Chevy Express Van 4500 Cutaway P0135 Code: Crankshaft Position System Variation Not Learned During EURO6 WHTC Emission Test

Hello, I'm currently facing a technical issue with my Chevy Express Van 4500 Cutaway during an engine dyno emission test under the EURO6 WHTC (World Harmonized Transient Cycle) mode. Vehicle Details: - Vehicle: Chevrolet Express Van 4500 Cutaway - Emission Test Standard: EURO6 WHTC - Engine Control Module (ECM): A 'Testing ECM' is being used — it matches the original engine's calibration but is not the factory-installed unit. - Vehicle Adaptive Learning Status: VAT (Vehicle Adaptive Testing) has been enabled. Issue Summary: - The vehicle consistently shows DTC P0135: "Crankshaft Position System Variation Not Learned" from the start of testing. - Additionally, a U0140 code appears: 'Lost Communication With Body Control Module'. Testing Procedure: I attempted to perform a Crankshaft Position (CKP) relearn using MDI2 via GDS2 while the engine was idling on the dyno. All required conditions were displayed as green ('good to go'), but the process failed and returned the following error message: - Top: Device Limits Exceeded - Middle: Malfunctions Present or Enable Conditions Not Met - Bottom: Engine Control Module After the relearn attempt, DTCs P0315 and U0140 remain active. My Questions (with reference numbers for clarity): 1. Does DTC P0315 impact the emission test result? Can I safely ignore it? 2. Does DTC U0140 affect the emission test outcome? Should I disregard this code? 3. Why does CKP relearn fail during the dyno test, even when all conditions are met? Is U0140 directly responsible for this failure? 4. Before removing the engine from the vehicle for dyno testing, can I perform a CKP relearn using the 'Testing ECM' while connected to the vehicle (before engine installation)? Would this avoid needing another relearn on the dyno? I apologize if the post is lengthy — I've included as much relevant detail as possible. Please answer each question clearly with its number, e.g.:\nQuestion 1: P0315 may affect emission test validity because it indicates a failure in crankshaft position sensing. This code typically requires resolution before passing emission standards. It should not be ignored. Thank you for your help.