TRNW-2: 4L60E with SSB code

[Tod Chretien]

Group,

I have this 1999 Silverado with a P0758 SSB circuit code.

The solenoid resistance is 21 ohms.

With my scope hooked to the SSA and SSB control wires along with a 
battery ground, both solenoids have .4 volts when commanded on, which 
seems a bit high. Like the ground the PCM is providing isn't good enough.

When the solenoids are off I have battery voltage flowing through them, 
which eliminates the ignition switch.

The code actually sets on the 2-3 shift which is delayed. While 
monitoring the shift solenoid control circuit on a scope, SSB voltage on 
the 2-3 shift goes from .4 volts to battery voltage really slow. Usually 
the change from on to off is instantaneous. I have never seen one 
release the ground so slowly. The transmission eventually makes the 2-3 
shift when the SSB voltage finally reaches battery voltage, but the 
P0758 code sets and then it has 3rd gear starts. Until you cycle the key 
which starts the whole process over again.

As anyone seen anything like this? Am I correct to assume it's the PCM?


-- 
Best Regards,
Tod Chretien
TRNW Inc.
https://www.trnw.net