00 Explorer lock-up falls out
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Cross-Country
Joined: Mar 2008
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00 Explorer lock-up falls out
2000 Explorer 4.0 dohc avd. 150k miles. The torque converter lock-up function has started to drop out. It can happen after some miles and will light a warning light in the dash that the manual states as "contact tech" or something like that. Everything gets back to normal with just a "blip" to "off-position for the ignition switch and might stay normal for all between 5 minutes to several hours. Seems to me it is an electrical issue. Dirt, sensors?
Runs and shifts fine other than this. Only thing I have noticed is that the temp gauge reads pretty low but I think this started earlier and I understand that the temp gauge has its own sensor.
Any ideas where to start looking?
Runs and shifts fine other than this. Only thing I have noticed is that the temp gauge reads pretty low but I think this started earlier and I understand that the temp gauge has its own sensor.
Any ideas where to start looking?
Posting Guru
Joined: Apr 2000
Posts: 1,746
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From: PNW
You might be onto something with the temperature gauge. How low is low? On the Fords that I have ('98 and earlier), the torque converter lockup is inhibited if the engine is cold. It doesn't tell me at what temperature the inhibit is removed, so I'm no help there.
Also, throttle position affects lockup. If your TPS has a bad spot right around where you cruise (which is where they tend to wear out), then it could be causing the torque converter to unlock. Can you get it to lock back up by pressing gently on the throttle to get the TPS off of its normal spot at cruise?
Don't run out and replace the TPS and temperature sensor (not to be confused with the sender). The above are just guesses on my part and further troubleshooting is required. You could have a wiring problem, too, in either of the sensor circuits or torque converter clutch circuit.
Also, throttle position affects lockup. If your TPS has a bad spot right around where you cruise (which is where they tend to wear out), then it could be causing the torque converter to unlock. Can you get it to lock back up by pressing gently on the throttle to get the TPS off of its normal spot at cruise?
Don't run out and replace the TPS and temperature sensor (not to be confused with the sender). The above are just guesses on my part and further troubleshooting is required. You could have a wiring problem, too, in either of the sensor circuits or torque converter clutch circuit.
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Cross-Country
Joined: Mar 2008
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Thanks Mikeman!
Temp gauge reads just a tad over "cold", like 1/3 of its way to "normal".
When lock-up disengages it lights the "contact tech" (or simular) light in the dash and no throttle action will make it go back to normal. Ignition switch has to be turned to "off" position to clear it. A split second in off-mode is enough and it always cures the problem for a while. Sometimes for a couple of miles - other times for the rest of the day. More ideas?
Can you explain the difference between sender and sensor?
Temp gauge reads just a tad over "cold", like 1/3 of its way to "normal".
When lock-up disengages it lights the "contact tech" (or simular) light in the dash and no throttle action will make it go back to normal. Ignition switch has to be turned to "off" position to clear it. A split second in off-mode is enough and it always cures the problem for a while. Sometimes for a couple of miles - other times for the rest of the day. More ideas?
Can you explain the difference between sender and sensor?
Transmission Rebuilder
Joined: Jul 2008
Posts: 1,570
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From: North Georgia
There is a trouble code stored in the computer for the transmission, you should take it somewhere and have these code retrieved. Once you know what the vehicle is seeing as a problem will you know where to look.
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Cross-Country
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Pulled one code: P0741 - "Torque converter clutch circuit performance/stuck off".
That could mean lots of things, but remember all it takes to turn off the light and get the converter to lock up again is a quick turn of the key to "off" position. Even done so fast that the engine doesn't stop is enough to get it back to normal.
Any ideas? Lockup solenoid?
That could mean lots of things, but remember all it takes to turn off the light and get the converter to lock up again is a quick turn of the key to "off" position. Even done so fast that the engine doesn't stop is enough to get it back to normal.
Any ideas? Lockup solenoid?
Transmission Rebuilder
Joined: Jul 2008
Posts: 1,570
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From: North Georgia
One thing it does mean is that the computer does not like what it is seeing when the converter is locked up.
The computer will monitor the converter slip and if it slips enough to fall out of a acceptable range enough times the computer will set a code turn on the CEL or OD light and disable lockup, cycling the key resets the computer to watch the converter and it repeats the failure all over again.
Most likely the converter is slipping due to a internal leak in the lockup hydraulic circuit, it can be with the valve body or solenoid or the converter itself.
I rarely have to replace the solenoids on these but I do see a lot of converter and valve body issues.
The computer will monitor the converter slip and if it slips enough to fall out of a acceptable range enough times the computer will set a code turn on the CEL or OD light and disable lockup, cycling the key resets the computer to watch the converter and it repeats the failure all over again.
Most likely the converter is slipping due to a internal leak in the lockup hydraulic circuit, it can be with the valve body or solenoid or the converter itself.
I rarely have to replace the solenoids on these but I do see a lot of converter and valve body issues.
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Cross-Country
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Thanks jk!
I understand what you are saying. Makes sense. Trying to narrow down the problem a bit:
-Code 741 is often caused by low apply pressure. Could be worn TCC valve bore?
-Leaking valve body? Doing a wet air test with proper adapter?
-Converter itself?
-TC solenoid (not likely as stated)
-Worn CCS valve (not likely as it shoud take away several gears)
Everything other than the lockup works great in this trans. Other than disabling the lock up I notice that it is somewhat slow/late to engage the lockup - like it needs some time with steady light pedal at normal speed to engage lockup.
I need help to decide where to start eliminating causes.
I understand what you are saying. Makes sense. Trying to narrow down the problem a bit:
-Code 741 is often caused by low apply pressure. Could be worn TCC valve bore?
-Leaking valve body? Doing a wet air test with proper adapter?
-Converter itself?
-TC solenoid (not likely as stated)
-Worn CCS valve (not likely as it shoud take away several gears)
Everything other than the lockup works great in this trans. Other than disabling the lock up I notice that it is somewhat slow/late to engage the lockup - like it needs some time with steady light pedal at normal speed to engage lockup.
I need help to decide where to start eliminating causes.
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