Check engine light with p0740 code

Last Edited By Krjb Donovan
Last Updated: Mar 11, 2014 07:47 PM GMT

Question

QUESTION: I have a 2000 Chrysler LHS with 211k miles. The car was just inspected for emissions and passed -thank God. However today after bragging about how good the car has been - the check engine light came on. I took it to have it analyzed and they said the Torque converter solenoid circuit was opened as to why I got the P0740 code along with the P0700 Transmission malfunction. The transmission has been flushed at least twice. If I don't act now, what impacts can be anticipated, and or what actions should I take now? Cant afford a car note and need the vehicle for daily work runs. Also, if I do nothing, will it pass future emission inspections if the light remains on? I hate not doing anything - but no funds and need my car!!

ANSWER: Hi Jeffery, The main thing you will notice is that the shift that occurs when you pass through the 40-45 mph range which causes the rpm to drop a bit will not be happening. That means that there will be a slight reduction in fuel economy as the result but nothing major. It may do it sometimes, and sometimes not, but other than that I don't believe that there will be any harm done by not dealing with the issue at this point in time. That kind of a fault does not prompt the transmission controller to do a more drastic response which is to only run in 2nd gear or reverse gear and that is called limp-in mode. So that also shows that it is not a condition which would cause damage if not attended to. You have gotten already more miles from the trans than most people do. At some point in the future if you find the trans in limp-in mode then you want to get a code readout and see whether the fix is something that just involves dropping out a part for replacement or removal and rebuild of the transmission. The fix for this 0740 is usually removing the trans and checking out the torque converter and the trans fluid pump condition to see which is at fault. As to passing inspection, it depends upon the state standards. Because this is a transmission issue, and not an engine pollution issue, it may not be a cause for failure, but you would have to verify that with the state auto registration rules. Just ask if a check engine light in and of itself is a cause for non-compliance or whether the cause of the light needs to be understood and evaluated. Roland

---------- FOLLOW-UP ----------

QUESTION: Roland - great information, thanks! The torque convertor solenoid circuit is suggesting the open. How difficult is it to replace to clear the check engine light - so I can be alerted should anything new pops up, which requires my attention? Also, as a precaution, I removed several pints of fluid and replaced it with a transmission cleaner and sealant from Lucas. Do you think this will help the transmission perform better and "possibly" clear the check engine light after a couple of hundred miles of driving assuming the open circuit indication may be due to dirt or debris keeping the circuit open?

Answer

Hi Jeffrey, The check engine light will clear by simply disconnecting the battery for a minute (disconnect at the - post clamp). I have no experience with the Lucas cleaner and sealant so don't know what to expect. Please let me know what happens so I can share it.

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