Highlander Hybrid maintenance Qs

I have a 2006 HiHy 4WD-i with 30K miles. I hope the group will allow me to post a couple of maintenance Qs since the PriusChat HiHy forum has very light activity and we've got amazing Toyota expertise monitoring this forum daily...

1. When disconnecting and reconnecting the 12V auxiliary battery, the repair manual (p. IN-54) suggests that the SFI system has to be initialized. The procedure includes putting the car in inspection mode, warming up the engine coolant to 83 degrees C or more, then shifting to N and running the AC so that the traction battery SOC drops below 40%. Then force charge the battery for 30 seconds and then see if THHT shows that ISC LEARNING is complete.

• Is ISC an acronym for "idle speed control"?
• Is THHT just used to monitor the various operating parameters or does it do anything to shift the operating state of the engine ECU? (I am wondering if I can execute this procedure without having access to a THHT.)
• What happens if this initialization procedure is not followed - what driveability issues will result?
• Why is this procedure required on HiHy while Prius for example, does not require this initialization.

2. A recent discussion about Prius spark plugs prompted me to think about removing the HiHy spark plugs to inspect them and put antiseize lube on the threads. However the service clearance on the side of the engine facing the firewall is non-existent. Again consulting the repair manual (p. IG-4), it appears necessary to remove the intake air surge tank (that the throttle body is connected to) to gain the necessary clearance.

• I'm wondering whether anyone can suggest a shortcut. If no shortcut is available, I'll probably wait until the car has 60K miles before I do this.
• How many labor hours would a Toyota dealer service shop bill for removal/installation of HiHy spark plugs?
• Does the regular Highlander also require this level of disassembly to reach the spark plugs?

Thanks so much!

 

Thanks Rick & Galaxee for your comments.

The maintenance schedule requires a timing belt change at 90K miles. Many of the same parts have to be removed to access the timing belt as well as the spark plugs (which the maintenance schedule suggests replacing at 120K mile intervals).

Hence, I think I will wait for 90K miles then do a comprehensive service at that time, replacing all of the following:

• timing belt
• engine coolant pump & gasket
• timing belt idler pulleys
• iridium spark plugs (hopefully they won't be stuck by then)
• intake air surge tank gasket
• engine & inverter coolant (if I don't do those at 60K miles)