Electrical gurus...Please check this out

[68ChargerJMP]

I just bought a 99 Limited Monday. I bought it knowing there was a possibility it may need a transmission. He said second gear was gone. I got a smoking deal. Anyway, I drove it and noticed it shifted from 1-2 ok sometimes and would hesitate/slip on the 1-2 other times. He also said the gas gauge is erratic. I did some digging on here and noticed the gas gauge problem is a common issue among 99-00 4runners. Last night I drove it to a friends house a couple miles away. It shifted fine then started hunting/slipping again. It is throwing a P0758 code, which is a solenoid "B" Electrical. Not sure exactly what that means but I figure I will replace all three solenoids while I'm in there.

Here is the interesting part...I noticed that when the gas gauge is reading correctly, the transmission shifts and acts normal. When the gauge goes to "E" all of a sudden, that is when the transmission starts acting up. I'm gonna test this theory a couple of more times, but I'm pretty sure there is a pattern here. When I drove it back home, the gas gauge never dropped and the trans shifted normally all the way home.

Any insight here guys? Thanks.

 

[Silver Supra]

Was this a flood vehicle?

 

[68ChargerJMP]

No. It is a pretty clean one. He's owned it for the last 5 years or so. He said Saturday morning is when the transmission went south on him. Not sure when the gas gauge started freaking out. Timing belt was done at 232k, sitting at 262k now. Fluids all look good. It appears he spent some time and money to keep it maintained.

 

[thegipper]

You can try disconnecting the shift solenoid connectors at the tranny (outside of the tranny, not the connections on the inside) and try manually shifting through the gears.

This is a test procedure in the FSM to isolate if the shifting problems are related to the solenoids or not. By manually shifting through the gears and having the solenoids disconnected, you will know for sure if its the solenoids. If it shifts fine when done manually, you at least know that the transmission is physically ok.

I also believe one of the last possible causes of erratic shifting according to the FSM, is the ECM itself. That could possibly explain your funky electrical problems but I'm not sure how the fuel level gauge works and if it involves the ECM or not.

If it shifts fine manually, you can drop the pan and pull the shift solenoids and bench test them. There are procedures in the FSM for doing it (ohm check, 12v power test and a pressure test).

 

[IBallEngineer]

Also try using the ECT button and select power, if you notice a change then the problem is more likely a dirty filter/oil. This was the case in my Tacoma. Are you getting a flashing "overdrive off" light?

 

[spartacus]

'it wouldn't hurt to make sure your grounds are good. bad grounds cause weird issues.

 

[68ChargerJMP]

You can try disconnecting the shift solenoid connectors at the tranny (outside of the tranny, not the connections on the inside) and try manually shifting through the gears.

This is a test procedure in the FSM to isolate if the shifting problems are related to the solenoids or not. By manually shifting through the gears and having the solenoids disconnected, you will know for sure if its the solenoids. If it shifts fine when done manually, you at least know that the transmission is physically ok.

I also believe one of the last possible causes of erratic shifting according to the FSM, is the ECM itself. That could possibly explain your funky electrical problems but I'm not sure how the fuel level gauge works and if it involves the ECM or not.

If it shifts fine manually, you can drop the pan and pull the shift solenoids and bench test them. There are procedures in the FSM for doing it (ohm check, 12v power test and a pressure test).

It shifts fine auto or manually as long as the gas gauge is not spazzing out. Thanks for the input

 

[68ChargerJMP]

Also try using the ECT button and select power, if you notice a change then the problem is more likely a dirty filter/oil. This was the case in my Tacoma. Are you getting a flashing "overdrive off" light?

I usually keep ect on but I'll check to see if I notice a difference. No flashing od light. The fluid is clean as can be. I'll know more about the filter when I drop the pan.

 

[68ChargerJMP]

'it wouldn't hurt to make sure your grounds are good. bad grounds cause weird issues.

Which grounds do I check other than the gaggle by the intake?

 

[Silver Supra]

Which grounds do I check other than the gaggle by the intake?

As many as you can find.

 

[spartacus]

which grounds do i check other than the gaggle by the intake?

 

[spartacus]

 

[octanejunkie]

The intermittency sounds like you might have a short in your wire harness somewhere.

I would visually inspect all wiring under the vehicle and engine/transmission looking for worn insulation, possibly even animal/rodent damage.

Luck

 

[spartacus]

rear grounds

 

[phattyduck]

Another possibility that I have been experiencing (and have the parts to fix, as of yesterday) - a problem with the circuit board on the back of the gauge cluster.

My errors have been P1780 and at separate times the left turn signal would activate the reverse lights...

I say this because, like grounds, the gauge cluster is about the only place the gas gauge circuit and the transmission control circuitry comes near each other.

-Charlie

 

[68ChargerJMP]

Well, I think it was just a coincidence. I drove around some more and the gauge drops if you accelerate quickly, which is probably the sending unit. My VIN falls under replacing the pump/sending unit and circuit board on the cluster, according to the tsb. The shifting issue seems intermittent on its own. Would the shift solenoid b electrical(P0758) cause slipping and sometimes shifting from 1 to 3 , skipping 2? Once it finds a gear , it won't slip under hard acceleration at all, only between gears. Thanks.

 

[68ChargerJMP]

Well, I changed all three shift solenoids. It is still throwing a CEL P0758 and still losing second gear. What is my next step? Do I ohm out the wires between solenoid b and the ECU? it drives great in first, third and od, it's just second gear that is having issues. I don't want to rush into swapping in a transmission if it's an electrical/ecu issue. Please advise guys. Thanks.

 

[68ChargerJMP]

Where exactly is the shift solenoid wire harness located externally on the transmission? Thanks.

 

[68ChargerJMP]

Bump for a little advise here. Thanks.

 

[spartacus]

Bump for a little advise