apate81

Hi guys, I'm new here. Just picked up an 88 4 runner for $500 actually runs good, but the transmission won't shift on its own. I have to start out in L and shift my way up as I gain speed. It seems to skip 2nd all together and go straight to 3rd when I shift from L to 2. It does seem to make a very weak attempt on occasion to shift itself, but most the time it'll just keep revving like a manual trans would until I shift. Fluid looks brownish but doesn't really have a burnt smell to it. It looks like the previous owner replaced the ECM. Could they have put the wrong ECM in? Maybe one for a manual trans instead of auto? Does that even matter? I had a jeep with the same issue and it turned out to be a loose ground wire.
Anyone had this experience before? I could use some advice. Thanks in advance.

Bojangles

Im really not a transmission person,
But its possible the solinoids in the tranny could be bad, which i would think would cause it not to shift correctly...

jlshaff9

If you look in the right spot on here, you'll find how to adjust the tran-throttle cable. I dealt with similar on my old '88 Auto.
Best of luck. I sold mine...

apate81

Thanks guys. I hope its something simple like a cable adjustment. I guess I should mention that when I put the truck in Drive it seems to be in 3rd gear and really bogs down the tranny. Just to get it to move I have to put it in L. I truly have to shift it like a manual. It works fine just seems to skip 2nd gear when I shift from L to 2.

4runnerx3

Sounds like the ECT unit is unplugged, the computer for the tranny. It's under the console at the front, under the radio. With it unplugged, the solenoids don't work. L is 1st, 2 is 3rd and D is OD, you will not have 2nd gear.

iamsuperbleeder

maybe it's just low on fluid?

I know you said it looks brownish (which isn't good anyway), but how's the level?

apate81

fluid level actually seems to be a bit high. i suppose i could drain a little off and try it, but it still seems like a solenoid problem. it shifts fine when I do it manually which makes the think the solenoids are not engaging. I'm not sure why they wouldn't engage though. 4runnerx3 I looked for the ECT unit and couldn't really see anything that looks like it. There is a small black relay but it looks to be plugged in. What does the ECT itself look like? Thanks

apate81

The ECT light works on the dash and seems to switch back and forth from normal to power. Doesn't seem to do anything to help the tranny though. If the lights work on the dash, does that mean the ECT is plugged in? Also the O/D light doesn't work in either position.

4runnerx3

This box is the ECT unit.

4runnerRandy

Google www.toyotaholics.com and check the link for the A340 transmission. Then thank Scotty for this great info. He is on this board also.

apate81

Thanks for all the help guys, I do appreciate. it. I'm gonna go try the ECT thing and if its not that then I'll check each sensor one by one until I locate the problem. Could take me a while, I'm a little slow with a voltmeter.

annoyingrob

Your O/D light not working is likely just a burnt out bulb. If the green "Over-Drive" text on the switch lights up, just pop out the assembly, and swap the bulbs around in the back. That will tell you if it's just a burnt out bulb.

If your ECT lights are working, that indicates that the computer is getting power, but the signals may not be getting to the transmission, causing the tranny to go into failsafe mode like you have described. You could simply have a loose connector going to it. Look under the intake manifold, there are quite a few connectors going to teh transmission. Un-plug, and replug all of them first to make sure that they're properly seated.

Does your 4-LO work? Low range is controlled by a 4th solenoid from the computer. If that doesn't work either, you might have a computer issue.

apate81

The O/D light doesn't even have a bulb in it, so that explains why it isn't lighting up. ECT was plugged in. The single red wire with a separate connector was a little frayed but still connected. 2 of the terminals on the ECT connector were getting power but I can't find my voltmeter, I just used a circuit tester therefore I don't know the exact voltage. I think the 4 Lo works I know it moved forward in 4 Lo, but I don't remember if it was truly a low gear. I'll check tomorrow. I'll check the connections on the back of the intake manifold tomorrow as well. Does anyone have a schematic of the ECT wiring? I would like to check continuity of the grounds and make sure I have power everywhere I'm supposed to. The temp gauge is acting a bit odd as well. It starts all the way in the cold position then about thirty seconds after I start the truck it jumps about half way up. Could this be part of the problem? Thanks guys.

4runnerx3

layout of plug harness

apate81

None of the plugs listed above really seem to correspond with my plugs. The bottom one looks like the larger plug that goes into the ECM but I couldn't 'get any of the wires to relate. According to the chart above I had voltage in places I shouldn't have and vice versa. The top one looks nothing like the plug into my ECT. Do I have an oddball 4 runner? I'm really confused now. I guess I should have mentioned it is a 3.0 maybe the wiring is different for the tranny between the 22re and the 3.0? 4 Lo works and all the connectors on the back of the intake seem to be connected properly. Should I have checked the connections with the computer unplugged or back probe them with it connected? I checked with it unplugged.

apate81

I also checked the engine fault codes today as the light came on while driving around. The codes were 42 and 51 best I could tell.
Code 42 is
VEHICLE SPEED SENSOR SIGNAL CIRCUIT--NO SPD. SIGNAL FOR SEVERAL SECONDS

WHILE VEHICLE IS OPERATED UNDER HEAVY LOAD (TPS/MAP/AIR FLOW INPUTS)

--SPEED SENSOR/CIRCUIT
--ECU

and Code 51 is:
SWITCH SIGNALS

IDL (tps) CONTACTS OFF, NEUTRAL START SWITCH OFF, A/C SWITCH "ON" SIGNAL TO ECU

WITH DIAGNOSTIC CHECK CONNECTOR SHORTED

--A/C SWITCH/CIRCUIT

--A/C AMPLIFIER

--TPS/CIRCUIT

--NEUTRAL START SWITCH/CIRCUIT
--ECU

any ideas? seems like these codes are relevant to the tranny not shifting but unfortunately it gives me a lot of options as to what is causing the problem. Could it be a bad ECM or ECT? The truck did shift itself into 2nd gear for just a second or two today with the shifter in L it has done this maybe 3 times total.

4runnerx3

The top pic is 22re FSM, the bottom is from a ATSG transmission book. These are the codes in the FSM for a truck with a 22RE, don't know if the 3.0 is different.

4runnerx3

The tranny works on pressure from the throttle cable, have you checked the setting on the cable at the throttle body?

apate81

I've checked, but I'm not sure what to look for exactly. The throttle cable has a little slack and the kickdown cable has quite a bit more. I tightened the kickdown cable as far as it will go, but its still pretty loose.

annoyingrob

It sounds like you have some loose grounds on your engine causing your codes.