# Observations, Differences between AHA and ATQ



## PhantomDubs (Sep 8, 2001)

Just finished swapping an ATQ (later 30v) engine into my 99 Passat. Thought I would document the differences I noted between the two engine codes in case anyone is looking for the info in the future.
AHA is drive by cable, ATQ is drive by wire, so the throttle bodies are different. As a result, the throttle body heater/coolant bypass hoses are different. Also, the ATQ has a different vacuum hose setup, and the stainless steel barb into the intake manifold needs to be removed and plugged as it interferes with the cable throttle body of the AHA. There is also a spacer between the ATQ TB and intake manifold that should be removed, as the AHA TB is thicker.
Coolant temp sensor on back of the engine is different, uses a different style plug and will need to be swapped out.
Knock sensor wires use different color plugs. AHA had green plugs, ATQ has brown plugs. They are interchangable, but it caught me up for a minute on reassembly. Of note, label the wires because there are a ton of three prong plugs of different and same colors that will all plug into each other, stupid of VW to not make the plugs keyed in some way.
I think thats all I noticed, but it is good to know this before the new engine is in the bay, swapping the TB out with the engine in the car would be really a PITA.


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