Check VSC 4LO and check engine, Road trip days away (1 Viewer)

[a200]

I started it just long enough to pull it inside and I noticed the 4lo light. I parked it for the night. Today nothing had changed and I tried to engage 4 low in the garage and then go back to 4 high. It is stuck in 4low. What should I do next.

UPDATE/EDIT:
Not stuck in 4 low
Just stuck in limp mode
Can clear codes to return to normal operation

OBD-IIOBD-II
DTCs: 1
----------------------------
P2440 [0x2440]
Secondary air injection (AIR) switching valve, bank 1 - valve stuck open
Status: Confirmed
============================
Engine control unit #1Engine control unit #1
DTCs: 1
----------------------------
P2440 [0x2440]
Secondary air injection (AIR) switching valve, bank 1 - valve stuck open
Status: Confirmed
============================
ABS control unit #2ABS control unit #2
DTCs: 2
----------------------------
C1201 [0x5201]
Engine Control System Malfunction (VCS lamp ON-RX3) or ECM/TCM malfunction / 51
Status: Confirmed

 

[isthatalexus]

Just to rule out captain obvious: shift to 4LO was done while stationary and shift lever in N, yes? (no intent to insult intelligence; I did not check your poasting history, so no idea if you are Level 19 Super Wizard or n00bish.)

If shift procedure was good, then it *could* be that your undercarriage wash was the straw that broke the camel's back inside the actuator housing, pushing an already existing corrosion/contact issue over the edge.

Have you pulled codes? (strong 'buy' rating on this as next step)

 

[tbisaacs]

Pull the code with an OBD II reader

 

[a200]

Just to rule out captain obvious: shift to 4LO was done while stationary and shift lever in N, yes? (no intent to insult intelligence; I did not check your poasting history, so no idea if you are Level 19 Super Wizard or n00bish.)

If shift procedure was good, then it *could* be that your undercarriage wash was the straw that broke the camel's back inside the actuator housing, pushing an already existing corrosion/contact issue over the edge.

Have you pulled codes? (strong 'buy' rating on this as next step)

I was in N.
I have only been here a couple years so feel free to cover the obvious.

I have a bluetooth obdii device on my truck. What android/linux software do you guys recommend to pull the codes?

 

[a200]

OBD-IIOBD-II
DTCs: 1
----------------------------
P2440 [0x2440]
Secondary air injection (AIR) switching valve, bank 1 - valve stuck open
Status: Confirmed
============================
Engine control unit #1Engine control unit #1
DTCs: 1
----------------------------
P2440 [0x2440]
Secondary air injection (AIR) switching valve, bank 1 - valve stuck open
Status: Confirmed
============================
ABS control unit #2ABS control unit #2
DTCs: 2
----------------------------
C1201 [0x5201]
Engine Control System Malfunction (VCS lamp ON-RX3) or ECM/TCM malfunction / 51
Status: Confirmed

 

[lx200inAR]

SAIS will trigger the 4WD/VSC stuff. If that tripped while you were in 4lo, you may be stuck in 4lo. Did you verify that you are actually in 4lo? I can't remember now if the 4lo light comes on with the SAIS code. I suspect the C1201 code is just in response to the first code.

 

[lx200inAR]

IN this thread, his 4lo light is on. I'd verify you are actually in 4lo.

'09 LX Check VSC System- Dash Lights & Trouble Codes

Recently had the "Check VSC System" message pop up on my dash along with a host of warning lights (traction, check engine, flashing 4LO, etc.). Battery was replaced in 2019 with a Lexus branded 8 yr. battery. I think it's still good...12.4 volts in acc mode and 13.6 volts after startup. Went...

forum.ih8mud.com

 

[a200]

IN this thread, his 4lo light is on. I'd verify you are actually in 4lo.

'09 LX Check VSC System- Dash Lights & Trouble Codes

Recently had the "Check VSC System" message pop up on my dash along with a host of warning lights (traction, check engine, flashing 4LO, etc.). Battery was replaced in 2019 with a Lexus branded 8 yr. battery. I think it's still good...12.4 volts in acc mode and 13.6 volts after startup. Went...

forum.ih8mud.com

I think I am probably stuck in limp mode.

 

[kcjaz]

Check the SAIS harness plugs and wires. Several here have had issues with wire insulation rubs causing a short though that is mostly associated with rigs that have installed an air compressor and used the Slee bracket.

 

[lx200inAR]

I think I am probably stuck in limp mode.

Wouldn’t be surprised. I can second the Hewitt gen 2 kit for bypass. It’s not cheap, but works better than others.

 

[a200]

Check the SAIS harness plugs and wires. Several here have had issues with wire insulation rubs causing a short though that is mostly associated with rigs that have installed an air compressor and used the Slee bracket.

I am all stock under the hood. I will take a look though.

Wouldn’t be surprised. I can second the Hewitt gen 2 kit for bypass. It’s not cheap, but works better than others.

Is that the kit you have on yours? I am going to reach out to them today. That seems like the fix though.

 

[lx200inAR]

I am all stock under the hood. I will take a look though.



Is that the kit you have on yours? I am going to reach out to them today. That seems like the fix though.

Yes. When I bought my truck it had a bypass installed already. It was a cheaper version that didn't do a great job. It worked when it was below 60 degrees, but if it was over that then every 2nd cold start I'd get a temperature sensor mismatch DTC that I'd have to clear. I finally bit the bullet and bought the Hewitt one this year. It cleared all my troubles, and I stopped getting the DTC. I'm definitely a proponent for removing SAIS completely and the Hewitt Gen2 kit lets you do that rather than having to leave all the parts in like the cheaper bypasses. The Gen 2 Kit basically just simulates an entirely functioning system. Whereas the cheaper ones try to fake the computer into thinking it doesn't need to run (at least that's what I think it does, I know they are completely different approaches to bypassing).

 

[isthatalexus]

If you are truly stuck in 4LO (not limp), put truck in N, turn truck off, disconnect battery, turn 4LO switch to HI, reconnect battery. I've seen this procedure surprise the truck out of the low box.

As far as Dx, I agree with poasters up-thread about checking for wire damage. A repeat offender for induction/exhaust issues is the harness that sits in the valley. Rodents like it there, they are as lazy as they are hungry, and the nourishing food wires are literally right there. A cheap snake camera comes in handy for this investigation.

Finally, in diagnostics, pulling codes is to MILs what binoculars are to a potato when it comes to bird watching. There exists only one copy of the MIL/CEL combination decoder manual, and it was last spotted by those guys that did the submarine adventure to the Titanic. (they weren't looking for the Titanic, they were looking for this sacred text, we were lied to. do not research this.)

 

[a200]

Alright I confirmed I was just in limp mode. My test drive through the yard and up the driveway felt like I was geared to high for low but obviously something was wrong so I jumped the gun on what I thought was happening.

I cleared the code and went for a drive. All was normal. I got it up to 50, shifted normal. What should my expectations be from here? What testing should I do now?

Thanks again for the help guys.

 

[TeCKis300]

Alright I confirmed I was just in limp mode. My test drive through the yard and up the driveway felt like I was geared to high for low but obviously something was wrong so I jumped the gun on what I thought was happening.

I cleared the code and went for a drive. All was normal. I got it up to 50, shifted normal. What should my expectations be from here? What testing should I do now?

Thanks again for the help guys.

I say you're good and enjoy the trip. Unless you're going to need low range.

Sounds to me like you had the typical 4LO actuator issue with the actuator and/or position sensors caught in a funny state. The reset fixed that. Keep the OBD device on hand for your trip. The other common root cause is some false emissions issue, aka MOAB CELs, due to elevation, or wide barametric pressure swings. It's not uncommon for these types of emissions CELs to affect actuation of low range either, as funny and unrelated as that seems.

The secondary air injection issue might be a coincidence but at least it's not the type of CEL that would prevent you from taking the trip. Again, keep that OBD device with you. If all else fails, pull the battery for a few minutes.

Take care of the issues after you get back.

This may help

Transfer Case Tuneup and Fix

Transfer case actuator issues are not uncommon on the 200-series. Not much documented solutions other than exercising the mechanisms regularly. Here's my attempt to provide more information on where and what the actuator is, how to service the transfer case actuator motor, and potentially...

forum.ih8mud.com

 

[lx200inAR]

The SAIS failure can trigger Limp mode. If clearing the code fixed it then count yourself lucky, but I’d expect it to come back. The SAIS codes are funny and trigger on different numbers of cold starts. As stated earlier, my temp failure only caused a DTC on every second cold start. When I put the new bypass in, it took 10 cold starts to fully clear “hidden DTC”. Pretty sure the SAIS system only runs during a cold start. Believe that’s why it’s so heavily tied to that occurrence.

 

[a200]

I say you're good and enjoy the trip. Unless you're going to need low range.

Sounds to me like you had the typical 4LO actuator issue with the actuator and/or position sensors caught in a funny state.

Transfer Case Tuneup and Fix

Transfer case actuator issues are not uncommon on the 200-series. Not much documented solutions other than exercising the mechanisms regularly. Here's my attempt to provide more information on where and what the actuator is, how to service the transfer case actuator motor, and potentially...

forum.ih8mud.com

I had the actuator replaced at the time of sale, so around 2 years ago now.

The SAIS failure can trigger Limp mode. If clearing the code fixed it then count yourself lucky, but I’d expect it to come back. The SAIS codes are funny and trigger on different numbers of cold starts. As stated earlier, my temp failure only caused a DTC on every second cold start. When I put the new bypass in, it took 10 cold starts to fully clear “hidden DTC”. Pretty sure the SAIS system only runs during a cold start. Believe that’s why it’s so heavily tied to that occurrence.

The lights came right back on about 30ft down the driveway this morning. IT sounds like damage to the sensors can happen if I keep driving it with these codes. Any thoughts on that? I think the 200 is setting this one out and I am just going to get the hewitt kit on order.

 

[lx200inAR]

The lights came right back on about 30ft down the driveway this morning. IT sounds like damage to the sensors can happen if I keep driving it with these codes. Any thoughts on that? I think the 200 is setting this one out and I am just going to get the hewitt kit on order.

(I'll caveat all this with the fact that I'm just a guy on the internet and have no professional wrenching creds, so take advice at your own risk)

I suspect you'd be okay for a couple days. It sounds like the biggest threat would be damaging the pressure sensor related to that bank. Assuming the actual problem is the valve being stuck open and not some other issue. With the gen 2 kit, the only part of the SAIS that still functions are the two pressures sensors (one for each bank). These can also be bypassed with add on parts from Hewitt (but are something like $250/sensor). I will say for me the hardest part of installing the gen 2 kit was getting the new kit plugs onto the existing sensors. They are between the intake manifold and the firewall and are not easily accessible and almost have to be switched out blind. I ended up removing the cowl to get more access (it still only took me maybe an hour from start to finish). I didn't have to install the block off plates as they were already installed from my previous kit.

I'll say, from the research I did back when I was figuring this out, it seemed like there were plenty of Tundra guys driving for months on this issue and clearing the codes every day. Usually, it was inspection time that was driving them to come up with a solution.

 

[grinchy]

On my rig if I forget to exercise the center diff and 4lo for a few months it will take five to seven attempts over a couple weeks to get both to engage and disengage without errors.

If you did get water into the actuator it will eventually evaporate and you can proceed to work it a bit until it works.

 

[a200]

(I'll caveat all this with the fact that I'm just a guy on the internet and have no professional wrenching creds, so take advice at your own risk)

I suspect you'd be okay for a couple days. It sounds like the biggest threat would be damaging the pressure sensor related to that bank. Assuming the actual problem is the valve being stuck open and not some other issue. With the gen 2 kit, the only part of the SAIS that still functions are the two pressures sensors (one for each bank). These can also be bypassed with add on parts from Hewitt (but are something like $250/sensor). I will say for me the hardest part of installing the gen 2 kit was getting the new kit plugs onto the existing sensors. They are between the intake manifold and the firewall and are not easily accessible and almost have to be switched out blind. I ended up removing the cowl to get more access (it still only took me maybe an hour from start to finish). I didn't have to install the block off plates as they were already installed from my previous kit.

I'll say, from the research I did back when I was figuring this out, it seemed like there were plenty of Tundra guys driving for months on this issue and clearing the codes every day. Usually, it was inspection time that was driving them to come up with a solution.

Thanks, I appreciate that. The reason I am throwing in the towel on taking the 200 is only because I have a good alternative adventure/tow vehicle in the form of a first gen tundra(on a side note I will be down near you at Maumelle Sun-Wed. You should drive though if you are close). So, did you have to bypass the pressure sensors too? I am hoping to to avoid that. I have the kit ordered. It will be here next week. I am digging through the other installs now.

Is this the part you found difficult? I am still trying to wrap my head around it.