Hello,

I'm having this problem – code P1870 – on my 1997 Camaro Z28 5,7L V8 with an 4L60E automatic transmission. I hope you can help me.

We've tried changing the following parts to solve the problems:
- solenoinds
- engine temperature sensor
- throttlepositioning sensor
- sonax kit 77754-03K (shift from 1 to 2 gear)
- sonax kit 77805E-K (converter)

Problem is that the transmission shifts hard from 1-2-3 gear when engine temp is "normal".

Further there is a problem re. the lock up function – this function is also missing when engine temp is "normal" and therefore the revs are rather high on the highway.

I really don't know what to do – could it be an electrical problem and how do I find the components that I should try changing?

I'm looking forward to receive your suggestions.


Thanks
Thomas Krath
Copenhagen, Denmark

 

Could there be a link to this question that I've just added at the "LT1 / LT4 Engine Tech" board?

http://web.camaross.com/forums/showthread.php?t=404108

Thanks
/TK

 

The 1870 code is usually caused by a worn TCC control valve bore in the valve body. It's actually a very common problem. Sonnax Ind. makes a kit to fix it. The valve body has to be reamed, and a new valve/sleeve is installed.

Frank

 

I thought the Sonnax kits that my mechanic did install (77754-03K and 77805E-K) were the once you mention? Sonnax told him that these kits should solve the problem... Could you please supply me with the Sonnax kit numbers you mention - if possible?

Btw. the hardshift problem disappears if the ignition is turned off - however, it returns within a few miles. Further it does not solve the missing lock up.

Could the next step be to change the box/computer that controls the transmission?

According to my mechanic there is no mechanical parts inside the transmission which needs to be changed - everything looks very clean/like new!

Thanks
Thomas Krath

 

i am dealing with this same problem. i installed the sonnax kit over a year ago and rebuilt the tranny a few months ago. however, i didn't replace my TC. i think a new TC would correct this problem. it could be a few things though. have you replaced the TC solenoid? if anything sets the 1870 code then you will feel the harsh shifts due to the computer thinking that something is wrong and compensating with higher fluid pressure. there is one other thing that i am looking into. have you had any recent misfire codes set?? a random misfire can throw a 1870. it could be a random misfire with a plug, wire, coil (more likely) or a fuel injector (very possible). so, just wondering if you've seen any other ses code in recent memory.

 

YEAH - PROBLEM IS NOW SOLVED!!!

Thanks to Frank aka "12SCNDZ".

What we did was to change the following parts:
- solenoinds
- engine temperature sensor
- throttlepositioning sensor
- sonax kit 77754-03K (shift from 1 to 2 gear)
- sonax kit 77805E-K (converter)

... which did not help

After a lot of reading on this board we decided to change the valve body. Now this has solved the problem! We are so pleased! Actually this was what the mechanic suggested the first time we had the problem. However, he decided not to change it and try the less expensive parts - a huge mistake.

Never mind - problem is now solved!

Thanks
Thomas Krath
Denmark