Kolbjorn S

I was out driving in the 993 with my brother this evening, doing about 100 km/h on the highway when all of a sudden the engine cut out. Luckily there was a turn-off which I managed to exit at. The engine would crank but not fire up. We suspected a relay fault, but silly enough I didn't have a spare . I called the local authorized P-car dealer (SATA), who despite being closed arrived shortly after (fortunately just a km away) with a recovery truck. But, the exit I was parked on made it impossible to get the car onto the truck.

Then I tried to start the car (this was ~ 45 min after it stopped), and in fact it started! So we drove off - just to get 3-400 m away before the engine cut off again.

But the Porsche guys did not give up, and managed to mobilize the Porsche parts-guy who arrived at 23:00 to locate a new DME relay (both the original faulty one as well as the new one had parts no 993 615 227 00). When replaced (car still road-side), car started immediately.

The tech guys then insisted we drove to the Porsche garage for a check, and they opened up the workshop and at 23:30 night performed full system check on - while my brother got a brief guided tour of the shop! Those guys are just amazing - a big thanks! The only error message was related to air mass / flow(?); apparently related to the shutdown from the faulty relay.

Moral of the story is: Get a spare relay and keep it in the glovebox!

mnmblu

That would have never happened in the U.S. that's for sure. Good advice.

jrgordonsenior

What does the DME relay do?

Dealer notes: In Boulder, Colo a few months ago, the radio/cd/navigation system took a dump on me in my ML55. It was a Friday and I had just arrived in Boulder for a wedding. I didn't want to drive back to Calif. without tunes or nav so I took it to the local MBZ dealer in Boulder. He had to overnight in the complete unit, and then had it installed that Saturday even though the service department was closed. He then had the car delivered to me at the wedding reception on Saturday night! All at no cost. Of course I sent him some great Calif. wines and a bridesmaid.....
JRG

graham_mitchell

I believe it controls the fuel pump

993RS

Here is what it looks like:

DME Relay

slapshot

Graham is correct. It is the fuel pump relay. $27.00 at Pelican Parts with shipping. Definitely worth having an extra in the glove box.

mnmblu

Gonna order one tomorrow. Thanks Phil, and welcome back.

User 4221

When I had my 928 relays were always a concern because of the car's age and, not to mention, the car has about 18 relays on it panel.

Knowing this, I made a jumper wire that was a short piece of wire with spade connectors crimped on the ends. I kept it in the fuse box.

In the case of the fuel pump, you could use the jumper to manually connect the fuel pump power conenctions on the relay panel. This should correspond to connections 30 and 87 on the relay. The pump would immediately begin to run but would get you home.

HTH,
Scott

993RS

I spoke to my mechanic, who recommends that the DME relay be replaced as part of preventive maintenance every 40,000 miles.

Ms Kita

My car failed me and it was the DME relay. The car was towed, with a the customary cash pay outs. When I described my symptoms...no one on this board had a clue. The incident cost me a couple of hundred dollar for a part that was less than $25.00.

kdurg

In addition to the fuel pump, the DME Relay powers the 4 heater coils to the O2 sensors.

Most 993's came with a 944 DME part number(944.615.227.00). What's peculiar is the 944 DME was designed to power only the fuel pump of the 944 series and not the additional load of the heater coils in the 993. Thus, the number of failures we hear of.

The updated 993 DME Relay part number, if not already replaced, is 993.615.227.00

993RS

I have a copy of the DME link I posted in my car, along with a spare DME relay. Recommend Rennlisters to do the same.

Lorenfb

As the name implies, this relay provides power to the DME control unit in addition
to the fuel pump. So, a bad relay not only affects the fuel delivery but the functioning
of the DME control unit causing a no-start or intermittent running condition, although
the fuel pump may operate.