How to Unlock e38 GM tuner locked ecu with topdon j2534

Short version: the Topdon J2534 isn't going to get you there for this job, and neither will an in-car OBD approach while the ECU is still tuner-locked.

Two separate problems here:

1. Generic J2534 vs the tuning platforms
HP Tuners and EFILive don't work with third-party pass-through interfaces for GM E38 read/write. HP Tuners requires an MPVI2/MPVI3, and EFILive requires FlashScan/AutoCal. A Topdon (or any generic SAE J2534 box) will do standard diagnostics but won't flash an E38 through those apps, so "use the Topdon instead" isn't a valid substitute regardless of the lock.

2. The tuner lock itself
A tuner-locked E38 generally blocks flash access over OBD entirely — you usually can't read or write until the lock is cleared. So even with the right interface, OBD-in-car won't remove it. Your realistic paths:

• If it was locked in HP Tuners, the cleanest route is proof-of-ownership through HP Tuners support, or getting the original tuner to release it.
• If it's beyond that, an E38 bench unlock (bootloader read of the processor) removes the lock, but that means pulling the ECU and opening it — which is exactly what you said you're trying to avoid.

To point you at the right next step, a few details:

• Which platform locked it — HP Tuners, EFILive, or something else? (Do you get a specific error/message when you try to read?)
• E38 hardware and software IDs if you can pull them with a basic scan.
• Vehicle year/model the ECU came out of, and whether you have ownership/tune history on it.

That'll tell us whether this is an unlock-request situation or a bench-only job.