Dash Has Come Up With 3 Warning Messages (Heeelp!)

[Smiler AS]

Scan thingy said P0400.

Sticky EGR

The P0400 code only came up briefly. Not since it all started.

Cleaned the valve tonight, wouldnt have said overly bad. 3 holes from the manifold all clear.

Took off the motor off the valve too, tested spring, could move valve with very little effort required, pinky touch.

All back together, drove off, up to about 20mph and up the warnings pop again.

Checked codes ABS 33, VSC had one but cant remember it now. doh! and 4wd 96.

These seem to be related to the rear ABS.

Could be on to the ABS / speed sensor now, I can understand why it would cancel VSC and 4wd without getting good speed/ABS signal.

Frustration.

Back to square one, maybe not, just slowly ticking each possibility off one at time.

[shcm]

There's a test mode for sensors, if you want to risk trying it. PDF attached.

Think there's a mis-print. When it says pin 14, I think it means pin 4.

Diagram of sensor on wheel mounting below. It would appear the first connector for the sensor, is behind the boot side panel trim, if it needs to be changed.

VSCCheckMode.pdf

[Smiler AS]

Weather too bad to check the sensor, ive given up and booked into local Toyota Dealer, guy didnt sound overly surprised by the warning lights, more of a casual comment, "it will the diesel model is it?". They are closed tonight and cant get car in until Tue 11th. At least its booked in now.

Sounds like he has been there before.

Suppose one of the reasons got the car from a Toyota dealer was the warranty on it.

Today,

The usual rear ABS codes (33, 38) are coming up once I set off.

However,"Check VSC" is coming up with codes VSC 36 & VSC 39 as soon as I start up now. What are they?

(quick search on google says something about zero point calibration - wonder if I undone this calibration when changing batteries and/or trying to erase the PS codes). But, il let the Pro's let me know if thats right.

[Seth1]

Smiler keep us posted, my car is out of warranty so it would be good to be aware of what eventually fixes this problem, have a good Christmas

[Smiler AS]

Will do bud. Yeh, im in a years Toyota Approved Warranty and booklet says anything ABS related is covered plus emissions too.

So between ABS sensors and possibly EGR valves, should have it covered.

[Smiler AS]

Typical. The Rav must have heard me about going in to dealer for a check up.

Not the usual VSC, 4x4 warnings today but...

twice, once at a roundabout and once turning into a junction the warning "high oil temperature in transfer case" pops up, then "2wd" but then once cruising back along the road ( 20 - 30 seconds later) all is fine again. Even the warning triangle is off. The roundabout and junctions are literally 5mins from house.

Seth1, I believe you mentioned you had this warning briefly too, so I find it hard to believe we both have a rear faulty ABS sensor AND poor/low oil in our transfer cases.

Reading up on the warning links to the DTC C1299 "Cancellation of 4WD" and although "high temp transfer case oil" can cause it there are other symptoms, one is the 4wd ECU being not happy, and obviously it aint going to be happy if dodgy ABS signal (even briefly).

Im beginning to wonder if the rear right ABS electrical connector socket itself is dirty/damp etc., possibly loosing connection as Rav is cornering throwing up the DTC and going into 2wd for 30 sec then once back on the straights its getting a constant signal from the ABS, its then fine and 4wd all back to normal.

And no, im not taking the roundabouts sideways / rally style!!!

Schm, you mentioned the first connector for the rear wheel sensor is behind the boot side panel trim, just making sure that means I can access that connector from inside the boot, removing the interior side panel?

Anyone any info on how to remove the inside boot side panel properly?

[anchorman]

Have a look at pages 25 & 26 here;

http://www.toyota-tech.eu/legacy/Toy/aimuploads/%7B4FA27C4E-37F8-516C-B5DC-4A39A3FE37F8%7D/Detachable%20towing%20hitch%20PZ408-X0561-00%20AIM%20000%20463-9.pdf

[Smiler AS]

Spot on, ta very much.

[Seth1]

Weather too bad to check the sensor, ive given up and booked into local Toyota Dealer, guy didnt sound overly surprised by the warning lights, more of a casual comment, "it will the diesel model is it?". They are closed tonight and cant get car in until Tue 11th. At least its booked in now.

Sounds like he has been there before.

Suppose one of the reasons got the car from a Toyota dealer was the warranty on it.

Today,

The usual rear ABS codes (33, 38) are coming up once I set off.

However,"Check VSC" is coming up with codes VSC 36 & VSC 39 as soon as I start up now. What are they?

(quick search on google says something about zero point calibration - wonder if I undone this calibration when changing batteries and/or trying to erase the PS codes). But, il let the Pro's let me know if thats right.

Smiler - I hope it all goes OK at the Garage today...can't wait to see what they come back with as the route cause of the dash error codes....

Keep me informed please!

Cheers!

[Smiler AS]

Went along this morning but ended up cancelling the appointment im afraid.

Havent had any warning lights in about a fortnight now (since the thaw).

I still went to garage and actually told him the code numbers I had, but no point doing much more until comes back.

The guy was good and diagnosed it as the ABS sensor being dirty as they have had two in recently, they just needed taken out and cleaned up.

Im gathering whatever crap / dirt was frozen on to the tip of the sensor has now thawed off.

ABS on first then quickly followed by car disabling VSC and 4WD as the ABS sensor is also a speed sensor for the ECU to work out VSC and 4WD control.

Said I had the odd "high heat oil transfer case" warning, he correctly commented that this was just prior to the above warnings coming on, this was due to the sensor not recording a speed signal from one of the rear wheels (as opposed to an ABS signal (until braking)) and disabling 4wd as a (over cautious) means of protection.

Yes, im glad thats all it was but then disabling 4wd is a bit of pain (especially at the time of the deep snow), but then I suppose its a 4wd system that relies on a lot of sensors etc.

Simply taking out the sensor and giving it a clean with electrical cleaner is good solution.

If I recall you had codes 33/38 too, so could be same sensor. As diagrams above, easy to to do, jack up, wheel off, and was either a 8/10mm socket.

PS. Halfords have a good 3 ton 4x4 good lift height jack at half price at moment.

____

The VSC calibration codes (36, 39) I didnt mention, as that was me with the jumper wire and didnt complete procedure to calibrate the Yaw Sensor, solved/ done that myself before going to dealer by going through the zero point calibration procedure.

____

Thank you all though, I believe schm had the correct diagnostic at "just crud on the sensor" earlier.

Just something il keep an eye an and can clean quite easily.

[shcm]

Thank you all though, I believe schm had the correct diagnostic at "just crud on the sensor" earlier.

Just for info:

I expect most modern systems have changed over to hall-effect sensors, but, when I was working on ABS/VSC last (about 8 years ago), there were 2 types of sensors we catered for.

VR - Variable Reluctance (a bit like me getting out of bed). The same as VR sensors used for engine speed detection. Cheap and fairly robust, but some interesting conditioning circuits needed to produce a stable square wave from the signal they produce. They don't work down to zero speed though.

Hall Effect. - Usually a nice "clean" output signal, but they need to be supplied with power unlike the VR. Probably less "robust" than the VR (although things move on and improve). They do work down to zero speed though. The RAV almost certainly has some incarnation of these, because it can do stuff like hill start assist.

[Smiler AS]

The guy at dealership did come away with something in somewhat more basic terms.

The sensors do a check that they are present on startup, they do a low speed check, think it was above 19mph (explains why i didnt get get warning until out on main road with the bad weather ie, didnt get above 19mph until main road some days). Also a high speed check is done but only up to 50mph.

Anything above 50mph, the sensors are "used" more as a speed sensor, hence the 2wd drive only warning would come up first followed by ABS warning when I reduced speed.

Whether it was right or not, dont know but sounded convincing enough. Plus he said just to call if the warnings appeared again.

[Seth1]

Went along this morning but ended up cancelling the appointment im afraid.

Havent had any warning lights in about a fortnight now (since the thaw).

I still went to garage and actually told him the code numbers I had, but no point doing much more until comes back.

The guy was good and diagnosed it as the ABS sensor being dirty as they have had two in recently, they just needed taken out and cleaned up.

Im gathering whatever crap / dirt was frozen on to the tip of the sensor has now thawed off.

ABS on first then quickly followed by car disabling VSC and 4WD as the ABS sensor is also a speed sensor for the ECU to work out VSC and 4WD control.

Said I had the odd "high heat oil transfer case" warning, he correctly commented that this was just prior to the above warnings coming on, this was due to the sensor not recording a speed signal from one of the rear wheels (as opposed to an ABS signal (until braking)) and disabling 4wd as a (over cautious) means of protection.

Yes, im glad thats all it was but then disabling 4wd is a bit of pain (especially at the time of the deep snow), but then I suppose its a 4wd system that relies on a lot of sensors etc.

Simply taking out the sensor and giving it a clean with electrical cleaner is good solution.

If I recall you had codes 33/38 too, so could be same sensor. As diagrams above, easy to to do, jack up, wheel off, and was either a 8/10mm socket.

PS. Halfords have a good 3 ton 4x4 good lift height jack at half price at moment.

____

The VSC calibration codes (36, 39) I didnt mention, as that was me with the jumper wire and didnt complete procedure to calibrate the Yaw Sensor, solved/ done that myself before going to dealer by going through the zero point calibration procedure.

____

Thank you all though, I believe schm had the correct diagnostic at "just crud on the sensor" earlier.

Just something il keep an eye an and can clean quite easily.

Smiler - will take it off and clean the sensor on Sat....Fingers crossed....

Codes are the same as yours....Only difference is that mine has never gone off on it's own....

About a week ago I thought I would clear the codes down...as soon as I moved they came back....lets see what happens...

Big thank you to all the contributers to this Forum.....

[Smiler AS]

Are the codes coming up as soon as you start up or move off, or moving above 19mph?

Mine got less and less and would only come on for a few mins then clear again to the point they havent returned at all.

We still have had a few good frosty sub-zero temp mornings but still nothing.

[Seth1]

Are the codes coming up as soon as you start up or move off, or moving above 19mph?

Mine got less and less and would only come on for a few mins then clear again to the point they havent returned at all.

We still have had a few good frosty sub-zero temp mornings but still nothing.

They dont come on while stationary, they come on as soon as I move - to me this indicates the ABS Sensor (I hope)!!!

[Smiler AS]

Yeh, that does sound better.

So connection is okay if no light when starting up when it does its self check thing.

Its when it actually comes to reading the speed / using the sensor the warning lights come on.

Note to self, dont park in deep snow.

[Seth1]

Yeh, that does sound better.

So connection is okay if no light when starting up when it does its self check thing.

Its when it actually comes to reading the speed / using the sensor the warning lights come on.

Note to self, dont park in deep snow.

I will give you some feedback over the weekend - As I remember its the Driver Side rear wheel...I just clean the sensor and replace, see what happens - I think I will disconnect the Battery...use that technique to clear the errors....

Question - Is there only 1 abs sensor or does each wheel have one???

[anchorman]

Every wheel. There is a nice diagram in section 4 here;

Brake layout.pdf

[shcm]

Just bear in mind there is some for of reluctor ring involved as well. This moving past the sensor, generates (in the case of hall effect sensors) the square wave output. The ABS/VSC algorithms rely on that signal being high integrity (or so the systems/software people have told me in the past, when they've ask for very challenging electronic hardware requirements :) ). If the ECU detects anything wrong with that, it will chuck a fault. So, a damaged reluctor can give the appearance of a faulty sensor.

Disconnecting the Battery may well clear a fault light, but I am not convinced it actually clears out all faults. All but the simplest ECUs I've worked on (20+ years) have had some form of non-volatile memory.

Just remember, If the ECU is replaced under warranty, the vehicle manufacturer will send it back to the component supplier for diagnosis and to potentially claim back cash. In order to validate that it is a genuine faulty unit, the supplier likes to be able to see what the claimed fault was. The paperwork is not always accurate, but the fault codes can help trace the problem. To get the unit to the supplier, the ECU has to be disconnected from the car Battery! With only volatile memory, those useful fault codes would evaporate.

[Seth1]

Just bear in mind there is some for of reluctor ring involved as well. This moving past the sensor, generates (in the case of hall effect sensors) the square wave output. The ABS/VSC algorithms rely on that signal being high integrity (or so the systems/software people have told me in the past, when they've ask for very challenging electronic hardware requirements :) ). If the ECU detects anything wrong with that, it will chuck a fault. So, a damaged reluctor can give the appearance of a faulty sensor.

Disconnecting the battery may well clear a fault light, but I am not convinced it actually clears out all faults. All but the simplest ECUs I've worked on (20+ years) have had some form of non-volatile memory.

Just remember, If the ECU is replaced under warranty, the vehicle manufacturer will send it back to the component supplier for diagnosis and to potentially claim back cash. In order to validate that it is a genuine faulty unit, the supplier likes to be able to see what the claimed fault was. The paperwork is not always accurate, but the fault codes can help trace the problem. To get the unit to the supplier, the ECU has to be disconnected from the car battery! With only volatile memory, those useful fault codes would evaporate.

Thanks for the information shcm and anchorman....I will clear the codes out using shorting pins 4 and 13 as described earlier....As my codes are the same as Smilers I will clean the rear right sensor and see what happens...

Will feedback over the weekend...

[Seth1]

OK - Took wheel off - took ABS sensor out - IT looked clean, cleaned it anyway, replaced and codes still there....

Shorted out PINs 4 and 13 - still getting ABS 33

Tried to clear the codes with pressing brake pedal 8 times within 5 secods or less - Tried several times and they would not clear at all...Diconnected the Battery for 20 mins - still the same....

Appart from booking it in at Westlands - any suggestions....(especialy why I can't now clear the errors??)

[shcm]

For DTC 33, it is shown as being generated when one of following conditions is met:

1. At vehicle speed of 10 km/h (6 mph) or more, open or short in sensor signal circuit continues for 1 second or more.

2. Momentary interruption of sensor signal from abnormal wheel occurs 255 times or more.

3. Open in speed sensor signal circuit continues for 0.5 seconds or more.

4. With IG1 terminal voltage 9.5 V or more, sensor power supply voltage decreases for 0.5 seconds or more.

and potential areas to look in:

Rear speed sensor

Rear speed sensor circuit

Sensor installation

Foreign matter on sensor rotor

Most of those are probably not going to throw up the DTC, without you moving, but it's possible that it can detect problems with the sensor (power supply open circuit and no current being drawn by the sensor from the ECU), without the wheels moving.

I'm sure you are doing this, but just to confirm, the brake pedal pressing for DTC cancellation has to be done with the thing still in diagnostic mode, i.e. with the wire between pins 13 and 4. It's worked for me no problem.

Also, to confirm, for the VSC/ABS ECU the info from techdoc states:

"Clearing the DTCs cannot be performed by removing the Battery cable or ECU-IG1 fuse"

If it is a connection/power supply type fault and it can detect it, it not unreasonable for the DTC not to clear. It probably is clearing, but coming back almost instantly.

Sorry, not much help, but I always find diagnosis "by remote control" a bit of a "challenge" at times. Much easier to actually be there

[Seth1]

For DTC 33, it is shown as being generated when one of following conditions is met:

1. At vehicle speed of 10 km/h (6 mph) or more, open or short in sensor signal circuit continues for 1 second or more.

2. Momentary interruption of sensor signal from abnormal wheel occurs 255 times or more.

3. Open in speed sensor signal circuit continues for 0.5 seconds or more.

4. With IG1 terminal voltage 9.5 V or more, sensor power supply voltage decreases for 0.5 seconds or more.

and potential areas to look in:

Rear speed sensor

Rear speed sensor circuit

Sensor installation

Foreign matter on sensor rotor

Most of those are probably not going to throw up the DTC, without you moving, but it's possible that it can detect problems with the sensor (power supply open circuit and no current being drawn by the sensor from the ECU), without the wheels moving.

I'm sure you are doing this, but just to confirm, the brake pedal pressing for DTC cancellation has to be done with the thing still in diagnostic mode, i.e. with the wire between pins 13 and 4. It's worked for me no problem.

Also, to confirm, for the VSC/ABS ECU the info from techdoc states:

"Clearing the DTCs cannot be performed by removing the battery cable or ECU-IG1 fuse"

If it is a connection/power supply type fault and it can detect it, it not unreasonable for the DTC not to clear. It probably is clearing, but coming back almost instantly.

Sorry, not much help, but I always find diagnosis "by remote control" a bit of a "challenge" at times. Much easier to actually be there

shcm - thanks for the info - I did press the brake peddle whilst still in Diag mode - it has worked before - but not now...turned ignition off several times - still no luck....I think it might be time for Toyota to have a look...

By the way - cleaned the EGR 6 months ago.....

[Smiler AS]

OK - Took wheel off - took ABS sensor out - IT looked clean, cleaned it anyway, replaced and codes still there....

Shorted out PINs 4 and 13 - still getting ABS 33

Tried to clear the codes with pressing brake pedal 8 times within 5 secods or less - Tried several times and they would not clear at all...Diconnected the battery for 20 mins - still the same....

Appart from booking it in at Westlands - any suggestions....(especialy why I can't now clear the errors??)

Think I pumped the pedal extra couple of times than 8 (couldnt remember how many at a time) and it took a sec delay to clear the codes.

Did you see the ring if it looked okay, a squirt of electrical / brake cleaner on the ring wouldnt do any harm to loosen any dirt.

Might be worth going for quick spin, check codes again to see if 38 appears again too?

or if it just stays with 33.

Did the wires look healthy enough?

[Smiler AS]

Just remembered, I couldnt clear codes for a day.

Turned out I had blown the fuse accidently crossing wire for the diagnostic port, think its a brown 7.5amp one in fuse box under glovebox.

I was 96p for two.