po770?
- Thread starter Supra725
- Start date
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EatonKyleH
New member
having diagnosed this code for several customers over the years I can tell you its one that often has many outcomes and it's difficult to make a blanket statement as to what it is in your case.
Also to accurately and effectively test you need a scan tool capable of commanding the solenoid on/off.
the basic testing:
1. Monitor the lockup operation of the transmission. When the solenoid is turned on, the engine RPM should drop 100-200 RPM within 5 seconds. When the solenoid is turned off, the engine RPM should rise 100-200 RPM. Repeat several times to check the solenoid.
2. Check the transmission fluid for being old or dirty.
3. Flush and fill the transmission with new fluid.
4. Perform technical service bulletin procedure EG024-02 if the vehicle is within the applicable vehicle identification number range.
If the ECM engages the lockup converter but does not see the engine RPM change, it will set this code.
Also to accurately and effectively test you need a scan tool capable of commanding the solenoid on/off.
the basic testing:
1. Monitor the lockup operation of the transmission. When the solenoid is turned on, the engine RPM should drop 100-200 RPM within 5 seconds. When the solenoid is turned off, the engine RPM should rise 100-200 RPM. Repeat several times to check the solenoid.
2. Check the transmission fluid for being old or dirty.
3. Flush and fill the transmission with new fluid.
4. Perform technical service bulletin procedure EG024-02 if the vehicle is within the applicable vehicle identification number range.
If the ECM engages the lockup converter but does not see the engine RPM change, it will set this code.
Sierra946
New member
P0770: solenoid valve SL.
Check solenoid valve SL operation.
PREPARATION:
(a) Remove the oil pan.
(b) Remove the shift solenoid valve SL.
CHECK:
(a) Applying 490 kPa (5 kgf/cm2, 71 psi) of compressed air,
check that the solenoid valve does not leak air.
(b) When battery voltage is supplied to the shift solenoid
valve, check that the solenoid valve opens.
If either one fails replace.
The solenoid valve SL is the one on the drivers side closest to front of vehicle.
Check solenoid valve SL operation.
PREPARATION:
(a) Remove the oil pan.
(b) Remove the shift solenoid valve SL.
CHECK:
(a) Applying 490 kPa (5 kgf/cm2, 71 psi) of compressed air,
check that the solenoid valve does not leak air.
(b) When battery voltage is supplied to the shift solenoid
valve, check that the solenoid valve opens.
If either one fails replace.
The solenoid valve SL is the one on the drivers side closest to front of vehicle.
This happened to me today I have 209,000 on my TR4 2001 SR5. Drove about 150 miles home with this same error code. Hopefully it's a repair that will not break the bank.
Supra725
New member
as much as i hate to say it..
I tried switching my solenoid hoping that was the problem..but it turned out it wasn't..
it was the torque converter..
check out my thread for the nightmare i had to deal with the shop.. I'm close to 2 weeks without my rig and hopefully on monday i get my rig back..
with everything.. i'm looking at about $1700 for the rebuild + labor otd..
it sucks, cause the torque converter is sandwiched between the transmission and the engine.. is an pain in the arse..
I tried switching my solenoid hoping that was the problem..but it turned out it wasn't..
it was the torque converter..
check out my thread for the nightmare i had to deal with the shop.. I'm close to 2 weeks without my rig and hopefully on monday i get my rig back..
with everything.. i'm looking at about $1700 for the rebuild + labor otd..
it sucks, cause the torque converter is sandwiched between the transmission and the engine.. is an pain in the arse..
