Fault Code Advice

[JamesA]

Well after just over a week of having my RAV, I've got an engine light on! Using my bluetooth OBD2 transmitter and the Torque software on my phone, I've read the following codes:

P0420: Catalyst System Efficiency Below Threshold (Bank 1)

P0430: Catalyst System Efficiency Below Threshold (Bank 2)

Does this mean what I think it means? The CAT is on its way out? Also, why 2 banks?

I've got 6 months warranty so shouldn't cost me much if that is the case, fingers crossed, will check the paperwork when I get home.

[pmb]

We had a thread about this way back in Feb 2008 that I contributed to. Do a search on P0420 on TOC and there are plenty of threads. There are 2 banks (can't remember which 2 cylinders each refer to) and 4 sensors in total.

[jedi134]

I have the same software, just wondering if it gives accurate readings. No faults so far on mine, but as its generic ODB, will it give proper fault codes?

[JamesA]

Thanks for that PMB, i'll look a bit further back in my search results in a mo.

Jedi, I believe OBD2 was standardised on petrol cars in 2001 and diesel in 2004, so codes should be the same on any system you care to use. We tested some faults on my Dads Zafira with my kit and his own OBD stuff on his laptop and it reported exactly the same thing on each.

[JamesA]

Done a bit more reading and thinking on this. One thing im still confused about is why im getting the error on both banks at the same time? Isn't it a huge coincidence for either, both banks of the cat to fail at the same time, or 2 lots of sensors to fail at the same time? Is there another reason I'm missing? Something common to both banks that would cause this fault on both at the same time?

[Joylove]

It is rather suspicious to get both out, since I think you have a 1AZ-FE on a 2002 and hence two cats.

Consider probing the resistance between the two black wires of all 4 lambda sensor; this is the heating element. Expect ~4-15Ohms. Open cct = fault and the engine fuelling won't go closed loop.

http://www.toyotaownersclub.com/forums/index.php?showtopic=128709

[JamesA]

Yes I thought it was odd to get both! Thanks for the info, very useful. will go poke it with my meter in a bit and report back.

How do I tell what engine I have? I looked in my handbook ad it give me 3 options :/

The RAV is a feb 2002 model, 3 door, auto, petrol VVTi.

[Joylove]

Think it's stamped on the block next to the driver wheel arch.

[JamesA]

Yep got it, thanks again. It is a 1AZ-FE, off to poke it with a meter!

[JamesA]

Ok so ive tested the sensors. Looking at the picture above here are the results:

Top Left - 1.4 ohms

Top Right - 1.3 ohms

Bottom Left - 13.4 ohms

Bottom Right - 13.9 ohms

All sounds rather low to me, any thoughts chaps?

[Joylove]

Low is good, it's a heater coil.

I had hoped they would all be the same resistance.

It is not unknown in the BMW world that non-BOSCH O2 sensors that come in at 15R can throw a fault with the ECU, which is expecting sub 4R. Dunno if the same is true of the RAV4 system.

I have just replaced my 4 O2 sensors with genuine DENSOs, I can measure them for you, but it'll have to be after work because the cart is at home; and possibly tomorrow lunch time due to the dark.

EDIT: I am in no way meaning to lead you down a alley that your sensors are faulty, ou don't have the faults codes I had (P1135, P1155). If someone comes along with a more experienced idea then please do listen to them as I could be wrong. If those O2 sensors have been recently changed, have you tried clearing the faults to see if they return?

[JamesA]

That would be great if you could test yours so i can get some idea of what to expect. Maybe they are cheap ones giving the same problem as the BMW's. Fingers crossed!

Going to see if my friendly local garage can check the emissions and see if there is a CAT problem. Still waiting for the dealer i bought it from to get back to me :/

[firemac]

It is rather suspicious to get both out, since I think you have a 1AZ-FE on a 2002 and hence two cats.

Consider probing the resistance between the two black wires of all 4 lambda sensor; this is the heating element. Expect ~4-15Ohms. Open cct = fault and the engine fuelling won't go closed loop.

http://www.toyotaown...howtopic=128709

" a 1AZ-FE on a 2002 and hence two cats." Two cats!!?? Pls tell me this is wrong! I had to replace "the catalyst" (Mr. T dealer-speak) earlier this year on our 02 VVTi after a series of sensor faults/replacements and there was no mention of there being more than one!

Please tell me that I'm not going to face another cat failure in due course.......

[Davrav]

It is rather suspicious to get both out, since I think you have a 1AZ-FE on a 2002 and hence two cats.

Consider probing the resistance between the two black wires of all 4 lambda sensor; this is the heating element. Expect ~4-15Ohms. Open cct = fault and the engine fuelling won't go closed loop.

http://www.toyotaown...howtopic=128709

" a 1AZ-FE on a 2002 and hence two cats." Two cats!!?? Pls tell me this is wrong! I had to replace "the catalyst" (Mr. T dealer-speak) earlier this year on our 02 VVTi after a series of sensor faults/replacements and there was no mention of there being more than one!

Please tell me that I'm not going to face another cat failure in due course.......

One CAT split into two 'banks', two outlets from manifold into each bank...........

[firemac]

It is rather suspicious to get both out, since I think you have a 1AZ-FE on a 2002 and hence two cats.

Consider probing the resistance between the two black wires of all 4 lambda sensor; this is the heating element. Expect ~4-15Ohms. Open cct = fault and the engine fuelling won't go closed loop.

http://www.toyotaown...howtopic=128709

" a 1AZ-FE on a 2002 and hence two cats." Two cats!!?? Pls tell me this is wrong! I had to replace "the catalyst" (Mr. T dealer-speak) earlier this year on our 02 VVTi after a series of sensor faults/replacements and there was no mention of there being more than one!

Please tell me that I'm not going to face another cat failure in due course.......

One CAT split into two 'banks', two outlets from manifold into each bank...........

Ah, thanks for that clarification (massive sigh of relief!!!!)

[Joylove]

That would be great if you could test yours so i can get some idea of what to expect.

1.3R pre cat, 13R post cat.

[JamesA]

Cool, thanks. Garage over the road is going to do an emissions test for me free as ive been a customer for a logs time, will see what that shows.

[Joylove]

Another test for 02 sensors (Although I am thinking now this may be a cat problem) is to view the voltages on the other two wires. They should flip between ~0.7V and ~4.7V (S1) or ~0V and ~1V (S2) while under closed loop control, indicating rich or lean mixture. Unfortunately there are two problems, one you need an analgue Voltmeter because they toggle too fast for a digital meter, and two the connectors are waterproofed and you can't get a probe in to the contacts; unless the ECU pins are available.

As a partial aside, you could consider getting a J1534 X-horse for about £55 and using techstream. The OBD2 data rate is also too slow to catch the toggling however.

[pmb]

Googled J1534 with an without X-horse and it came up with nothing. Any links? Similar to an ELM327 adapter? Also is techstream available to the public? I know there are free progs such as easyobdII but get the impression this is for professional users.

[Joylove]

Damn that should be J2534 aka 'pass thru'. It's similar to, but not supported by, an ELM interface. Basically it's yet another communication protocol which is oly supported by a few adaptors with ARM CPUs inside.

I have this one, paid £55 for mine a few months back

http://www.ebay.co.uk/itm/MINI-VCI-TOYOTA-TIS-CABLE-diagnostic-cable-/330642193532

[jedi134]

Damn that should be J2534 aka 'pass thru'. It's similar to, but not supported by, an ELM interface. Basically it's yet another communication protocol which is oly supported by a few adaptors with ARM CPUs inside.

I have this one, paid £55 for mine a few months back

http://www.ebay.co.uk/itm/MINI-VCI-TOYOTA-TIS-CABLE-diagnostic-cable-/330642193532

[JamesA]

Ooh thanks for that, will have to pick one of those up I think!

I've got an Avo 8 kicking about here which is about as good as it gets for analogue meters in my opinion, also got a hand held oscilloscope (I'm a radio ham so I have all sorts of test kit). One of them should be able to show me how its switching.

[Joylove]

An AVO! Not seen one of those for years. The access to the signals is the issue; the waterproof plugs have no exposed metal.

[JamesA]

Hmm yeah they could be a problem, will have a look over the weekend in daylight. May be able to feed some thin wire in between the seals.

[IanXT4]

Not another member of the AVO 8 owners club