![]() The line pressure control solenoid code of the other computer is a bit worrisome. Compare the voltage to TCC Apply, Engine RPM, Engine Load, any kind of TCC Slip or Trans Input Speed, etc. I'd say the next test is to backprobe the TCC Solenoid Control wire at the ECM in a graphing multimeter on the Verus at the same time as watching live data. I like to do this drive cycle test first because it's easy and helps me stay on track when I'm doing under the hood tests.Įlectrically you've tested the ECM harness down to that solenoid ground and everything checks good electrically. If the TCC is electrically fine but the solenoid is mechanically damaged/restricted or there is a loss of hydraulic pressure then you can get a TCC Performance Code. This test gives you a chance to test the mechanical/hydraulic side of the TCC. Chrysler calls it an Electronically Modulated Converter Clutch (EMCC) so they usually have a pid that says not applied/partial EMCC/full EMCC.But either way, with the TCC fully applied you should see less than 10 RPM difference between the converter impeller (Engine RPM) and converter turbine (transmission input speed). If it's pulse width modulated then you'll usually have a TCC % PID or the TCC PID might say not applied/partial/fully applied. If it's an on/off solenoid then the PID will usually say applied/not applied. You'll also want to make sure the TCC is fully applied. In which case you'll have to subtract that from Engine RPM speed to get your TCC Slip. Sometimes you'll get a data pid that says TCC Slip RPM or other times you'll get an Input RPM or Turbine RPM speed. You just have to hope the scantool gives you data for TCC slip. I like to park my butt in the driver's seat with a computer on my lap for as long as I can. Whenever I have a TCC issue the first thing I like to look for is TCC slip when it applies on a road test. I'm not sure how other brands work in these scenarios. Again, I'm not picking on Snapon, I'm just mentioning them because they're what I use. When this happens Snapon scantools don't always warn you this is happening. You start flagging ABS codes and a lot of vehicles will deny you transmission bi-directional controls. If you want to do the test properly in a shop then you need a 4 wheel dyno. I also never trust transmission bi-directional tests when a car is on a hoist. They are PAPER thin! Worst case scenario is the converter grenades sending metal through the tranny then you're looking at a whole new transmission. Automatic tranny clutches are holding members. You start applying the TCC at low speeds then best case scenario you burn up the clutch and need a new torque converter. Newer vehicles are very cautious about giving you control of that. So you don't accidentally hit 1st at a high speed and start burning things up. That's why they don't let you do the test at a higher speed. As long as you're at a low speed then it won't harm anything. It's not any different than requesting a different gear. As long as you're at a low speed, or KOEO, then for the most part they don't care if you toggle a solenoid one at a time. ![]() Shift solenoids are a lot more forgiving though. I thought I had a relay problem until I realized it was just the scanner intentionally pulsing it on and off. Totally threw me for a loop the first time I was trying to test a fan bi-bidirectionally. Also Snapon likes to pulse output controls. Even running and meeting every criteria I've had a few not allow me to run the tests. They give you a list of like 8 different criteria you have to meet to command any of the solenoids. Mid 2000s and newer Fords are the worst for that. Especially KOEO and especially TCC solenoids. I don't know if it's the same other scantools but trying to do transmission bi-directional controls with a Snapon product is not a fun task.
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