Estimated reading time: 5 minutes.
I am writing this article to hopefully save Toyota Landcruiser owners thousands of dollars, even tens of thousands of dollars that could potentially end up being wasted on their 200 Series Toyota Landcruiser for misdiagnosed transmission issues.
I have seen it all too common on forums that owners of the VDJ200 Series Toyota Landcruiser seeking help and assistance regarding a 5th and 6th gear lock out, and if you’re reading this, it’s probably you right now.
Let’s start with the most relieving fact of all – it’s not your transmission. It’s a hidden limp mode triggered inside the ECU relating to an EGR fault, an incorrectly recalibrated ECU when an EGR has been modified or removed entirely, or it’s relating to an over boost or under boost condition produced by the turbocharger system and it’s accessories such as hoses, intercooler or filters.
It is common in the past that ECU and engine tuning workshops simply turn off the DTC (diagnostic trouble code) relating to any ’04XX’ code inside the ECU when blocking the EGR. These ’04XX’ codes all relate to the function of the EGR system, and will give a check engine light if a malfunction or fault is detected. When tuners disable these DTC codes, they are essentially disabling the features of the code such as reduced power, limp mode and a check engine light. In this particular generation of Denso ECU, there is various stages of limp mode and DTC’s. When turning off the codes only, other features of the DTC’s may still be embedded into other parts of the operating system inside the ECU.
With the DTC’s ‘turned off’, you are now experiencing a limp mode that relates to them, but part of the DTC feature (a check engine light) has been disabled alongside the other codes that have been deactivated as part of your EGR blank or removal. Therefore, everyday logic would dictate that it appears to be an unrelated mechanical issue relating to the transmission itself, not detectable by the ECU’s DTC’s, plus, you had the EGR ‘deleted’… so, how could it be that? This logic is unfortunately not correct in this scenario.
This problem arrives in multiple ways, and let’s look at some common scenario’s below:
Scenario A)
You have owned your car for 200,000km’s and finally figured it would be the time to do injectors, an intake clean and polish it all off with a engine and transmission tune.
You drive away, spend 3-6 months driving around town before it’s finally time to hook the van up and go away for the weekend. You hit the highway for the first time in a long time with the van, and suddenly you realise it’s locked you out of 5th and 6th gear.
But, good news, this actually DOES have a check engine light coming up on the dash, and it’s P0299. This indicates a turbo underboost or overboost condition.
Solution or Fault
Start by checking the hoses behind the back of your intercooler to your MAP sensor, it is common for these to blow off, even more so after a tune has been done as your Toyota Landcruiser 200 Series is likely running a fair bit more turbocharger boost than it used to.
If these hoses are all connected to their pressure source, both sides of the filter, and the sensor, check for cracks or splits in the MAP filter as seen below. To prevent this from ever happening again, we offer a barbed stainless steel MAP filter replacement.
The position of this MAP filter and sensor is in this area behind the intercooler as seen below. It may need to come off for you to access it easily.
If BOTH of these are all ok, there is a chance you may have a cracked intercooler. The earlier the year model of 200 Series you have, the more likely this is to have occurred. Check for oil weapage around the end tanks, and near the hoses connecting to it.
This P0299 code indicates a genuine turbo under boost or over boost fault, where essentially the ECU is requesting a certain amount of boost that the vehicle isn’t producing leaving a significant ‘boost deviation’ between actual and target, and the ECU’s logic detect’s this as an underperformance.
The reason this has finally occurred now after all this time is because you have introduced a larger amount of load to the vehicle, changing the areas in the map where it operates to sustain this much weight, or how much constant pressure the turbochargers are now producing.
The issues listed above could have always been pre-existing, they may have occurred since the day it was tuned, or it could just be bad timing where finally this extra load popped one of those MAP sensor hoses off the sensor or the filter.
In a worst case scenario, your 200 Series has an actual turbocharger fault and will require 2 x new Genuine IHI replacement units.
Scenario B)
You have owned your car for 10,000km’s and part of the preparation for your planned usage was to do an intake clean, disable the EGR system and give a engine tune on the dyno. There was no fault with the car prior.
You drive away from your chosen workshop, happy as possible, car goes great, everything’s going well. Within 2-3 days, you’re on the highway and you notice it’s locked you out of 5th and 6th gear. There are no faults on the dash to indicate what could be going on.
Solution or Fault
A fault this recent to the work being carried out usually indicates that the tuning shop may have turned off the codes, even fitted a blanking plate or delete, but haven’t disabled all the EGR valve maps relating to the solenoid’s function. The car attempted to cycle the valve, it dedicated no flow due to the blank that is now fitted, (usually happens at idle), therefore enabled that ‘hidden’ limp mode feature which may now lead you down a path to assume you have a transmission fault.
My advice here is to return to the shop that has carried out this work, and have them recheck the work. It may not necessarily be their fault ENTIRELY just yet, as there are other scenario’s where the EGR pipes behind the EGR cooler at the back of the cylinder head also crack and break.
While they have done the minimum required to disable the EGR system, your car may have an actual fault which is now more detectable than it previously was due to the recent modifications. It is NOT common place for workshops to entirely remove all limp mode functions while the EGR cooler, and valves are still physically place and plugged in, and this is a bit of a grey area as it could be there tuning, or it could be an actual fault of your car.
Scenario C)
You have owned your car for years, done around 50,000km’s+, had it tuned a long time ago, now suddenly your car is locked out of 5th and 6th gear on the highway.
This is the likely case that whoever did your tune some time ago, did a perfectly good job. However, some time has passed and one of your EGR valves has cycled it’s usual procedure (even ‘turned off’ there are still maps that will activate this valve if not all 100% disabled, not a big deal if the car has no faults) except this time something has gotten stuck under it, and it has not been able to close 100% of the way back down.
And there it is, you’re now locked out of 6th gear. So, what happens next?
Solution or Fault
II would again, start by returning back to the workshop who did the tune, have them revert the car to standard, have it perform the fault which will prompt the DTC (as it is no longer disabled in the tune), isolate the problem to confirm what has occurred, and then if you wish to still run a disabled EGR system, have them remove the cooler and valves entirely, or blank the EGR system ‘further down the line’ such as at the cylinder head, and leave the EGR valve’s unplugged so you know they will no longer ever try to operate again. Otherwise, they will have to actually physically fix the faulty EGR component, such as the valve, re-fit it, and put your old tune back in and hope it doesn’t do it again one day.
Modern disabling of the EGR system on a 200 Series Toyota Landcruiser allows for the complete removal of the EGR valves and cooler, with blank off plates being able to be fitted directly to the ports on the cylinder head if you wish to do so. Once this is done, it is now safe to remove the 5th and 6th gear lock out limp mode, as no faults relating to this system can occur.
The tricky part here is not all workshops are capable of this level of ECU calibration and will depend on who they work with to provide a solid solution here.
The key take away here is if your transmission has locked you out of 5th and 6th gear in your 200 Series Toyota Landcruiser, IT IS NOT A TRANSMISSION FAULT. It is a limp mode function relating to the engine over boost/under boost or EGR function.
