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NOT...!! ABS activates when the controlling ECU predicts that wheel lockup is soon impending. Basically ABS activation would mean your brakes are doing their job. The tires may not have enough frictional coefficient with the roadbed surface to keep them rolling. Personally I have ALWAYS been of the opinion that in highly tractive conditions ABS is, can be, more of a detriment than an asset. Some year ago I always pulled my ABS pumpmotor fuse during the summer. The simple solution for all of us, all around, would be to disable ABS unless the stability control system indicates that stearing control or correction is needed.

Hmmm... Look closely at the area of the intake runner below the valve stem. See how CLEAN that area is..?? Seems to imply, for me, a valve seat leak in that area.

I would much more readily believe that picture is the result of an ordinary, "standard", intake valve stem seal failure. Anyway, just when did the Cayenne engine adopt DFI..??

"...more data to get the measure of things..." EXACTLY...!!

Sorry, I'm still not buying in. I have disassembled and cleaned not just a few EGR recirculation valve systems over the years, mostly Lexus', and I've never seen crud of that nature. Think of what the catalytic converter would look like if the exhaust gasses contained "deposits" of that type/volume. Oh, how many miles on that Cayenne...??

I don't think I can "buy" into this, seems more like a scare story to me. With DFI there is ONLY air on the intake side of the valve, if the picture was actually from a DFI engine then the valve seals would have had to fail, or the valve/seat is leaking pretty seriously. What is the source of the picture...??

Your other choice was to pop the cover off of the flasher relay and replace the nichrome current sensing link with a 0.5 ohm 5 watt resistor. 5 watts is not needed unless you have need to temporarily install an actual incandescent at some time in the future. The nichrome link is designed to drop >100 millivolts at 3.5 amps. The two LED bulbs will draw only 200-300 milliamps so the 0.5 ohm resistor should suffice. With 1 LED bulb "failed" you will then still get "fast flash" as an indicator.

Just finished a complete LED exterior update/retrofit for our 1988 Carrera SE. 1. Dual color 1157, HID/white parking/marker mode, amber turn signal mode, $25.00/pair, ebay seller para2386. 2. Red 1157, rear tail/stop, $30.00/pair, ebay seller peraccurate. 3. Red 1156, rear turn, $30.00/pair ebay seller peraccurate. 4. "HID"/White 1895, rear marker/parking, $14.00/pair, V-LEDs. 5. "HID"/White 1895 "Flank", front marker, $14.00/pair, V-LEDs.

That would work really well on AC... ;) D. It also works well to make the LED bulb non-polarity sensitive, as in the above case. Thanks for the update W. :) I thought that a rectifier bridge was used to change AC to DC by stripping off half of the wave... but I guess what you are saying does make sense even though I wish I knew where to shop for the right LEDs. I figured they were all made the same. When I spoke to superbrightleds about this problem they did not have a solution and did not know of the issue entirely. Maybe I bought cheap 1157 LEDs as I found mine on eBay... In either case if it is not too much trouble can you send a schematic for a full wave bridge rectifier that you describe. I am somewhat familiar with circuitry but I need a visual to understand it entirely. I would like to compare your schematic to the actual 1157 LED schematics for future reference. Thanks again, D. V-LEDs on ebay.

That would work really well on AC... ;) D. It also works well to make the LED bulb non-polarity sensitive, as in the above case.

Check for stuck brake caliper piston first, piston is now operating in a new "region". Caliper stuck on rotor will produce heat that you can feel after a drive. Did you bed the brake pads? Tie rod ends replaced with suspension? Jack up wheel and check for free play. You are right to suspect bearings, especially if they have not been replaced or repacked after 139k. You sure it is from front? Similar symptom from failing CV joint when turning and accelerating. You are describing, perfectly, the symptoms I experienced in my '78 Targa with the caliper piston stuck, just barely stuck so it really only made noise when turning.

"...replaced brakes..." Check for stuck brake caliper piston first, piston is now operating in a new "region".

Most LED bulbs have an internal fullwave bridge rectifier that negates this problem.

Located in the front area of the passenger side radiator cooling air intake. An open circuit would indicate -30F a sorted one (apparently) 135F. Unusual for the fully epoxy encapsulated thermistor, check wiring first.

There is good spark and the fuel pressure after the filter is from 25-35 psi while cranking, is it suppose to register with the key on or just when cranking? we are able to get it to somewhat run if we manually open the air inlet valve but it won't stay running if we let go of the valve. The fuel pump power circuit is a little complex. Without the engine started the fuel pump only works in the ignition starting position. Once the engine starts, engine vacuum results in intake airflow, there is a microswitch on the intake airflow fuel metering inlet plate. The microswitch is out of adjustment or you have a blown airbox and the intake airflow has other openings to get to the engine.

Swap in a complete turbo engine or jsut add the turbo to the existing engine..?? The turbo engine would already be detuned/derated, <8:1 CR, in order to accomodate, make use of, the turbo's FULL boost capability. The easiest way to detuned/derate the existing engine might be to add the thickness of 1 or 2 extra head gaskets.

May I ask why you would want to do that...? On my '88 the crossover networks are in the door pockets.

Partially deflated left front tire..??

Maybe a great read, I just finished, but totally, TOTALLY idiotic. The sole control of A/F mixture during engine idle or "cruise" is left to the upstream oxygen sensors, closed loop. During these periods, mixture STRICKLY controlled to stociometric, the MAF/IAT signal levels (now operating under known, controlled, intake airflow conditions) are "captured" for later use filling in a parametric mapping table to be used under/with higher engine load/loading conditions wherein the mixture MUST be enriched beyond the measurement capability, range, of the oxygen sensors. The MAF/IAT module/assembly is only able to measure the actual intake airflow volume/rate in a very small area of the intake airflow path, a snapshot, if you will. So the overall, total intake airflow volume must be calculated from that rather small sample. Add a CAI, Cold Air Intake, ANYTHING that impacts the calculation of intake airflow volume and the factory parameters used to facilitate the intake airflow volume from the small (area wise) sample might become USELESS. Like the clock fully stopped only being correct twice a day, your A/F mixture will only be "correct" for engine idle or cruise periods. Oh, since other than at WOT times the throttle plate constitutes the primary restriction then any intake airflow modifications that impact flow volume will have little or no adverse effect except at or near WOT. Just what yawl needed to hear, right..!!

At "those" speeds the windflow is your windshield "wiper" insofar as outside condensation is concerned.

"..Maybe it works well in Stuttgart..." No, while we didn't experience any windshield fogging during our tour of the Castles of Europe in the spring of '01 we did take notice of a directly related system operation anomaly. I did bring the effects to the attention of our factory rep when we returned the car for subsequent shipment to the US. Throughout our tour I had noticed that I often, too often, had to "dicker" with the climate control temperature setting in order to maintain the cabin at our comfort level. After returning to the US and inadvertently discovering the condensation problem I examined the operation of the '99 and '01 climate control system more closely. In doing so I came to the conclusion that what had been happening to us in Europe was that once the cooling airflow began to be distributed, "dispersed", via opening the windshield and footwell outlets the overall cooling effect declined accordingly. Also, glass is NOT a very good insulating material so the cool airflow to the windshield mostly served to cool the windshield itself and thereby also the great "beyond". That resulted, of course, in less cooling capability, overall, to the passenger cabin. So, once the cooling airflow was "dispersed", radiant heating from sunlight would become the more dominant comfort factor and I would then react by lowering the temperature setpoint. 70F vs 72F, soon TOO cool, rise it. These days when I use the cooling capability of our C4 I set the temperature control to MAX COOL and recirculate and then use the blower speed to "regulate" our comfort level. Often having to add dispersion of the too cool system outlet airflow via opening the footwell vents along with the dash vent. NEVER the defrost/defog/demist outlets, it would take an IDIOT to intentionally do that. I have learned, the HARD way, that the dehumidification capability, efficiency, of the A/C system is totally a "WILD CARD", more likely to be NON-FUNCTIONAL in my area of the country than otherwise, I NEVER allow the system to be used, activated, except for actual cooling or initial cool down.

"..other cars do not do this.." Except the ENTIRE Toyota/Lexus fleet using automatic climate control. Actually almost ANY vehicle, mostly US and asian origin, using NipponDenso, Denso US, automatic climate control designs. Most of these vehicles even have a warning/caution note in the owner manual about this potential. But unlike the idiots at Denso the european models at least take the correct action if the defrost/defog/demist mode is entered manually. INSTANT, massive levels of HOT airflow to the interior surface of the windshield.

Amazingly VW has provided a firmware fix for this problem on their version of the Cayenne while Porsche still pretends not a design flaw. I first reported this "flaw" in June of 2001. Subsequently I tried to get it addressed via the local dealer who tore up the service order after I explained what the "job" was to be. In my '01, and previous '99, once the cabin was cooled down to within a few degrees of setpoint the defrost/defog/demist airflow ducts would be opened. I suppose this was to reduce the discomfort of cooling airflow to the face and upper body once the cabin itself was comfortably cooled. My '01 C4 now has a toggle switch within the console glove box that I use to open the compressor clutch throughout the winter and times that cooling or cool down is not a requirement. Other than the switch modification my solution to exterior windshield condensation, inadvertent, even DANGEROUS(***), windshield condensation, has been to manually cycle the defrost/defog/demist airflow "on" then OFF. Apparently this action places just that function alone under manual control leaving all others in automatic, including the dash airflow outlet control and the footwell control. ***In late June of '01 we took US delivery of our C4 in Charleston NC at about noon. Hot and humid day, and as is typical to this area of the country sporadic late afternoon showers. Approaching Birmingham Alabama just after dusk, not quite full darkness, I did not at first realize why my night time distance vision was being slightly "eroded". Finally came to the realization that a fine, thin, film of condensation had formed, was continuing to form, on the outside of the windshield. A quick swipe of the wipers cleared up my forward vision INSTANTLY. The C4 has rain detecting wipers but my guess is that the onset of condensation was so slow, and the water "droplets" so tiny, that the rain sensor never triggered. Be careful out there..

If the reheat/remix blend door happens to be stuck in the full reheat position then you will get NOTHING but heated outlet airflow. "...servos moving continuously.." No, more probable that the reheat/remix blend door's servomotor is TRYING to move the door away from the full reheat/remix position. If you set the temperature control to max heating the blend door will need to be in the full reheat position and the servomotor sound should stop. Is the compressor cycling on and off...?

Yes, with all these continuing technological improvements at some point in time maybe they'l begin downsizing the engines. DFI, variable displacement engine oil pumps... Toyota is now using extended VVT-i to change the CR from 13:1 to 10:1 as the engine goes from low and moderate loading to heavy. Can a positive displacement continuously variable speed SC (no throttle plate) be far away..??