Hi, was hoping that somebody was able to help with a problem my cars developed. The EPC light illuminated on my dash, I was able to to read the faults and found it to be the dreaded P0601 "internal check sum error", I attempted to clear but it returned almost straight away on start-up. Although the light remained on there where no running problems what so ever with the car.

I booked it into my local main dealer (Carrs, Exeter) and hoped a simple ECU flash/update would clear the problem. They took the car in for a diagnostic test and update (min 2 hours labour), I received a phone call to say they didn't want to carry out the update/flash as it may render the car totally inoperative and that a ECU replacement is what they recommended at a cost of £1400+VAT & fitting.

I declined this offer and have decided to try and source a second hand replacement on eBay/scrap yard. I was wondering what to look out for when buying one second hand, what part number would fit my vehicle? and would it require programming on fitment? 

I was hoping that somebody may be able to help me with this issue, thank you.

There are many places like Shark where they can refurb and repair the unit. I would'nt want to take one from a scrappy.

Hi, thanks for the fast reply, just sent Shark a message asking for info. The problem is I use the car daily for work and cant really be without it for a long period, living down in Exeter I'd probably have to remove and ship the ECU to Shark.I wondered if buying a second ECU might be a option (£150 on eBay), but wondered what to look out for. Then I can send my inoperative one away to be overhauled. Thank you again.

I've been in touch with several ECU specialist, they have offered to flash the ECU but did say its not a sure fix, but a good chance. Unfortunately the only way of testing it is to actually flash the ECU, however if the software fails to load the car will be completely inoperative. It cost £60 so its a risk I'm going to take as its a lot cheaper than the £1400+VAT & labour.

 

Has anybody else ever had this problem and cleared it with a simple re-flash?

I have had the same problem but just left the lights on the dash, its been about 4 years now.

 

Would be interested to know how you get on as I might look at getting it fixed if poss.

We can fix this with a reflash.

Tried a reflash of the stock software but no joy, today I replaced the ECU with a serviceable unit loaded with my car data, fault still returns!!

 

It looks as if its a issue external of the ECU, when hooked up with a VAGCOMM at the local independent garage it showed the fault is only generated on start up. The car starts absolutely fine itself but you can see the voltage to the ECU drops to 7V then returns to 12.5V, is this normal? If not where's the best place to look? the ECU connectors look spotless.

 

Hope somebody can help

 you can see the voltage to the ECU drops to 7V then returns to 12.5V, is this normal?

No,this is not normal. These reading are actual from ECU connector tested with multimeter or live data on screen from diagnostic tool?

Edited 23 January, 201511 yr by IngusSeflers

Thanks for the reply, the reading was through a diagnostic tool.

Before you make any decision about ECU replacement, you need to be sure about 'real world'. Check that pin with multimeter on connector side with connected to the ECU and running engine. Then with disconnected from ECU. See results then...

Sorry about my English :p  

Edited 23 January, 201511 yr by IngusSeflers

Thank you, where would I get the wiring diagrams for the ECU connections? Thanks for the advice.

 where would I get the wiring diagrams for the ECU connections?

You need ELSAWIN,AUTODATA or somebody with that software

Edited 23 January, 201511 yr by IngusSeflers

Tried a reflash of the stock software but no joy, today I replaced the ECU with a serviceable unit loaded with my car data, fault still returns!!

If you reflash it with the same stock software, it won't help! 

 

P0601 Internal Checksum Error can't be caused by something external to the ECU, the clue is in the fault description.

 

What method did you use to load the serviceable unit with your car's data?

Even a voltage drop to 7V during start? Surely that could possibly interrupt a computing process within the ECU? The fault is generated with engine at 0 RPM. Seems after a full ECU swap for a known serviceable item that it must be something external. I think the ECU might be a red herring in this strange case!

It was the ECU in the end, the second unit that was fitted had the same fault, lucky it came with a warranty! New unit fitted fault cleared! Can't fault this guy for his help and service, http://www.the-ecu-doctor.co.uk saved me over £1500 on what Skoda main dealer wanted to charge for a new ECU!