Fault Codes - Help!

[ZEDonist UK]

Hi Everyone.

Long time no see

Im finally getting my Z3 back on the road after 2 years. It was all going well….

I’m now getting fault code:

P0604 Internal control module random access memory (RAM) error

also

64 DME control unit self test

i clear the fault but it always comes back. The car will crank strongly but not run, most of the time. If I can get it to start it’s very rough at idle and various warning lights come on. A tickle of the throttle helps stabilise things a bit

I’ve installed a new battery. If I can get the car started then clear the fault codes with it running then I can drive no problem with no faults. If I turn the engine off I get the issues back.

what are people’s thoughts on this?

Thanks
Martin

 

[ZEDonist UK]

Ok.
So I’ve spent the day fiddling and achieved very little

I now have errors;

5E1 9 ABS-DSC CAN Data error from DME/DDE (DSC lamp on as long as error is present)

64 DME Control unit self test

P0604 Internal control module random access memory (RAM) error


I’ve taken the DME / fuel pump relay out and tested that. It’s ok.
The car has a new battery and good voltage

 

[ChrisD]

Ok.
So I’ve spent the day fiddling and achieved very little

I now have errors;

5E1 9 ABS-DSC CAN Data error from DME/DDE (DSC lamp on as long as error is present)

64 DME Control unit self test

P0604 Internal control module random access memory (RAM) error


I’ve taken the DME / fuel pump relay out and tested that. It’s ok.
The car has a new battery and good voltage

A RAM error DTC indicates a serious internal issue with the engine control module. I would not attempt to run the vehicle with that error code - the potential for expensive further damage to occur is high.
I believe you need a replacement ECM, sorry to have to inform.

 

[Althulas]

I would disconnect the battery and leave for 10 to 15 mins to allow any capacitors to discharge and then check your DME, unplug it and check the connections for any corrosion. You could take the DME casing off to inspect the circuit board for any obvious burn damage and that there has not been any water ingress.

Also check wiring connections to your abs pump and throttle body.

In the past I had a memory error code on my DME. I could not see any damage to my circuit board but used a heat gun to air it anyway and gave my connections a squirt of electrical contact cleaner and all was ok afterwards but it’s worth a try before looking for a replacement DME or sending it for an inspection.

 

[ChrisD]

I would disconnect the battery and leave for 10 to 15 mins to allow any capacitors to discharge and then check your DME, unplug it and check the connections for any corrosion. You could take the DME casing off to inspect the circuit board for any obvious burn damage and that there has not been any water ingress.

Also check wiring connections to your abs pump and throttle body.

In the past I had a memory error code on my DME. I could not see any damage to my circuit board but used a heat gun to air it anyway and gave my connections a squirt of electrical contact cleaner and all was ok afterwards but it’s worth a try before looking for a replacement DME or sending it for an inspection.

In general, opening up an ECM outside of an anti-static clean room is a bad idea. There are no user serviceable parts inside and no possibility to run diagnostic tests that would confirm the unit has a clean bill of health.
At this point, however, the ECM is showing all signs that it has failed so why not? Have at it, there’s not much more to lose and you may get lucky.

 

[ZEDonist UK]

Thanks guys

I’ve had the DME out and opened up the casing. I’m aware of static discharge so all was handled extremely carefully.
There’s no clear signs of damage, water ingress or component burn out.

I’ve given all the DME connections a good spray with contact cleaner and allowed to dry before reconnecting and energising

The fuel pump relay (often referred to as the DME relay) which is located next to the DME (light green one) is healthy. I’ve swapped it around just in case, it didn’t seem like a likely cause

Cam shaft sensor was swapped as this was often T-Tony’s point of concern

Crankshaft sensor shows a steady 270 rpm when cranked

I’ve checked and cleaned the ground cable located on the drivers side suspension strut tower which made no difference

I think what I’ll do next is run a ground directly from the battery to the engine bay.
I’ll also get my hands on a proper battery tester which tests battery health when passive and under load.

What I can’t help but think is that there is a common issue which relates to the ABS and DME module.
They are both located in the same section of the engine and they are both showing a fault.

 

[ChrisD]

Thanks guys

I’ve had the DME out and opened up the casing. I’m aware of static discharge so all was handled extremely carefully.
There’s no clear signs of damage, water ingress or component burn out.

I’ve given all the DME connections a good spray with contact cleaner and allowed to dry before reconnecting and energising

The fuel pump relay (often referred to as the DME relay) which is located next to the DME (light green one) is healthy. I’ve swapped it around just in case, it didn’t seem like a likely cause

Cam shaft sensor was swapped as this was often T-Tony’s point of concern

Crankshaft sensor shows a steady 270 rpm when cranked

I’ve checked and cleaned the ground cable located on the drivers side suspension strut tower which made no difference

I think what I’ll do next is run a ground directly from the battery to the engine bay.
I’ll also get my hands on a proper battery tester which tests battery health when passive and under load.

What I can’t help but think is that there is a common issue which relates to the ABS and DME module.
They are both located in the same section of the engine and they are both showing a fault.

There is a communication link between the ECM and brake controller that is used for torque intervention during traction events. A problem with the ECM (confirmed by the P0604 DTC) is very likely to trigger a communications DTC within the ABS unit.
Carry on confirming all the connections are good but it really looks like your ECM is faulty.

 

[ZEDonist UK]

The link between the DME and ABS module is good knowledge I didn’t have.

My feeling is that the module is faulty too if I’m honest. It’s a very clean car and I don’t believe it would be an earth strap fault. It’s just something I can test.

Presumably if I get a replacement identical DME and EWS module I’ll be able to install both to the car and drive to prove the car is fixed?
I can then take the replacement units back out and send the original module and the donor module to a specialist who will be able to clone my original DME onto the donor one to maintain my mileage etc?

it’ll be nice to test the vehicle before spending the extra on a cloning service

 

[Pingu]

I think you need more than mileage cloned. I think the engine ECU is matched to the car.

Whenever I get a computer glitch, I disconnect the earth and then use a jump lead to connect the positive battery pole to the chassis. Apparently, this discharges all the ECU capacitors.

I'm not sure if it help, but it's never done any harm.



I'd get hold of someone with INPA, and see what it detects.