Chekov wouldn't have a reason to look at line upon line of abstract software in the coordinating department when he's studying circuit status.
And that is not what he is asked to do. Why do you think he was told to look at software as it is not in the dialogue?
The heroes aren't in the dark about where they are, either. They have serious problems turning the ship around to where they want to go, though. It only sounds natural that Chekov would be studying the very part of the navigation system that physically turns the ship around... The part that now has been rendered inactive, so that nothing done with the helm will cause the ship to turn around.
Which is why he would not be looking at a diagram of "warp engines and reactors".
There would be a difference between looking at the controls to the propulsion system and the power system that powers the propulsion system.
- As per the dialogue, he was verifying if the "automatic helm navigation circuit relay" was actually disrupted.
- He was not verifying the power output of reactor #3 or warp engine thrust output.
Remember, Scotty thought he was breaking a connection between M5 and the automatic helm control circuit which sounds like a fancy way of saying "autopilot controls" and he was relying on whether that circuit was powered. He wasn't staking what he knew on whether braking thrusters were powered.
Now, if you were trying really hard to convince yourself that the diagram is a warp engine AND reactor display then you can ignore the dialogue call it what you want.
- That diagram does show up in other episodes so Chekov might actually be looking at the various lighted buttons around that station and in order to get the status of the circuits turn on the warp engine and reactors display to get a reading.
- Of course, you'd have a stronger argument if there was an episode Scotty or an engineer was looking at that same diagram to confirm a warp power or reactor status.