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  1. P

    rough shift 1st to 2nd: fast service learn

    @NickTransmissions any thoughts on what could be failing here? i haven't confirmed that this isn't a TC problem, but i wouldn't expect it considering this issue appears isolated to the 1-2 shift.
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    rough shift 1st to 2nd: fast service learn

    i believe i have a characterization of the valve solenoid behavior when the transmission slips after some observation with gds2. when in 1st gear, i see shift pc solenoids 1, 3, and 5 at ~2200 kPa (rest at 0), and in 2nd gear, i see 1, 3, a 4 at ~2200 kPa. pressure on 5 drops to 0 as pressure...
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    rough shift 1st to 2nd: fast service learn

    did some furthering reading and found a relevant section in the service manual titled "symptoms - automatic transmission". the service manual pdf i have only covers the 6 speed trans, but most of the general content is clearly relevant to the 10 speed trans. the details obviously change between...
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    fuel injector voltage probe location

    sorry about that, i've updated the link. pardon the cut-and-paste error.
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    fuel injector voltage probe location

    ah, this is actually expected behavior per this video from phillip bailey. the top comment claims that these pressures are supposed to be compared within each bank, not across all 8 cylinders, which makes sense. however, the gm service manual does say to compare the pressures across all 8...
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    fuel injector voltage probe location

    i finally got around to doing an injector balance test with mdi2+gds2 and i got some surprising results. bank 2 pressures show as being a flat 50% higher than bank 1. the results for all injectors (in kPa) are: 1 - 173, 2 - 299, 3 - 194, 4 - 292, 5 - 202, 6 - 310, 7 - 176, 8 - 299 i have read...
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    rough shift 1st to 2nd: fast service learn

    afaict, it's a rough shift from 1st to 2nd, where the rpms "flare" upwards during the shift and the tires chirp a bit. i'm not sure what the ideal way to confirm this would be, e.g. monitor the shifting using mdi2+gds2. i checked the level for the trans fluid and it was a bit low (0.25-0.5 qt)...
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    rough shift 1st to 2nd: fast service learn

    i used the cgsulit sc530, my cheapest scan tool, to do the fast service learn. the shifting issue is substantially improved from earlier, but it still misses every so often. i will update after another few 100 miles of driving if it sorts itself out. if the problem persists post-fast-learn, i...
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    rough shift 1st to 2nd: fast service learn

    i've recently done a dod delete, and i also did a transmission fluid flush and filter change. the vehicle had the battery disconnected for long periods of time, and i experienced battery problems to the point i had to replace the battery a few days ago. i am experiencing missed/rough shifts from...
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    reset steering angle sensor problem - SOLVED

    it ends up that attaching the new sensor did not clear the c0710 and c0544 codes. i pulled the steering column, replaced the sensor, reinstalled the steering column, and then i was able to do a sas relearn successfully from my xtool d8s. the sas relearn cleared the c0710 and c0544 codes and...
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    reset steering angle sensor problem - SOLVED

    after connecting the new sensor, i have noticed that the steering angle dtcs (c0710 and c0544) have gone from current to history, which i assume indicates they are no longer active. i will remove the upper steering column, install the new sensor and see how things go.
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    2020 6.2L: misfires, lifter issues and engine replacement - SOLVED

    hah, i'm on month 4 of repairs, but i'm just fixing up the last bits now (dead steering angle sensor and related dtcs).
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    reset steering angle sensor problem - SOLVED

    i grabbed a replacement sensor, part 13590209, from the local dealership, and i have confirmed that hp tuners mpvi3 can see live angle data from the replacement sensor, whereas it cannot see any live data from the installed sensor. the mpvi3 does not support sas reset or learn, and neither of...
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    reset steering angle sensor problem - SOLVED

    i cannot get steering angle sensor data from either of the 2 scan tools listed above nor hp tuners mpvi3. am i right to say that the steering sensor needs to be aligned similar to the clock spring, meaning i may have to recenter it manually? i see videos about replacing steering sensors...
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    reset steering angle sensor problem - SOLVED

    appreciate the reminder to rtfm. the service and repair manual i have suggests doing 2 things to address the C0710 code: first, use a scan tool to read the steering wheel angle and confirm it varies continuously over its full range (-550 to +550 deg), then perform the sas recentering procedure...
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    steering column out of alignment after removing steering gear

    after removing the steering gear and confirming it was indeed properly centered by marking the stops and the center, i reinstalled it yesterday and reconnected the rest of the steering column and steering wheel. surprisingly, i found that after reinstallation of the steering gear, the large...
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    reset steering angle sensor problem - SOLVED

    i have completed a deep engine repair (failed piston rings), and i am struggling to get past the issues i'm having with the steering system. i had a major misalignment with my steering gear, fixed it, got the steering column lined up properly, adjusted the inner tie rod bolts to set the toe, and...
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    fuel injector voltage probe location

    i was looking to get the live waveforms from this vehicle in particular, but it's not a huge deal if i can't access the injector ground wiring. appreciate the pointer to do an injector balance test because that accomplishes what i was after with less work. it looks like most decent...
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    fuel injector voltage probe location

    having recently repaired a failed set of piston rings on 1 cylinder, i'm trying to improve my diagnostic skills and evaluate a hypothesis from @Pressureangle about the corresponding fuel injector having a problem, e.g. opening for too long relative to the other cylinders. i've got a picoscope...
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    2020 with slight vibration at idle

    any time there are misfires, you should get a scan tool and check the dtcs. when i was having regular misfires on 1 cylinder, the ecm would increase the timing advance until it would drop back to zero and repeat. it created a sawtooth pattern for engine rpm, where it would surge up to 700 then...
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    2017 LT Tahoe 5.3 Randomly Starting

    i assume you don't see a battery icon when you attempt to start the engine and it fails. without some indicator that the battery is low, the fact that it powers up suggests your battery is ok. the best way to test the battery is a simple battery tester, e.g. ancel BA101 tester. if the battery...
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    2018 Yukon 6.2 strange sound - SOLVED

    i recently had a consistent misfire on cylinder 8, and i learned the hard way that you should always do compression and leakdown tests to confirm the cause. do you have any other codes beyond the P0306 for the cylinder 6 misfire? is the check engine light solid or blinking? having spent a fair...
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    steering column out of alignment after removing steering gear

    i pulled the steering gear to check it and take some measurements. i found that it was indeed properly centered as-is, but my inference is that the game to get it aligned is to adjust the (inner?) tie rod nuts. i counted threads to the tie rod nut on both L and R sides, along with the distance...
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    steering column out of alignment after removing steering gear

    i'm nearly done with fixing this car, and i now have a steering alignment problem that has come up. with the wheels dead straight, the steering gear knuckle is notably off center, forcing the center mark on the steering wheel bolt 30 degrees to the left. when i have the wheels straight...
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    2020 6.2L: misfires, lifter issues and engine replacement - SOLVED

    UPDATE: i replaced a lot of stuff in the top of the engine, but that didn't fix the problem. ends up it was failed piston rings on cylinder 8. the engine now idles fine with no misfires. this is a reminder that you should always do a compression and leakdown test yourself before disassembling...

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