Hello everyone, I have a 2011 Prius with 2 saw cuts in my tail pipe. Would be thief ran off after my car alarm startled them. However, they'd already started cutting my pipes. I can borrow a flux welder from a friend. But what is the SOP prior to electric welding to avoid damaging sensitive electronics in the Prius? I had researched here a bit and know that I have to remove both +/- at the 12 volt auxiliary battery. Is disconnecting the High Voltage Plug necessary (it has a floating ground controlled by 12 Volt battery through ignition), I'd assume not necessary. Anything else that need to be disconnected prior to flux/arc weld? Any welders who had done this before on a Prius? Please advise, thanks..
As far as I've seen Prius problems related to electrical arcs from welding have been from body shops that had to do a huge amount of welding. Never seen muffler welding mentioned as a problem on here. But as someone who taught myself how to weld with a cheap Harbor Freight flux welder so I have a back up plan with cat replacement hassles I can tell you my plan is to unbolt the section that needs the work and do it properly without anything connected to the car. As in I don't have a lift and crawling under my car to create sparks with a welding mask on is dumb... But if I were you I'd simply wrap some Tiger patch heat reactive epoxy tape for muffler leaks around the cut marks and consider it done until other repair work gets the car up on a lift so you can fix it properly.
In Collision Repair Information Bulletin #160, “SRS Precautions,” December 2007, Toyota writes: When using electric welding anywhere on the vehicle, disconnect the 12 volt battery and the center airbag sensor assembly connectors. These connectors contain shorting pins. This feature reduces the possibility of airbag deployment due to current entering the squib wiring. In Collision Repair Information Bulletin #161, “Collision Damage Repair Precautions,” January 2008, Toyota writes: Before performing any electric welding, turn off the ignition, disconnect the negative terminal of the 12V battery, remove any ECU’s within 18 inches of weld sites, and disconnect the main SRS computer connector, waiting 90 seconds before start of welding. As @PriusCamper kindly suggests above, in this case, I’d recommend removing the exhaust pipe assembly from the car before attempting to repair it. This would let you inspect the damage properly and make the welding easier and safer. Note that the two gaskets, part numbers 17451-0D140 and 17451-F2010, are shown in catalog Figure 17-02, Exhaust Pipe, as non-reusable parts. Toyota doesn’t mention it, and if the car is off, the system main relays will be open, anyway.
My exhaust guy here locally who I've been going to for 35 years generally lifts my generation two up on the rack with me standing under there with him clamps as ground I don't know about 22 in away from where we're working usually on the pipe most of the system is supported on a rubbers except the bolt connections to the big exhaust gasket at the manifold I've never seen anyone undo these. Then he cuts the pipe that he wants to put or use to fix what he's fixing gets that squared away makes the cut on my pipe slides the piece over or whatever he's doing makes the weld fills it etc . Drop the car off I go. This is how it's gone on three times two different generation twos both attempted cat steals.
The Repair Manual for Collision Damage also recommends putting the welder's ground clamp as near as you practically can to where you'll be welding, so the current won't flow through any more of the car than necessary. ... at least, that's in Gen 1 CR manual. I haven't specifically looked in a newer one.
