EO39 at 35 mph

rjfranken · 2 Weeks Ago

Here's one for the books. I'm now throwing EO39 after I fixed my EO26 by reconnecting the canister purge valve. The wiring harness was so taught it worked it loose. I'm throwing EO39 under the same driving conditions. Start out cold; not even a half mile and hitting 35 mph for a couple of blocks under acceleration, release the gas to slow for a light, and at that moment (and every other time) the SES light comes on no more EO26 but now a EO39. Never hit 4th gear but driven for 30 seconds works "by the book". Watch the diag screen and I can see the TCC light go solid at speed in both 3rd and 4th gears. I'm at a major loss! I can let off the gas on a surface street and I can expect the bing bing; some times now no bing bing. Never on the freeway-ever. These conditions ran the EO26 too. 39 has always been a history till now.

Ronnie · 2 Weeks Ago

Does the TCC actually lock? Do you see the rpm drop when conditions are right for TCC lockup? If not the E039 may be set to tell you the TCC is not locking when the ECM is commanding it to do so.

RealMcCoy · 2 Weeks Ago

This is pretty old tech for me and is making me dust off twenty years of cobwebs...

The ECM doesn't know which quad driver circuit caused the E026 (could be TCC, canister purge, fan control, or EGR) so I suspect it may suspend further testing once it sets the 26. It's even possible that it disables the TCC to protect the circuit when it see the 26.

The ECM sets the 39 when the TCC is commanded on, and the expected RPM is not reached. You should see a definite decrease in rpm when the TCC is commanded on. The easiest way to test it is to drive it at speed, under a slight acceleration, with the TCC commanded on. Then lightly step on the brake just enough to trip the brake light, but not enough to engage the brakes. this will remove power from the TCC and unlock the converter. under those conditions you should see a definite increase in rpm, and feel the slight jolt as it unlocks.

If that doesn't happen, start your search at the power to the TCC... check the fuse and then the brake switch.

If the power side checks out, you can temporarily wire in a grounding switch to the control side and see if you can manually lock up the converter. That will tell you if it's in the trans or the ECM is not grounding the circuit.

Good luck.

rjfranken · 2 Weeks Ago

E026 came back. 39 has not since that day-same gas pedal feather on decel. The rpm's are as they should be. It's always something.

nic walker · 2 Weeks Ago

THis EO 26 "stuff" (I have a better word) Is for the birds.....I had it for a year, changed hoses and egr valvle but don't even know what the tcc stuff is. There are probly more of us out there that need help understanding the EO 26 mess.....Help

RealMcCoy · 2 Weeks Ago

The E026 is just a quad driver error... the ECM is is not seeing the expected current draw on the circuit...

It's pretty simple, the only difficulty in the process is that the ECM doesn't know which circuit is having the problem, so you have to test them all until you find it.

The most common issues are going to be bad purge solenoids and TCC problems, so I would start there.