986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Momentary Hesitation @ 4000 rpm & TC issue. Is it the DME or ???

jvfante · 06-21-2016, 08:16 AM

Re: 986 1998 2.5L 5sp MT 139k 5.2.2 DME.

Engine cutout issue: When I accelerate aggressively the engine cuts out momentarily at around 4000 rpm. The CEL flashes on and off once but leaves no codes. This happens maybe 25% of the time, other times, the car runs very well without a hiccup.

TC issue: Coincidentally, after starting up, and at idle, the TC light and switch work normally, but as the car gets up to speed, e.g. 30mph, the TC light comes on and the button won't cancel it. The SB P-Dealer said the wheel speed sensors checked out okay (see below)

Since I got the car in March in need of several repairs, I have replaced the Bank 2 Solenoid, ramp and timing chain, all spark plugs (Bosch) Beru coils, Bosch MAF sensor, cleaned the Throttle body, new starter, battery, oil cap, fuel cap & fuel filter. Compression in cylinders is 165-180 psi. Fuel pressure is 48-55 psi at the rail.

I took it to the SB Porsche dealer for diagnosis of these two issues. Without another 4 hours of diagnosis, they were not able to nail the problems down, but gave me the following report.

"Scanned car found codes 5284 and 5285 in TC and fault 108 in DME. TC codes are for no comm with DME, wires from DME to TC tested okay. Disconnected TC and found car ran the same. When car cuts out CEL lights but no codes. This is indication of DME losing comm or power. Need further testing to determine cause."

I'm thinking my next step is to send the DME to be tested.

Any suggestions on other tests or how to proceed greatly appreciated.

06-21-2016, 08:16 AM	#1
jvfante Santa Barbara, CA Join Date: Mar 2016 Posts: 38	Momentary Hesitation @ 4000 rpm & TC issue. Is it the DME or ??? Re: 986 1998 2.5L 5sp MT 139k 5.2.2 DME. Engine cutout issue: When I accelerate aggressively the engine cuts out momentarily at around 4000 rpm. The CEL flashes on and off once but leaves no codes. This happens maybe 25% of the time, other times, the car runs very well without a hiccup. TC issue: Coincidentally, after starting up, and at idle, the TC light and switch work normally, but as the car gets up to speed, e.g. 30mph, the TC light comes on and the button won't cancel it. The SB P-Dealer said the wheel speed sensors checked out okay (see below) Since I got the car in March in need of several repairs, I have replaced the Bank 2 Solenoid, ramp and timing chain, all spark plugs (Bosch) Beru coils, Bosch MAF sensor, cleaned the Throttle body, new starter, battery, oil cap, fuel cap & fuel filter. Compression in cylinders is 165-180 psi. Fuel pressure is 48-55 psi at the rail. I took it to the SB Porsche dealer for diagnosis of these two issues. Without another 4 hours of diagnosis, they were not able to nail the problems down, but gave me the following report. "Scanned car found codes 5284 and 5285 in TC and fault 108 in DME. TC codes are for no comm with DME, wires from DME to TC tested okay. Disconnected TC and found car ran the same. When car cuts out CEL lights but no codes. This is indication of DME losing comm or power. Need further testing to determine cause." I'm thinking my next step is to send the DME to be tested. Any suggestions on other tests or how to proceed greatly appreciated.