages to be repaired including main dealer in Northern Ireland. I sent ECU to Autotek in Bournemouth who tell me throttle communication burnt out, info on brain needs copied over or something like this. I have emailed them for details in writing but no communication as yet. Looking £470 to repair unfortunately I have since seen their reviews on Google. I am not really willing to part with this cash going by reputation (I wish I had of checked beforehand). I was wondering if buying a used ECU would be possible or would I need key and ignition etc. I really don't know what to do next. Car has been like this for 5-6 months.

 

Limp mode is used in context with the automatic transmission.
In limp mode the car uses only 2nd gear in the auto box and is not a condition seen on a manual transmission.
On the manual tranny cars and the auto tranny cars poor performance is caused by one of many possible faults. Get any fault codes read using an OBDII scanner.
I doubt that it is caused by the ECU if it is a true Limp Mode condition.
You should have come here first, get the ECU back and look for the real problem.

 

Thanks for your quick response 180. Regrettably your right I should have come on here first. The background is the BAS/ESP light started to come on intermittently, car is manual transmission. Then one day it stayed on and car went into a what I described as Limp mode(car low revs, moved at a crawl. Before I got someone to look at it the battery went completely dead, when charged the car cranked on IGNITION ON which it still does strangely. I changed the battery as it was old. The Car went to former Chrysler dealer where it was bought. They told me there was a ball of fault codes coming up and they had to decipher what the real ones where. They changed ignition switch, pulse module, sent brain away to test circuits it came back fine. They only checked the circuit didn't plug it into computer. 2 months later got it back, not fixed. Had it with a Mercedes technician, he 'said' he tried changing throttle body, no difference although I reckon he didn't spend too much time on it. Took to NITEC Coleraine a Mercedes 'specialist'. They told me there was no CAN communication to the throttle body and advised sending it to BBA-Reman. They would not work on this ECU and AC tronics only work with trade. This left me googling and I spoke to AUTOTEK. Guy sounded decent and informative so desperate at this stage I sent it away only to see dreadful reviews later. Ahhhhhhhh sigh! I will probably just pay them the £84 diagnostic charge but I'll still be back to square one.

 

Hmm.. bad throttle pedal comes to mind here..

 

Hi Mrmiata
Throttle body, pedal, air flow Meter has all been tried.
AUTOTEK has advised the 'throttle body drive circuit has been overloaded' and I need a new PCB (CIRCUIT BOARD). The info from the faulty PCB needs to be copied over to the new PCB and everything should be hunky dory! All sounds good but at £470 with no comeback with this company its a gamble.
Any advice?😞

 

Read the fault codes, anything else is a guess.

 

Hi

Sorry to hear that your car has been out of action for so long. I'm sure you've been given the run around, some repairers will tell you anything (when they really don't know themselves). As others have mentioned here the obvious things that came to mind were a bad or reversed connection on the throttle pedal (but that won't generate a check engine light) or something going on between the ECU and the throttle body, ie. bad connection or wiring short (that might generate an error code). If you find a wiring short your ECU might still be OK. Knowing the actual error codes would really help a lot, but if a repairer has read them before then they've probably also erased them.

You must make sure that you get your original ECU back from the repairer as it contains all the information that matches up to the immobilizer (skreem module) in your car. It's much easier to make a new ECU if you've got the original ECU to copy.

I wouldn't normally expect an ECU to fail, but it could happen. My main concern would be that whatever caused the ECU to fail (eg. a short in the engine wiring harness) might still be present and cause the same failure in any replacement ECU. It would be very odd for the ECU fail all by itself. So check this out before you plug another one in.

However, to answer your original question, yes your original ECU can be easily duplicated using a used ECU from the wreckers. You wont need a new ignition, keys or skreem module. The best ECU to use would be one from another manual transmission Crossfire.

If you have a reputable electronic repair shop near you, take the ECU's to them and show them these instructions.

1. Unscrew the cover from the ECU.



2. Lift off the lid from the bottom casing.



Note. the rear edges of the circuit board are glued to the lid with mastic and we need to get at the rear of the circuit board.

3. Run a Stanley knife between the circuit board and the lid to separate them.



4. The 5P08C Eprom circled in Red contains all the vehicle ID data and coding. Pin 1 of the Eprom is marked in yellow. We want to copy this chip!



5. Connect an Eprom Reader/Programer to the 5P08C on the Original ECU and read the binary file from it (and save it on a USB for future use).



6. Dissemble the donor ECU as described above, connect the Eprom Reader/Programer to it and write your original binary file to it (the one you just copied from your original ECU).

7. Reassemble the ECU (you don't need to apply new mastic), fit it to your car and start your engine!

If the repairer doesn't have a suitable in-circuit programmer then they could carefully de-solder your original Eprom and fit it to your donor ECU.

I hope this works for you out and you get to drive your car again soon. If you don't have the original ECU, then you'll need to buy a new one (or virginise a used one) and marry it to your vehicle using Mercedes STAR DAS (Xentry) software.

If anyone else ever wants any advice regarding Crossfire ECU coding or modification then please PM me and I'd be happy to help out.

Pic 1: Crossfire ECU

Pic 2: ECU with Cover Removed

Pic 3: ECU Circuit Board Separated from Top Cover

Pic 4: 5P08C Eprom on Bosch ME28 ECU

Pic 5: 5P08C Eprom hooked up to Reader/Programmer

 

^^^^^ AWESOME!!! Just AWESOME !!!!
This will indeed save a lot of people a lot of hassle.

STICKEY !!!

( BTW: where did that extra .2 litres come from in your engine ? )

 

Thank ya, thank ya, it seems easy and straightforward.

 

Hi ala_xfire

The extra 2.2 litres comes from a Mercedes ML55 engine I used for my V8 conversion. It's the 5.4L (332CI) normally aspirated version of the M113 AMG engine. I converted my Crossfire about a year ago and had to learn how to modify and code these ECUs. Everything works like it left the factory, it just has two extra cylinders.

 

Hi
Thanks for putting that together. Truly comprehensive and my appreciation cannot be put into words. You have give me hope I might actually get my car running again.
I will start looking for an ECU from wreckers. More than likely it will have to come from the mainland.
Your suggestion regarding the engine wiring harness, can your local mechanic check this out or is it another search for a 'specialist'? Or do you think I should just change the ECU hope for best?
Many many Thanks😃

 

Hi whiteviera

You could plug the replacement ECU straight in, but if you're not sure what caused the original unit to fail, then I'd check the wiring between the ECU and throttle body.

The wiring between the ECU and the throttle body is shown in the Crossfire Manual in section 8W-33 "Vehicle Speed Control". I think there's a copy of it on this site. There's six wires that run from pins 3,6,20,21,22 &19 on ECU plug 3 to the throttle body. If you're not sure how to check it yourself then print out that page from the manual and get an auto electrician to check it for you. It shouldn't take long to check.

 

Hi
Just got my car back on the road. Very grateful and appreciative for your help. What a time I had with it!
With it being laying about not really turned a wheel since its last service, I got a new battery and ordered so oil and filtering, anything else you would change? 69k on the clock.

 

What did you do to rectify your problem exactly?

 

Hi
I ordered a new ECU from Ebay US £108, then got data transfered to it from original £120 by Torquetronix, Antrim. Then NITEC, Coleraine the garage checked the wiring to throttle and inserted it, £120 to them and she came alive. Unfortunately the main Chrysler garage Todd's in L'derry took £236 off me before all this and never repaired it, they sent the ECU away for testing and told me it was fine.
Your instructions were fantastic. I'm out quite a few quid but at least she's running.

 

The post by CL770 is brilliant and I have added it to the Index of Crossfire problems, repairs and How To's ..... in a PDF form.

 

AMEN to that !
Scanning through eBay, looks like you might be able to score one of those eprom programmers somewhere in the $70 range .

 

Hi ala_xfire

Be careful with those cheap ebay units. A lot of programmers won't read the 5PO8C eprom, you should confirm this before you buy one. Some sellers say that their programmer works but I've found some only read half of the memory contents. If you only read half the contents and save it as your safe file or try and transfer it to another unit, you'll be in all sorts of trouble. The other thing that's very useful is to be able to vary the reading and programming voltages. When your trying to read and program with a device still in circuit it's important to keep the voltage as low as possible, otherwise other components on the board might start up and interfere with what your doing (eg. the microprocessor might start up). I use a programmer that's made in the USA (from Andromeda Research Labs), it's more versatile and costs a little bit more, but it does the job well.

 

I think just R&R as was suggested would be the easiest George. I can get to it, but, boy is collecting an reinstalling that info , way out of my league.
Good side job for somebody, any Volunteers? (I'm from 10ec but I can't hep).....

 

Good advise CL770, I don't know much about this and appreciate your expertise.