seither

My 2006 4.5L cayenne S large fan started to run continuously after I came back from a trip and my car was sitting in a long term parking lot for 10 days in a record cold spell. The car might have been jumped by the lot crew. I read the above post and here is what I have now.

I haven't tried to scan the car yet as I don't have a scanner so I disconnected the fan plug and jumped the power wires to give it power to see if it ran without the PWM pulse train. It didn't run so I assume no hard fault in the fan drivers yet (I'll Oscope the pwm signal to the fan today).

The analog temp gage is working ok and the engine comes up to temp fine, right in the middle of the range as usual so I'm thinking the sensor is ok. The one on the back side of the intake manifold.

I'm thinking something put the fan logic into safe mode, maybe the battery or it being jumped. Is that possible? I'm going to have it scanned at autozone today and I'll report the results if they can do it.

My plan is to reset any error if found and see if that fixes it. I'll have to find someone who can reset it on the cheap as autozone won't reset it. Is there any thing I'm not considering in my debug steps? What solenoid is 42empress talking about? Has anyone seen a fan go into a safe or "limp home" mode before?

Thanks, when I fix it I will update the thread.

seither

Ok I fixed it. I'm not sure of the exact cause though. About three days after the fan started misbehaving. I smelled coolant while driving down a hill and a few drops on the garage floor. I added coolant and still fan was running continuously. I figured the coolant pipes just went so I replaced the pipes and the temp sensor on the back of the engine even though it read within range from another posts readings. After it was all put together I started it up and the fan ran fine. It is a mystery to me how the fan knew that the coolant pipes were leaking. The temp was good and the level was full but somehow when I fixed the pipes it started behaving normaly. One tip to removing the pipes that may be handy was to use a jig saw blade with the teeth ground down to extract the broken off pieces of the plastic tubes. Hold it with a vise grip and heat to red hot and you can burn through the plastic and double o rings to loosten the pipe end for removal if it is stuck.

matt_o_70

looking for any experienced feedback on same topic.. My 04 S - I have witnessed the Fan come on randomly when the car was cold, parked and key off. Record cold temps during the winter pulled the big fuse for a bit.

Then again recently when car had been sitting in driveway and not driven..so now that weather is nice I'd like to fix this issue.

Is there a thermo fan switch?

If controller is built into fan assembly and possibly flakey - Is there any testing possible or typical codes?

In looking at parts diagrams Left fan seems to show electronics onboard. where as Right fan may be fan only. If you replaced a fan did this resolve the issue for you?

gbratk

I had the same problem... It was bad connection inside plastic connector on fan side.
I cut connector to get to the wires put new pieces of wires solder it, and then glue connector back. The problem was on two small wires.
That was more than year ago, and no problem since then.

seither

One note I forgot to mention regarding my issue with the fan. After pulling off the parts to fix the pipes and inspecting the temp sensor I noticed it was flooded with coolant probably misleading the sensor and turning on the fan. I did not replace the sensor and after cleaning the coolant the fan stopped staying on. Fan no longer stays on.