991.1 Turbo S "4-wheel drive limited" warning on dash
#16
The following users liked this post:
CodyzWorld (10-01-2024)
#20
AWD Error
I recently got the same error on my 14 TTS. I'm trying to figure out the issue but my diagnostics does not give me a clear fault. I checked the pressure sensor and it has 12 v going to it and output is 0.00 Volts. So I'm not sure if that is because it has no pressure or the sensor has failed. These cars use a hydraulic pump to clamp the friction plates to engage the front drive, so at idle the pump does not appear to be running (no voltage to pump). The pressure sensor monitors the hydraulic pump pressure. So is the pump bad or the sensor? I'm leaning towards the sensor because the impedance across the sensor indicates an open circuit. Of course, the $30 value sensor costs $330 with a discount so I want to make sure before I buy. Also pretty sure the oil pump motor still works because the dash shows the front drive being engages as normal. Interestingly, the Cerrara 4s does not include the pressure sensor, so the system can work fine without it.
Any thoughts?
Any thoughts?
#21
It ended up being the pressure sensor. Although difficult to get to and a bit tricky to remove, there is no need to lower the drive or disconnect any coolant lines. To remove:
1) Jack up car an put in 4 jack stands.
2) Remove the front under panel and remove the screws for the middle panel but it can just stay on place loose.
3) Remove the V shaped brace that blocks the back of the front drive. It's six large screws and two smaller ones that attach to the water pipes.
4) Pull the electrical connections for the lower temp sensor and the upper pressure sensor with long needle nose pliers.
5) Using a deep 24 mm socket ( the Harbor Freight 24 mm 1/2 drive impact socket works perfect) with a 1/2" to 3/8" reducer to slip over sensor.
6) Slip a 3/8 ratchet in place to engage in the reducer and loosen the sensor (watch that you do not pinch the wires). Remove with your fingers.
7) Very little fluid escapes so no need to change fluid unless you want to.
8) Installation is reverse of above.
The fact that the dealer charges $2-3k for this is insane. It took me about an hour and a half. The sensor is $360 discount.
1) Jack up car an put in 4 jack stands.
2) Remove the front under panel and remove the screws for the middle panel but it can just stay on place loose.
3) Remove the V shaped brace that blocks the back of the front drive. It's six large screws and two smaller ones that attach to the water pipes.
4) Pull the electrical connections for the lower temp sensor and the upper pressure sensor with long needle nose pliers.
5) Using a deep 24 mm socket ( the Harbor Freight 24 mm 1/2 drive impact socket works perfect) with a 1/2" to 3/8" reducer to slip over sensor.
6) Slip a 3/8 ratchet in place to engage in the reducer and loosen the sensor (watch that you do not pinch the wires). Remove with your fingers.
7) Very little fluid escapes so no need to change fluid unless you want to.
8) Installation is reverse of above.
The fact that the dealer charges $2-3k for this is insane. It took me about an hour and a half. The sensor is $360 discount.
Last edited by pjscrs; 04-23-2020 at 09:57 AM.
The following 2 users liked this post by pjscrs:
Agentorange (04-23-2020),
Jean (04-23-2020)
#24
my '14 Turbo S flipped this warning at me a couple weeks ago. took it in Thur. It is the pressure sensor located up in the front, requires dropping the awd system, estimate is $3600 for that repair. Unfortunately the tech ran a scan and found a whole list of things that were a year or 2 overdue. I asked him why those items hadn't been caught during the last couple annual services. said depends on the tech, and if the owner says, just an oil change, that might be all they do. i usually ask them to do any req'd service as well. things were serpentine belt, 2 pollen filters into the cabin, pdk reservoir, some other filter that's built into the drainpan as both of those have built in filters and have to be replaced every 4 yrs. total for all this came to $9600. the 'good' news is at 12 yr maintenance, a lot of the stuff will have already been done to soften the blow then. drag, but cost of ownership.