Automatic Conversion

[Paul Leonard]

Hi all, have a Yaris 2007 ncp91r. It used to be a manual, this is on the paperwork, and has been converted to a auto. The job was done before I purchased it. It has had a good job done as it runs smooth. However, it starts in park. I am wondering if anyone has ideas? I know there is a neutral start switch on the trans. However, its not just a simple one pole switch. Are these problematic on this model? I am also wondering about the ecu, having being converted to a auto, I am wondering if there was a need to change the ecu? Does anyone know the part number that should be on the 2007 auto? Also, I believe the manual has a clutch inhibitor switch that requires the clutch pedal to be depressed before the car can start, is this correct? I am in Australia.
Any thoughts would be useful.
Regards.

Update, sorry, the car starts in drive, brainsnap. I know this can be dangerous as the car can lurch forward, so was wanting to fix it.

[CrankyOldMan]

That's a really strange swap--most people that are willing to do all that work want a manual. I've only researched going from AT to MT, but it should apply both ways. I'm not sure what the big question you're asking is, so I'll answer what parts I can.

Starting in park: isn't that what you want it to do? The MT has a clutch switch in series with the ignition switch, the AT does not. Bypassing the clutch switch is

Neutral switch: reliable? I've never heard of one failing on any car, much less a Yaris.

ECU: yes, I'm pretty sure you'd have to put in an AT ECU to get the shifting functionality. There's a bunch of part numbers for ECUs depending on when/where it was made. Toyodiy.com is my starting point for those kinds of things. I think AUS falls under "General" market even if they're made in Japan. Pick the appropriate details for your specific model, click on the link for that configuration and look under "Electrical->Electronic Fuel Injection System->Computer, Engine Control" for the part number(s).

[Paul Leonard]

Yikes, sorry, it starts in drive, my mind got a little scrambled.

I know this is dangerous, as the car can lurch forward,

So I want it fixed.

I will check the web site you suggest. Also am unsure about simply changing the ecu, can this just be swapped, I know its just under the bonnet and there are two plugs, thats easy. But what about things like the security system. Will the car start given a new ecu?

Thanks for your reply

Update, used the site you suggested, its great, got the info I needed, it suggested a 89661-52C30 for the ecu, and, thats whats in the car. Been looking on eBay and trying to work out from the different listings what should be in it, and, this was the part number that although not always came up, consistently did, so it looks to be the right part. I guess then I may be able to let the ecu alone. It must be somewhere else, the neutral start switch or something else.

I also believe there is a adjustment on the neutral start switch, have had a look at it on the car, and, it seems to line up as there is a pointer on it. Was wondering just how precise this needs to be.

Also, have no idea what is on the shift mechanism in the console?

Not sure I can say ebay here?

Was able through this website, to check the vin number, and, yes, for sure the car used to be a manual.

Again, thanks for directing me to the site and your input.

[stidnam]

Yeah it's not an uncommon conversion here in Australia to swap a Yaris from Manual to Auto. Most manual versions will sell for a couple if not a few thousand less than an Auto.

I don't actually think the car would drive without the auto ECU. The auto ECU controls the gearbox as well, and it seems like you've confirmed that it's an auto ECU anyway.

The difference between a manual and auto in respect to the starting circuit is that the manual has a clutch start switch, while the auto most likely has the equivalent wire running through the park/neutral switch assembly, which should mean that being in Park or Neutral it acts in the same way as pushing the clutch in to complete the circuit in a manual car. Therefore, i'm speculating that someone has done the dodgy and perhaps permanently wired the clutch start switch closed instead of hooking it up to the appropriate neutral/park switch.

My first suggestion is to hop under the dash where the clutch once was and look to see if you can identify the wiring that would have run to the clutch start switch and trace that to see where it goes.

[Paul Leonard]

Hi,

yes, I went through the service manual and it suggested the wires should be black and yellow. Am unsure what they have done, but the plug going to the clutch pedal has been cut off and the two wires have been twisted together, not with a joiner or anything, just stripped and joined. I was going out today and didnt attempt to separate them.

Will do it in the morning. I am pretty sure at this point that these wires would have led to the clutch and were in parrallel with the neutral start switch.

Not sure why someone would have done this. Doing all the other work to install the trans, why would they just join these up?

Hoping I will just separate them and the starter will be isolated when in drive.

Thanks for your input.

[stidnam]

I haven't looked up the wiring diagrams specific to the 2007 Yaris, but disconnecting those wires will most likely result in the car not starting. I'll look up the circuit later, but if it's like the circuits I'm familiar with, the clutch switch closes to complete the circuit to power the starter relay. Simply joining the wires at the switch would allow activation of the starter relay without pushing the clutch in or being in Park/Neutral (Auto).

They've most likely done this as it was the easiest thing to do to complete the conversion. You'll probably find that the Park/Neutral position switch was just extra effort to run the wiring to that they avoided doing.

[stidnam]

Ok I've looked up the diagrams and it's as I described in my last post.

To further add to this, the Park/Neutral Position switch is on the front of the gearbox in the engine bay, which is probably why they didn't bother wiring it in - if done per the factory design, the wires for this switch would go through the fuse box on the right hand side of the engine bay.

The plug in question for the Park/Neutral position switch is C27 in the wiring diagram I have, and it looks like this. The pin coming from ST2 on the ignition barrel goes to pin 4 of this plug and pin 5 goes through a junction connector to the ST relay and the ECU STA pin.



It's worth noting that the signal comes into the bay through the CA2 (pin 10) fuse box connector and back out the CA1 fuse box connector (pin 9)




In saying all that, it's probably going to be easiest to run two new wires from the old clutch start wiring to the Park/Neutral position switch. This is all under the assumption that I'm correct and that someone has just done the dodgy per my original thinking.

Feel free to PM me if need be

[Paul Leonard]

Hi, Unsure, I do know all the wiring running to the transmission is there and in tact. I think when these cars are built, they put wiring in for different versions of the cars. I have a little Daihatsu mira that I installed A/C into, and, all the necessary wiring was in the car, I just needed to plug it in.

I had thoughts like you suggest running some extra wires if need be.

Yes, my diagram says the same thing, ca1 and ca2 are either side of the neutral start switch.

the diagram also suggests that there is a junction connector A25 where the power splits off going either to the neutral start switch or the clutch pedal switch. Then comes back to A25 through different pins

You suggest CA1 and CA2 are on the fuse box?

Just wondering where Junction connector A25 is?


Just found both connectors, they are the fuse box. Will work through it.

[stidnam]

I think you're on the right path there to check if the wiring is actually there from A25 through to the fuse box connection.

A25 is actually in the fuse box as well. In the bottom right hand side by the look of things, though hard to tell exactly. Looks like this



Edit: Actually, just thinking about it. If the wiring is all intact in the fuse box and that neutral start switch is wired correctly, and if they have joined the clutch switch wiring, then cutting it may actually work as the only way to create that circuit is through the Park/Neutral switch...provided it's all been wired correctly. It's bound to be easier to check that than perhaps pulling the fuse box apart.

[Paul Leonard]

Thanks again,

All fixed, I disconnected the two wires on the clutch pedal from one another, and it worked.

Now starts only in neutral and park.

Still have no idea why it was done. Maybe there may be a intermittent fault in the neutral start circuit and they just worked around it.

Will troubleshoot that if it happens.

First time I have had to take something out of a car to make it work

Penelope Pitstopped it.

Thanks again for everyones input.

[stidnam]

Glad to hear you got it sorted and good to hear that the wiring was all there and hooked up.

I'd speculate someone made an assumption that they needed to bridge the clutch switch to complete that circuit without actually testing if it was necessary.

[Paul Leonard]

I reckon your right