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Topic
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1996 chevy k1500 4l60e
The other morning when I got up to go to work I started my truck as usual and let it run for a minute or two before leaving. I noticed that my check engine light had come on very soon after starting the truck. I have a scan gauge two and it said that I had a p1860 code. I didn’t have time to figure that out so I tried to clear it to see if it would go away. But it came right back almost instantly. So I left and noticed that my truck shifted quite hard and not normal.
After driving a fe minutes the light was really bugging me so I cleared it again and it didn’t come back and it started shifting normal. I haven’t seen the code since and it doesn’t shift nearly as hard any more. However it does seem to hesitate to shift down and sometimes shifting up once in a while. I’m pretty sure it’s not slipping it will spin the tires pretty easy.
The code apparently means that the circuit to the torque converter clutch pulse modulation solenoid is having problems or that the solenoid is. Does any one know more about this? It seems to have more issues shifting when it’s cold. And the fluid looks good and doesn’t smell burnt but it probably wouldn’t hurt to change it.
Thanks!
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Replies
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Problem:
When the PCM detects a continuous open, short to ground or short to power in the TCC PWM solenoid valve circuit, then DTC P1860 sets. DTC P1860 is a type B DTC.
Possible Causes:
– Faulty Torque Converter Clutch Pulse Width Modulation (TCC PWM) Solenoid
– Torque Converter Clutch Pulse Width Modulation (TCC PWM) Solenoid harness is open or shorted
– Torque Converter Clutch Pulse Width Modulation (TCC PWM) Solenoid circuit poor electrical connectionElectrical:
Suggestions:
TCC solenoid appears to be ground switched via the “T” pin. It is supplied with a constant source of 12v power from the “E” pin. First, test and make sure you have source voltage power at the “E” pin (this may be tied into the ignition, turn the key to the ‘RUN’ position.) Next, ohm check the ground circuit for continuity as well as unwanted resistance (the ASE spec is .10v voltage drop.) Now try dropping the transmission pan and disconnect the transmission electrical connection. Jump the respective “E” pin connections together so that the solenoid is supplied with power. Next, apply ground to the “T” pin. You should be able to hear a clicking sound. If no click, then replace solenoid. If the solenoid does click, then you must test the associated electrical circuit for faults.
*Another test you could perform at this point could be to unplug and ohm test the solenoid itself for continuity.
Eric has a nice video here on how to perform these electrical tests.
4L60E Valve Body:
Failure to resolve this issue may result in premature wear or possible damage to the torque converter. In this case, it would be advised to totally disconnect electrical connectivity to the TCC solenoid to eliminate TCC lock-up, resulting in reduced fuel economy.
here is a little more help for code p1860
A lot of good information here. I’ll just add this.
http://www.ericthecarguy.com/faq/solving-transmission-problems
Good luck and keep us posted.
hey thanks for the info! i have been reading as much as i can on it, however i have not had any problems since that one morning. no codes or hard shifts or anything. in fact it feels to me as though it shifts better and smoother. I am still a little suspicious though things like that usually dont just mysteriously disappear. but also im working part time and getting ready for college so im not really sure what direction to head :/
Electrical problems can be intermittent like that. Perhaps the problem has corrected itself. Keep us posted if that’s not the case.
If it does it again…check the voltage at the TRANS fuse (#20)in the inst panel fuse box. If the voltage is lower than 13-14 volts, check the ignition switch.
I just thought I would give a quick update. I still have not had this problem reappear or had any hard shifting. everything seems to be working just fine now 🙂
Great! If you don’t mind I’d also like to recommend this manual which was recommended to me and downloaded here. http://www.4l60eguide.com/. It is a complete guide and it has helped me a lot. It has a ton of information in it that helped me
rebuild/repair 4l60e transmission. It also includes useful diagrams and pictures, plus diagnosis and repair solutions. It might help you in the future.Hello guys, I’ve being follow this “code 1860” in my ’98 yukon (4l60e). I already tried everything that is posible to found in the web… and please, now I’m at the point of completely lost.
I check all the fuses relates to the tranny, same.
I changed the TCC PWM solenoid, same.
I check resistance in new solenoid, it’s ok.
I tried direct power 12v to pin “E”, same.
I check continuity in harness, it’s ok.
I even cut the brown wire on pin 7 Red connector at the PCM and install a temporary connection to a solenoid with a 12V supply (4 inches from the PCM)… and SAME… THE CODE CAME BACK!!! (after, I also tried with a light bulb with the same ohms as the pwm solenoid… and same)
Please advise… I’m in front of a bad PCM??No other codes, transmission shifts fine…. only code 1860…and of course, no OD or lockup …and I do a lots of highway.
Thank you in advance
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