Thread: TD5, Topside switch failed pre injection diagnoses help needed

Hi Joel. I figure this will be moved to tech chat or D2.
Anyway, yours is the first Ive heard log this fault and then start running again.
Give Jose (TD5inside) a PM, alternatively Tombie for definitive answer on the solenoid.
I have an MSB ECU here, I've had it as a spare for my previous D2, but it doesn't suit the EU3 Defer.
I can send up if you need to trouble shoot yours.
PM me if you need.

I'm acting as a medium for Joel. This came through the ouija board last night after a long seance...

joel0407
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Engine fault sovled. Well I think so
Hey mate,

On the weekend I got stuck in some pretty deep water. Not bogged, engine stopped.

The ECU had code 28-7 and 30-7 both are 28-7, topside switch failed pre injection.

Searching there are several threads on AULRO about the code and most have had to replace the ECU but none were conclusive to the problem.

Mine, unlike many, cleared after we towed it for about 2km.

I have found an answer that seems reasonable though.

The code usually indicates 2 Capacitors have blown in the ECU. These can be replaced rather than buying an entire ECU.

Apparently they die after a few good dips in water, which is what happens to mine on occasions.

I have found these Capacitors store the charge to fire the injectors. Once they fall below a certain charge they no longer have the power to fire the injectors and the code is thrown and the engine stops.

Mine would idle but not run. I checked while still in the water and my ECU was bone dry but the harness was obviously quite wet. What happens its the water is not a dead short but it does create resistance across the harness. This resistance is enough the drain some but not all the power from the capacitors. Each firing of an injector also drains some power from the capacitors. The capacitors had enough energy to fire the injectors at 1000rpm but any higher and the loss for the water shorting the harness and injectors firing went below a level they could maintain and the code was thrown.

All I need to do is seal the harness better and I shouldn't have the problem again. And if I do it's just a matter of opening the ECU and replacing a couple of capacitors.

Happy Days.

PS. the capacitors are soldered.

+1^^^, it's about those two big alloy capacitors in the ECM, you can't miss them, if the part number on them is faded the one near the margin is PEH169PA410AQ the other close to the middle is PEH169KE433AQ, they were originally made by motorolla or phillips very hard to find... i found only some chinese versions but they worked, you can remove and test them with multimeter, with analog multimeter is nice cos if the capacitor is good you can see the needle gradually moving to the end of scale, use method 2 or 3 from this link How to Check a Capacitor with Digital Multi Meter (4 Methods) ... unless you have a proffesional multimeter with capacitance scale, first is 1000yF and the second 3300

I'd put my money on a shorted harness.

Have a read:
http://www.aulro.com/afvb/discovery-...ml#post1615896

Rgds
Matt