D40 2.5D Auto (Spanish) Limp mode and more...

[Old.Tony]

I'm not sure if you wrote that or Stephen King did, but it sure sounds like a script for a horror movie!

The A/C switch will only affect the air con. Undoing an electrical connection should not have been able to release any gas (or fuel or oil or coolant). The sensors are secured to the vehicle and the electrical connection is then made. Sounds like your A/C had a fault, but the car will drive without it.

I know the SCV electrical connector comes off - I have my old SCV still, and it's just a typical connector like many others - the small tab that, when pressed, disengages the little plastic lip and allows the plug to come out.

It might be worth stopping with the electrical connections at this point, because you haven't indicated if the erratic "won't move in reverse" issue has gone away.

The other issue - the "ghost limp mode" - might very well be the SCV. That's worth trying some injector cleaner in now, and see if the problem reduces (it may not go away if the SCV is damaged). You also need to check if boost levels are "normal". Either problem could give you the false limp modes and poor fuel economy. Checking boost levels first would be less expensive (a BT OBD-II adapter on eBay is like $5 or so, good injector cleaner is about $18).

 

[patchyfog]

I'm not sure if you wrote that or Stephen King did, but it sure sounds like a script for a horror movie!

The A/C switch will only affect the air con. Undoing an electrical connection should not have been able to release any gas (or fuel or oil or coolant). The sensors are secured to the vehicle and the electrical connection is then made. Sounds like your A/C had a fault, but the car will drive without it.

I know the SCV electrical connector comes off - I have my old SCV still, and it's just a typical connector like many others - the small tab that, when pressed, disengages the little plastic lip and allows the plug to come out.

It might be worth stopping with the electrical connections at this point, because you haven't indicated if the erratic "won't move in reverse" issue has gone away.

The other issue - the "ghost limp mode" - might very well be the SCV. That's worth trying some injector cleaner in now, and see if the problem reduces (it may not go away if the SCV is damaged). You also need to check if boost levels are "normal". Either problem could give you the false limp modes and poor fuel economy. Checking boost levels first would be less expensive (a BT OBD-II adapter on eBay is like $5 or so, good injector cleaner is about $18).

Hi Tony. Maybe I didn't explain that very well. It wasn't the connector of the AC pressure switch that broke, it was that the plastic part came away from the metal threaded part (see picture). It was when I unscrewed this threaded part that I got covered in lovely cooling gas. I've ordered a replacement, hopefully it's the correct one, it seems the part number has been superseded a few times. How does one go about replacing this pressure switch/sensor without losing all the gas?

I have no doubt that the SCV connector will come off, I'm just wary at this point to use too much force in case it causes more damage. It feels as though a lot of the plastic stuff is quite brittle, on the driver's side at least. A new Denso SCV has been ordered for about $80, at close to 300k km it feels as if there is a good chance it will need changing anyway. If not then I'll keep it for the future.

The reverse limp mode hasn't occurred again...yet! I've reconnected everything, aside from the damaged AC switch/sensor, and will be taking it out for a drive tomorrow. I'll hook up my BT OBD-II connector to Torque and see what it says. I'll grab some injector cleaner while I'm out - is there one that you guys recommend over others or is it all a much of a muchness?

Thanks

https://www.dropbox.com/s/ag36f7svpgdi8kc/2020-05-02%2010.58.39.jpg?dl=0

 

[Tms40]

HI mate. Sorry to hear all your problems. I had limp mode trouble and it was as simple as having a bad connection/blown brake light. Brake light issues on the Navs are known to cause limp mode issues. Have you got an electronic brake controller? Mine was playing up and caused limp mode. I had to disconnect mine. Maybe it could be something so simple. Other that checking that I've got nothing

 

[patchyfog]

HI mate. Sorry to hear all your problems. I had limp mode trouble and it was as simple as having a bad connection/blown brake light. Brake light issues on the Navs are known to cause limp mode issues. Have you got an electronic brake controller? Mine was playing up and caused limp mode. I had to disconnect mine. Maybe it could be something so simple. Other that checking that I've got nothing

Hi mate, I actually do have an electronic brake controller fitted. It was already on the vehicle when I purchased it but honestly, I can't ever really imagine needing it. I don't have a boat, a campervan or a car trailer. How would I go about disconnecting it? It is straight forward?
When I think about it, I'm pretty certain limp mode has only ever occurred immediately or very shortly after the brake pedal has been depressed, either lightly to slow the vehicle or hard to pull it up completely.

Took it for a quick spin this morning: on the initial start, it wouldn't move; engine off then on, it moved; changed gear (auto) and again wouldn't go; engine off then on, travelled about 30m to a junction at which point I hit the brakes; went to accelerate, revs to about 2k but no movement; engine off then on, no more issues for the following 5k drive.

Checked for fault codes but there were none. I logged the trip in Torque Pro...but being a bit of a dimwit, I hadn't realised that the default setting only read GPS/trip. Now I've changed that, it should record everything that the ECU/OBD-II will allow and I'll have to take it for another run. Is there someone on here that knows how to read/decipher the results? Presumably, it will just be a bunch of numbers that will mean nothing to me.

Thanks for the advice

 

[ericcs]

what brand and type of brake controller is it, maybe you can unplug it's harness from the unit to eliminate it!

 

[Old.Tony]

I have used Liqui Moly Fuel System Cleaner in the past with success, and put another bottle in the tank yesterday.

 

[patchyfog]

what brand and type of brake controller is it, maybe you can unplug it's harness from the unit to eliminate it!

Hi ericcs. It's a Tekonsha Primus IQ. After a quick Google, these look like a plug and play device - is that right? Whereabouts do they plug into the vehicle?



Hi, Tony. I ended up using "Nulon Diesel Fuel System Extreme Clean" as it had good reviews on Supercheap. I've barely run it through yet though as I still have no real cause to drive anywhere other than the dog park.

 

[ericcs]

it's only plug n play if the car has a brake control harness fitted. I haven't heard of the d40 having this feature, so, otherwise it's a standard method of install.

 

[patchyfog]

it's only plug n play if the car has a brake control harness fitted. I haven't heard of the d40 having this feature, so, otherwise it's a standard method of install.

Okay, thanks. So, will I need to completely uninstall the unit or can I just disconnect the power supply at the battery, leaving everything else in situ? By everything else, I mean the connection to brake light switch/pedal and trailer connection. There's always the possibility that I or someone using the ute will need it further down the track.

 

[bods]

You can just unplug the unit from the vehicle. It will have a black 4 pin connector on the back of it. That way you know it is completely isolated from the braking circuit in the car. It won't affect the brake light functions if you simply unplug it.

 

[ericcs]

Okay, thanks. So, will I need to completely uninstall the unit or can I just disconnect the power supply at the battery, leaving everything else in situ? By everything else, I mean the connection to brake light switch/pedal and trailer connection. There's always the possibility that I or someone using the ute will need it further down the track.

As Bods said, you can just unplug it and remove the unit, then plug it back if you need it again. otherwise, if you don't want it, i might be interested in buying it off you, as i will be needing one for my d40 in the coming weeks!

 

[patchyfog]

You can just unplug the unit from the vehicle. It will have a black 4 pin connector on the back of it. That way you know it is completely isolated from the braking circuit in the car. It won't affect the brake light functions if you simply unplug it.

Hey bods, okay, thanks. Not sure if you saw the earlier post which has led me to disconnecting the brake controller or not but, Tms40 has suggested that is possibly the cause of my limp mode. If the brake controller is actually what's causing the issues, do you believe that just unplugging the connector would change anything?
I mean, it's an easy enough thing to check I suppose.

Thanks for the advice

 

[patchyfog]

As Bods said, you can just unplug it and remove the unit, then plug it back if you need it again. otherwise, if you don't want it, i might be interested in buying it off you, as i will be needing one for my d40 in the coming weeks!

If I completely remove it then I'll let you know mate.

 

[ericcs]

If I completely remove it then I'll let you know mate.

thanks!

 

[bods]

Hey bods, okay, thanks. Not sure if you saw the earlier post which has led me to disconnecting the brake controller or not but, Tms40 has suggested that is possibly the cause of my limp mode. If the brake controller is actually what's causing the issues, do you believe that just unplugging the connector would change anything?

I mean, it's an easy enough thing to check I suppose.



Thanks for the advice

I'd be unplugging the plug from the actual controller rather that just removing the wire from the battery. The reason being, the controller is still wired to the brake light circuit and could be causing feedback issues onto this circuit, unplugging it completely removes any risk of it creating any interference...

 

[ericcs]

yep, just unplug at the back of the controller

 

[patchyfog]

Okay, so just a quick update. I unplugged the brake controller (connector on rear) and have had no issues since. Hopefully I haven't spoken too soon but after 6 trips, albeit short ones, I'm feeling fairly confident.

Thanks for all the help, guys. It's very much appreciated.

 

[bods]

Okay, so just a quick update. I unplugged the brake controller (connector on rear) and have had no issues since. Hopefully I haven't spoken too soon but after 6 trips, albeit short ones, I'm feeling fairly confident.

Thanks for all the help, guys. It's very much appreciated.

What you will find is that I'd you're driving and you put your left foot on the brake, just enough to put on the brake lights, but not enough to slow down, the engine computer will cut power as it thinks you are braking.

Your brake controller may be playing up and sending a false signal back on the brake light wire that it uses to sense when you have your foot on the brake, as it will use this wire to put the brake lights on when you use the manual boost button on the controller. I'd say the engine computer is seeing this as you putting your foot on the brake, hence reducing engine power.

I believe all d40s are like this. The earlier d22s aren't, but they must have a brake light circuit in the engine computer as the later models do it. (I only know this because I have a 2010 which didn't do it stock, but after changing the ecu to one from a 2014 model that had been remapped it now does it).

I should also say, good to hear it was a simple fix.

 

[ericcs]

Okay, so just a quick update. I unplugged the brake controller (connector on rear) and have had no issues since. Hopefully I haven't spoken too soon but after 6 trips, albeit short ones, I'm feeling fairly confident.

Thanks for all the help, guys. It's very much appreciated.

my son's car(2010 BT50) had similar symptoms, was the after market cruise control module. seems maybe like after market add on's are the first go to when problem hunting!

 

[patchyfog]

Thanks, @bods and @ericcs

Well, it appears I spoke too soon. After about 7 or 8 trips and no issues with the electronic brake controller disconnected, I decided to stop logging OBDII data and go back to using my Bluetooth for something else - 2 or 3 trips in and "limp mode" is back!

The first reoccurrence was after initial start-up, then later during the same trip, about 50 meters after being stopped at the lights it came back. Luckily there was somewhere to pull over.
Then today I turned on the ignition and it sounded as if it was struggling, put it into reverse and it cut out. Couple more goes and it did the same thing. Revved it to about 2-3k in PARK, released the accelerator and then knocked it into reverse. It started moving and then limp mode was back. 2 minutes up the road and the engine light came on (P0093 - large fuel leak). Wiped fault codes and set off again - no further issues...though I was only driving for 10-15 minutes all up. This time I logged the journey.

Does anyone on here have any experience reading this logged data? I pretty much set it to log everything that it would allow but I have no idea what I'm looking at.