ZRE152R cruise control not working

[Steve0]

Hello,

I have a ZRE152R Corolla sedan automatic that was purchased from a dealer on Parramatta Rd. no longer in business (of course). The dealer sold us a repairable write-off just before legislation changed, preventing the sale and registration of these cars.

Cruise control has never worked on the car. The Cruise light turns on, but pushing the stalk down to set the speed does nothing. I took it to a Toyota dealer, and they diagnosed the Inhibitor switch as open circuit, it has since been replaced but it has not solved the issue.

The car is an ex-manual that was somehow converted to an automatic, and I have a sneaking suspicion that this is the cause of my trouble with cruise control. I refuse to sell this car privately or trade it in at any dealer with a repairable WOVS status. I just want to make this car my own until its end of life.

Based on the fact that this car is an ex-manual, what might be missing from the car to get cruise control working? There are no error codes on the car.

Any help at all is much appreciated. Thank you.

Edited February 8, 2022 by Steve0

[Tony Prodigy]

Hi Stephen, let me say firstly that there's nothing wrong with purchasing a repairable write off as long as there was full disclosure and the damage to the structure was minimal. They usually write cars off because of the sum of the parts and high labour costs. Doesn't mean the car is no good. If a chassis rail was bent then it would've been classified differently I guess. My guess is that it had a front end collision, which is usually the most expensive type of accident you can have. Too many part there will add up quickly and with paint and labour this can quickly exceed the value of the car, so they just write them off.

Now the subject of your cruise control. I find it ridiculous that even after Toyota supposedly diagnosing what they thought was a faulty part, did they even bother to road test to see if it even worked ? From what you've said, they didn't because if they did, then you probably wouldn't be here asking the question. Did you take it back to them to query their diagnosis ? I'm not familiar with Corolla cruise control, hopefully others can chime in who have one, but there are items that need to be checked which could need the services of a trained technician.

Have a read of this article. It may help shed some light. I suspect the change over from a manual to auto may have something to do with it and there's probably an integral part missing in the transmission which needs to talk to the ECU. 

For the time being, you could check the basics like fuse and relay. It's possible they could've shorted something out during the smash repair.

Can you let us know what you find please ?

All the best mate 

 

[Hiro]

If it was originally a manual then there would have been a clutch switch that would disengage the cruise if you tried to change gear with it activated (otherwise the engine would free-rev).  Quite likely this was never removed (or was removed and wasn't bridged properly).

[Steve0]

On 2/9/2022 at 4:11 AM, Tony Prodigy said:

Hi Stephen, let me say firstly that there's nothing wrong with purchasing a repairable write off as long as there was full disclosure and the damage to the structure was minimal. They usually write cars off because of the sum of the parts and high labour costs. Doesn't mean the car is no good. If a chassis rail was bent then it would've been classified differently I guess. My guess is that it had a front end collision, which is usually the most expensive type of accident you can have. Too many part there will add up quickly and with paint and labour this can quickly exceed the value of the car, so they just write them off.

Now the subject of your cruise control. I find it ridiculous that even after Toyota supposedly diagnosing what they thought was a faulty part, did they even bother to road test to see if it even worked ? From what you've said, they didn't because if they did, then you probably wouldn't be here asking the question. Did you take it back to them to query their diagnosis ? I'm not familiar with Corolla cruise control, hopefully others can chime in who have one, but there are items that need to be checked which could need the services of a trained technician.

Have a read of this article. It may help shed some light. I suspect the change over from a manual to auto may have something to do with it and there's probably an integral part missing in the transmission which needs to talk to the ECU. 

For the time being, you could check the basics like fuse and relay. It's possible they could've shorted something out during the smash repair.

Can you let us know what you find please ?

All the best mate 

 

Hi Tony, thanks for the reply. Regarding the WOVS, we were not provided a WOVS report at the time of sale. I believe it was not legislated that used car dealers had to provide this report at the time of sale until around late 2010/11. I can confirm that it was a front end collision. Our local dealer found the front passenger airbag to be aftermarket on an inspection for the Takata recalls a few years back. They found the aftermarket airbag welded to the original Toyota airbag housing with two spot welds. The original wiring harness was also salvaged and joined to the aftermarket airbag by twisting the wires together and wrapping electrical tape around them. My friend is a mechanic and replaced it with a brand new genuine one to correct an intermittent airbag warning light. He also changed the inhibitor switch for me.

My Toyota dealer did the diagnostic work but did not replace the parts. Fuses and relays were checked and found to be in order. The only fault found was the inhibitor switch as open circuit. Thanks for the article, I will pass this on to my auto elec. as it may assist him in troubleshooting. I do agree that the manual > auto conversion was not done with cruise control in mind. Thanks for your help, and I will be sure to update the thread with the final outcome.
 

20 hours ago, Hiro said:

If it was originally a manual then there would have been a clutch switch that would disengage the cruise if you tried to change gear with it activated (otherwise the engine would free-rev).  Quite likely this was never removed (or was removed and wasn't bridged properly).

Thanks Ian. I can confirm that the car was indeed a manual before it was declared a repairable write-off. I'm seeing an auto electrician tomorrow to have some safety lights added to the car. Do you think it is worth having him tackle this job? If he needs to remove the clutch switch, what is involved with the "bridging" process? I want to try to point him on the right track if I can. Your help is greatly appreciated.

Edited February 9, 2022 by Steve0

[Hiro]

2 hours ago, Steve0 said:

Thanks Ian. I can confirm that the car was indeed a manual before it was declared a repairable write-off. I'm seeing an auto electrician tomorrow to have some safety lights added to the car. Do you think it is worth having him tackle this job? If he needs to remove the clutch switch, what is involved with the "bridging" process? I want to try to point him on the right track if I can. Your help is greatly appreciated.

It depends on what remaining electronics from the manual are in the car, and how the wiring works.  If the clutch switch is still present, then you need to work out what happens electrically when the switch is activated (which the clutch pedal would do when you aren't pressing on it) - it'll either be a normally-open switch (ie it gets "closed" when activated, allowing electricity to flow, in which case you need to "short" the two terminals together (essentially bypassing the switch entirely); or a normally-closed switch (the default state is closed and it gets held open by the pedal until you press it, this is how brake pedal switches work to turn your brake lights on.  Without the pedal there the switch is closed all the time and the cruise system is seeing a constant 'cancel' signal - in this case you need to unplug the switch (if it's there) and leave the body plug in place with nothing connected.  Bear in mind that manual cars probably used the clutch switch as a neutral start too (the follow-up generation ZRE182 does) where you have to press the clutch to be able to start the car, but if you have an auto ECU it might not be looking for that signal.

 

If the switch has been removed, there will most likely be an un-used plug above the left side of the driver's footwell.

[Steve0]

On 2/10/2022 at 8:57 AM, Hiro said:

It depends on what remaining electronics from the manual are in the car, and how the wiring works.  If the clutch switch is still present, then you need to work out what happens electrically when the switch is activated (which the clutch pedal would do when you aren't pressing on it) - it'll either be a normally-open switch (ie it gets "closed" when activated, allowing electricity to flow, in which case you need to "short" the two terminals together (essentially bypassing the switch entirely); or a normally-closed switch (the default state is closed and it gets held open by the pedal until you press it, this is how brake pedal switches work to turn your brake lights on.  Without the pedal there the switch is closed all the time and the cruise system is seeing a constant 'cancel' signal - in this case you need to unplug the switch (if it's there) and leave the body plug in place with nothing connected.  Bear in mind that manual cars probably used the clutch switch as a neutral start too (the follow-up generation ZRE182 does) where you have to press the clutch to be able to start the car, but if you have an auto ECU it might not be looking for that signal.

 

If the switch has been removed, there will most likely be an un-used plug above the left side of the driver's footwell.

Hi. The auto-elec that I was going to see is not able to look into this for me right now, so I've engaged another that actually installs aftermarket cruise control and knows his way around existing systems.

The plugs for where the clutch pedal was installed have been taped over with duct tape. I could not find the clutch pedal switch installed, however, there is a wire wrapped in conduit hanging down over that area. It has been snipped and just left hanging there. Black, green wire and another white and green wire, both wrapped in corrugated black conduit. There is a single wire running from the brake pedal, twisted together without solder, running over to the auto gearbox selector.

I assume that the cut wires are redundant if the ECM has been switched to an auto one. Or, am I getting mixed up with the ECU? I have no idea. haha.

I found a post from a member of the Whirlpool forum who got cruise working: https://whrl.pl/Reng1q. He has a manual Corolla, and he had to run two wires from the spiral assembly to the ECM in the engine bay for cruise to work. I wonder if I should do the same being that I'm working with a manual harness? I'm just not too sure what to do with the clutch switch wires if they were indeed those wires. Pressing on the brake cancels cruise on an auto, so do I need to bridge that wire that was added, running to the gearbox selector? It controls the unlocking of the gearbox selector when the brake is pressed down. Any help at all from anyone is much appreciated as I will pass it onto the tech.

Edited February 16, 2022 by Steve0

[Hiro]

The wire running from the brake pedal to the selector will probably be for the shift interlock, which stops you from being able to move the transmission out of PARK without pressing the brake pedal (obviously not needed on an auto).

 

I'm almost certain that your problem will lie with the wires that have been cut up above where the clutch pedal used to live (or the plugs that have been taped over), not with the brake pedal (as pressing the brake on a manual cuts cruise-control off too, so that shouldn't have changed).  Unfortunately I don't have a wiring diagram to confirm.