What can cause an E-35 Code (k21 engine)

links to the tools used in this video Piercing Probe https://a.aliexpress.com/_mMRfMqe Needle Probes https://a.aliexpress.com/_msisoMa A question was asked about what signals are preset in the LPG injector driver module. This video tries to answer that question and what can trigger an E-35 code