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2001 DTS(140K), 2000 ETC(284K), 1990 allante( 80K)
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1,915 Posts
Discussion Starter #1
Hey there. well i have the TCC codes 0741 and 1860.
i know all about it so no need to inform me on just whats up.
however.
i got the code driving home one day. i got the 741 and 1860.
i cleared the code and now all i have is 1860. i have put 400 km on it and 1860 is the only code that shows up.
my tranny is slipping in 4th i can tell you that however not as much as it was when the 0741 code was present.

why would the code leave and not come back ?
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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6,738 Posts
Trust me it will come back. The computer has to see a certain amount of time that it acts up, so a longer drive will probably reset it sooner rather than later.
 

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Cadillac 2000 dts,1994 deville
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4 Posts
I have a 2000 Cadillac DTS that had the TTC Solenoid replaced 50,000 ago that cost $965. I recently ran the codes following a "Service Engine Soon" light and read an 0741 and a 1860. I cleared the codes and the "Service Engine Soon" light stays off for a week or longer. The tachometer reads 2100 rpms at 65 miles per hour and when going up an incline the tachometer will move up to 2400 rpms and when leveling out back down to 2100 rpms. When I drive above 65 miles per hour the rpms dont vary up or down and right away the "Service Engine Soon" light will come back on. lt is obvious the TCC Solenoid is working below 65 MPH but not above. Can anyone explain why it don't lock in and out above 65 MPH? Driving below 65 MPH results in 21 to 23 MPG. Above 65 and 70 MPH my mileage decrease to 18 to 19 MPG. Why do the codes come back under the explained conditions?
 

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Super Moderator
2010 DTS
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87,545 Posts
The TCC solenoid should engage at 41 MPH and should not disengage until you touch the brake pedal. I have no explanation as to why it would disengage above 65 MPH.
 

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2020 XT4, 70 Cougar conv, 2002 DTS
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862 Posts
Why do the codes come back under the explained conditions?
The P1860 code comes back because PCM tests are finding a continuous open, short to ground, or short to battery voltage in the TCC solenoid circuit. It is usually an open caused by a burned out solenoid switch &/or switch lead, but can be intermittent as the burned parts can sometimes still make good contact for short periods.

In other words, the PCM senses that the solenoid circuit is not ordering the solenoid to work when it is supposed to. The solenoid is supposed to cause the TCC to lock-up. 2 consecutive trips like this will trigger the SES light.

The P0741 code comes on when the PCM measures slipping for a given torque above allowed limits, when the TCC is ordered to be on. Again it takes 2 consecutive trips with this result to trigger the SES. Trips around town at low speed (below 41 mph) will not trigger the test for P0741.

So it often takes a few days to a week to get enough trips with the right conditions to get the SES to set. Pretty common.

The test for P0741 is not supposed to run if P1860 is set first, but
it seems that the test for P0741 just runs first some of the time.

Never heard of a TCC working below 65 mph & not above. But all it takes to set the codes is for it not to be working sometime when it is supposed to be on, at any speed over 41 mph.
 
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