That can equally be lack of engine torque from other issues.
When it's the conductor plate it usually won't change gear at all and will sit in 3rd.
What are you scanning with?A scan just isn't picking anything up at all sadly.
If it’s the 5g 722.6 the cheapest basic check is to see what the gearbox atf level is . Also when was the last filter and gearbox atf service .A scan just isn't picking anything up at all sadly.