HIGH GEARBOX TEMPERATURE MESSAGE

DJAG

MEMBER
2000 JAGUAR XJ8
V8
FWD
119,000 MILES

I have a 2000 XJ8L with 119,000 miles on it and prior to me replacing the throttle body I was receiving the high gearbox temperature, failsafe mode and then the after awhile the limp mode message would eventually come up and the car would not operate properly. I would turn off the car wait for awhile(maybe and hour or so) and then it would allow me to drive it a few blocks and the same thing would happen. As previously stated I just had the Throttle body replaced and the oil changed and filters changed on 3/10/11, but yesterday I got the high gearbox temperature message AGAIN! What could cause this? Car just off warranty Sept 2010 for my Dad kept renewing warranty until he passed. Can you help me with this?

10 Replies

MERLIN2021

MECHANIC
17,250 POSTS

First get the codes scanned autozone does it free, there are a few codes that cause limp in mode and once you post the code I can help.

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Thursday, March 17th, 2011 AT 6:19 PM

DJAG

MEMBER
6 POSTS

Prior to me getting the Throttle body replaced I was receiving the P0121 code, but I will make a trip to Autozone and see what comes up. Thanks

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Friday, March 18th, 2011 AT 7:33 PM

DJAG

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6 POSTS

I can do it if you tell me how. Upon further research and reading I was looking the transmission control module or something of a temperature sensor that may or may not come with a harness of some sort?

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Friday, March 18th, 2011 AT 8:12 PM

MERLIN2021

MECHANIC
17,250 POSTS

There are 2 important temp sensors in this problem one is the transmission fluid temp sensor and the other is the engine coolant temp sensor. Your problem sounds like code P0712 trans fluid temp high, and can be caused by either a bad sensor or a gounded wire in the sensor circuit. It can also tie into the ECT(engine coolant temp sensor. Testing is done at the TCM(transmission control module located at the right rear of the engine cmpatment, look for the Blue/Yel stripe and Black/Green stripe wires Use an OHM meter set on 2K and your readings should be as in the resistance table show in pictures below, Note that the ECT has the same color wires, so test the sensor there by removing the plug and checking across the sensor. The ECT is located on top rear of engine in the top hose.

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Friday, March 18th, 2011 AT 8:24 PM

MERLIN2021

MECHANIC
17,250 POSTS

And the ect spec below, IAT(intake air temp should also be tested with the ect on a cold engine, readings should be within spec. If you have a scanner that can read sensor data, read the coolant and air temp degrees cold, they should be within 10 degrees of each other.

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