Comparing Wave Forms 2004 Solara

mcmc116 · Post by **mcmc116** » Fri Jul 10, 2020 6:03 pm

I have a 2005 Toyota Solara 2AZ_FE egine with a u241e automatic transmission. Pulling a Code p0776 Pressure Control solenoid stuck off. I've already tested solenoid operation but since i already had the solenoid accessible i went ahead and replaced it. I used my picoscope and saved wave forms at computer for this solenoid that i will post, i also connected my picoscope and took wave forms from a known good 2004 Toyota Camry with the same engine and transmission. Comparing the 2 wave forms i can see a difference. The Bad wave form i can see the solenoid on for about 1.1ms and off for almost 2ms and compared to the good one it is almost the opposite on for almost 2ms and off for 1ms. i want your opinion, do i have a bad computer driver for that solenoid? ive checked wave forms at both the computer and connector at the transmission and they are the same.

liviu2004 · Post by **liviu2004** » Sat Jul 11, 2020 8:12 pm

Pressure control solenoid controls .... pressure? And if setpoint not achieved would the ecu .... drive it longer?

Are you blaming the exhaust pipe if the radio does not work?

Grant_Baker · Post by **Grant_Baker** » Sat Jul 25, 2020 11:28 pm

There are DTC's that point to an electrical circuit problem, and there are DTC's that point to a mechanical or hydraulic problem. The ECM did not see a problem electrically with the solenoid circuit "B"/SL2. P0776 points to a mechanical or hydraulic problem. Mechanical or hydraulic problems are identified by watching input shaft speed(NT), intermediate shaft/counter shaft speed(NC), and output shaft speed. What the PCM saw was an incorrect shaft speed or gear ratio...given the expected position of the valves related to solenoid "B"/SL2. SL2 is used to control the hydraulic pressure applied to Clutch "C2." The ECM commands higher current in this solenoid to decrease hydraulic pressure on C2 clutch(longer low portion of SL2 waveform). The ECM commands lower current in this solenoid to increase hydraulic pressure on C2 clutch (shorter low portion of SL2 waveform).

The cycle time is the same between the waveforms, as I have demonstrated by moving your vertical cursors in the following attachments.

Your "known good" 2004 shows a high/low delta of 12.7V.
Your "known bad" 2005 shows a high/low delta of 13.8V.

The voltage difference indicates the captures were taken under different conditions.

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