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I recently purchased a very nice 997.1, 6spd, with a clean PPI and literally the day the car was to ship from the seller to me it developed a hard start issue and the typical Check Engine Light. Luckily the car was at a Porsche Dealer but there was literally no time to order a sensor and service the car before my trucker arrived. In addition, the dealers going rate puts this service at about $800 all in. No Thanks!
Symptoms - Hard start, or no start when cranking for several seconds. Reason - When the code was pulled, it pointed to the Coolant Temp Sensor and the computer was telling the car its coolant temp was -40deg, thus effecting fueling and timing.
The sensor in question is Part# - 997 606 420 00
I sourced the part at my local Porsche Dealer for $28
Like anything on the 911's it can be a real chore getting to the parts in need of repair.
The sensor is located behind the altenator in a water neck under a small plastic engine harness tray.
In order to get to it the procedure is as follows: DO NOT DROP ANYTHING INTO THE ENGINE BAY, TAKE YOUR TIME!!!
***Disconnect your Negative battery terminal***
Remove Air Box Cover.
Remove Air Filter.
Loosen Y pipe coupler clamps Left, Right and Center top.
Remove sensor clip in Y pipe.
Using a small flat screwdriver or pry tool, remove each rubber boot on the Y pipe.
Remove Y pipe, there are two posts that are snapped into the intake box.
Disconnect MAF harness plus on each side of the intake box.
Disconnect the small corregated plastic hose on the left of of intake box.
Gently pull up on the box and remove it from the engine bay.
Now with the intake components out of the way you will need to release tension on the serpentine belt. This is easily done with a 15mm socket and a long ratchet or breaker bar. I took the belt off the alternator and set it on top of the belts track and it remained snug with the tensioner released and no fear of coming off other components!!!
The alternator is held in place with two E-Torx bolts, once facing you on the right side and one reverse mounted on the left side. You'll need a short E-Torx socket to fit the reverse mounted bolt.
Remove the Bracket above the alternator holding the Oil Filter Cap to gain more clearance. Two smaller E-Torx screws and two 6mm socket head allen bolts. The lower allen only needs to be loose, do not remove it.
Remove both bolts holding the alternator tabs.
Pry the alternator out of its cradle gently and then disconnect its harness clip and power wires. Note the position of the larger gauge wire for when you put it back, it must sit in the lower angle tray.
With the alternator out of the way you will see the sensor hiding behind a plastic harness raceway.
Here's the tricky part, Thanks to Porsche!
The sensor is 22mm and sits in the water neck behind a small threaded boss and under the intake plenum with limited overhead space...
You'll need a socket that isn't a deep socket and one that's tall enough to clear the plastic portion of the sensor. Wrenches aren't of much help due to the threaded boss in the way.
Once the sensor is out, you can install the new one, top off some coolant if needed (not much will come out) and replace all the parts in the reverse order.
My car started flawlessly, all codes cleared themselves and it's back to driving normal.
I hope this helps anyone with the same issue. I searched the forums and came up empty.
CHEERS! Eric
Last edited by FirstStateCamber; 03-01-2018 at 09:40 AM.
Hello, preparing to change my temp sensor on my '07 911/997.1 Turbo. Just wanting to confirm that this procedure is for a turbo. Do you have any schematics for removing the airbox and y-pipe?
03-01-2018, 09:16 AM
