P1135 Error Code Related to Fuel/Heater Issues? Gen 4

[SaganGathering]

I have a Toyota Camry LE (4 cyl; automatic, 5S-FE) 2001 (1/30/2000 delivery date) with 123K miles that has baffled every mechanic it's been brought to- even after having 4 different computers hooked to it. But first my immediate problem:

I have that vague P1135 error code and wonder if a noob like me could fix it. How do i find out if the fix really requires replacing an O2 sensor (and if so where do i get a Toyota Camry O2 sensor?) Are there easier/cheaper fixes to try before that? I'm under the impression that the Air/Fuel ratio sensor is just a fancy O2 sensor with a heating element in it.


The Check Engine light came on Saturday night after some quick driving up the steep & winding hills of Ithaca. A Sunday visit to AutoZone's for their free status checker found only a p1135 error: Manufacturer's Air / Fuel Control. The guy there said an O2 sensor problem was apt to turn up more than just one error code, so he thought my O2 sensor was probably OK. (Is this typical?) I checked the air filter- it looked fine. I found chewed pumpkin seeds and sandy debris under the filter and vacuumed it out. I had rodents up in there and wonder if fine hairs could have slipped through the filter. [I bought the car used in Oct. 2006 with 92K miles (it's my first-ever car!!) and as far as i can recall since i bought it, never had the air filter replaced- it's aways stayed clean.] Cleaning that junk out from under the air filter chamber did not reset the p1135 Check Engine condition.

Q1) Should i go someplace and have the computer reset to see if the Check Engine light comes back on? I'm wondering if the junk from under the air filter caused the error (but i doubt i'll get off that lucky).


After getting back home a couple of days later (and some 150 miles later), I went to one of my regular garages and the PDF they had on the 2001 Camry P1135 error said something about a sensor Heater and something about a return circuit. I imagine the heating element is inside the sensor itself. They said it could be an electrical issue or an O2 sensor or even something else. They did not say which one might be the problem but said they had better computer diagnostics to narrow it down (sadly, they were booked full). This guy did warn that a rich fuel mix could damage or ruin my catalytic converter or maybe an O2 sensor (another mechanic elsewhere also said this could happen). As it is near the end of the month they are swamped with people needing Inspection. That's the case with every garage i tried here. I need to go out of town this weekend and am frustrated because i can't seem to get the issue addressed until next Tuesday at the earliest. Which is too late.

Q2) In a worst case scenario (overly rich fuel mix?) how far can i go before causing damage to the catalytic converter or other parts? If i drive from garage to garages am i asking for trouble? I don't want to screw up my car.


I have no idea if this is connected to the p1135 error code, but: Over the previous 2-3 weeks it seemed as if my hood area was hotter than it should be, complete with that "driving in 90 degree weather" smell that engines can make. This is even with our weather being much cooler than is typical for this time of year. 70 degrees is warm enough for this to smell happen. I did notice a bit of this in late winter come to think of it. I also noticed that the in-dash thermometer seems to report that it's hotter than it really it outside. I think i saw a 9 degree difference once. That's quite a bit! My cooling system looks OK and here's plenty of coolant. Should i drain the coolant and replace it?

Inside the car, even with the vents turned off, some air still comes in- possibly more than i recall from when i got it originally. The problem is that the air coming in seems warmer than it should be. If it's ~72 degrees outside, it starts to get a too hot inside. I can turn on the fan and select the bluest setting (which i assume means air is taken directly from the outside) and still that air is unreasonably warm. That leaves me the option of driving with windows down or the AC on- neither of which helps my terrible MPG situation. I lost my job and gas prices are climbing. :-( In the winter, the car seems colder than it used to be- that is, the heater doesn't put out air that seems as hot.

I also wonder if the p1135 error is related to a problem i've have for the past 20 months or so. Starting around Sept. 2007 there was a HUGE drop in fuel efficiency. I had one of those lucky wunder Camrys that seemed to get over 36 MPG highway, and seemed to get over 28 in the city. Then i suddenly started getting as little as 13 MPG city (winter) and 15-17MPG in the summer, and 17-23 MPG highway. At 13MPG i may as well drive a hummer! My driving habits have not changed- i always take off gradually and adjust my speed when i see a red light in the distance so as to avoid having as many stop/starts. And yet i was getting 13MPG! After a few seafoam/lucas treatments, at the right temperature, on a level highway, at exactly 55MPH, on cruise control, i can just about get back to about 30-32 MPG (i have no way to know for sure of the seafoam/lucas is what caused this partial correction). I used to be able to easily do 65MPH and get this many MPG. So i'm still far under what's normal for this 2001 Camry. And city fuel economy (or hilly driving) still exacts an abnormal efficiency penalty not seen until Sept. 2007. Its fuel economy seems to vascilate in ways it never did prior to Sept. 2007.

I tried the obvious corrections: proper tire pressure, seafoam, lucas, new spark plugs (my fuel economy seemingly got worse after the new plugs) . The timing belt was was last addressed at 82K miles (10K miles before i bought the car). I had a Transmission Flush done at about 112K miles when i found out the previous owner *never* had the transmission fluid changed. None of this seems to have put things back to normal.

Frick & Frack the Tapper Brothers on NPR once mentioned in passing that a bad thermostat can affect fuel economy so i'm wondering if perhaps one or more of these issues are connected.
　
　

[hill8570]

Heh...how did a Cali spec rig get out to New Yawk?

OK, one thing at a time, here. P1135 is easy enough to check out, so let's do that first.

Rather than do the diag in the order given, I'd first check the A/F sensor to see if the heater element is fried -- that's usually the cause of this code. First pop off the connector for the A/F sensor, and check the resistance of the heater in the sensor...see page 59 for the procedure. If it buzzes out more than a couple of ohms (probably will be infinite), then the A/F sensor needs to be replaced. If so, www.sparkplugs.com has decent prices (although even inexpensive A/F aren't cheap).

[SaganGathering]

Originally Posted by hill8570

Heh...how did a Cali spec rig get out to New Yawk?

You've got me. I didn't even know this was a California spec'd car! How can you tell?

OK, one thing at a time, here. P1135 is easy enough to check out, so let's do that first. See page 161 for the diag page for P1135.

Thanks for the URL! However there is no page 161 in that^ PDF. It only goes up to page 141. There seem to be a bunch of other files that make up a whole manual:

but i can't seem to get at them.


I did find a section in that PDF on the A/F sensor, but the images weren't clear enough for a total noob like me. Line drawings are fine but these were too blocky for me to really get much out of (being a neophyte and all). I'm still willing to give it a go. Also, i don't know if my car is a California spec. How do i tell?

Rather than do the diag in the order given, I'd first check the A/F sensor to see if the heater element is fried -- that's usually the cause of this code. First pop off the connector for the A/F sensor, and check the resistance of the heater in the sensor...see http://www.camrystuff.com/manuals/Gen4/SFI.pdf page 59 for the procedure.

Sounds like a good approach. (I wonder if the Chilton, Haynes or Bently Camry repair manuals are helpful for an absolute beginner like me, IE which one is best?). There's an in-document link to a DI-152 on that page, but it goes nowhere. Any idea what DI-152 is?

If it buzzes out more than a couple of ohms (probably will be infinite), then the A/F sensor needs to be replaced.

So no way to replace just the heating element itself? :-( It's probably just a resistor, right? Sigh.

If so, www.sparkplugs.com has decent prices (although even inexpensive A/F aren't cheap).

Since i am under the impression that i should prefer a Toyota brand A/F sensor, what's the part# or ID for a 2001 Camry A/F sensor, and what's a good price? A pal's dad at a local dealer can get it for $170 (plus 9.5% tax - ouch) but i suspect it's available online for less... but how can i be sure i'm not getting counterfeit "Toyota" parts that way?

[JohnGD]

New York and Massachusetts also use the more stringent California emissions standard.

[JohnGD]

Upstream: Rockauto.com plus shipping.

DENSO Part # 2349010 More Info {OE-TYPE OXYGEN SENSOR #8946733020}
FRONT; Calif Only $126.79

[hill8570]

Originally Posted by SaganGathering

You've got me. I didn't even know this was a California spec'd car! How can you tell?

It threw a P1135 -- a code associated with A/F sensors. Only Cali-spec 5S-FE rigs of that year had A/F sensors.

Originally Posted by SaganGathering

Thanks for the URL! However there is no page 161 in that^ PDF. It only goes up to page 141. There seem to be a bunch of other files that make up a whole manual:
http://camrystuff.com/index.php?page=Gen4_Manuals
but i can't seem to get at them.

The Diagnostics chapter goes for roughly 900 pages. Sounds like you've got computer problems, too...

Originally Posted by SaganGathering

I did find a section in that PDF on the A/F sensor, but the images weren't clear enough for a total noob like me. Line drawings are fine but these were too blocky for me to really get much out of (being a neophyte and all). I'm still willing to give it a go. Also, i don't know if my car is a California spec. How do i tell?

There's probably something floating around on the net with a clearer drawing of the connector layout. Don't know, offhand. Maybe someone else has a ref?

Originally Posted by SaganGathering

Sounds like a good approach. (I wonder if the Chilton, Haynes or Bently Camry repair manuals are helpful for an absolute beginner like me, IE which one is best?). There's an in-document link to a DI-152 on that page, but it goes nowhere. Any idea what DI-152 is?

Accuracy-wise, I prefer the factory manuals. Chilton and Hayes tend to go into a bit more detail than the FSM, 'tho. DI-152 means page 152 of the Diagnostics chapter -- the chapter I gave you the link to earlier.

Originally Posted by SaganGathering

So no way to replace just the heating element itself? :-( It's probably just a resistor, right? Sigh.

No such luck. Never tried taking one apart. Given the temperature extremes it has to go through, I doubt any off-the-shelf resistor could handle the environment.

Originally Posted by SaganGathering

Since i am under the impression that i should prefer a Toyota brand A/F sensor, what's the part# or ID for a 2001 Camry A/F sensor, and what's a good price? A pal's dad at a local dealer can get it for $170 (plus 9.5% tax - ouch) but i suspect it's available online for less... but how can i be sure i'm not getting counterfeit "Toyota" parts that way?

$170 isn't too bad for Toyota-brand. P/N 89467-33020 runs roughly $155 from the least expensive online dealers ( such as www.1sttoyotaparts.com ), and you'd have to pay shipping.

Denso or NGK are both decent generic brands (Toyota OEMs most of their electrical components from them) just get one that is "OE equivalent", so you don't have to hassle with splicing your old connector onto a generic sensor. Sparkplugs.com or the previously-mentioned Rockauto are both reputable outfits.

[jmborchers]

My wife's car did this. Turned out to be a bad battery [still would pass a battery test]. We only learned that after replacing the A/F sensor and computer. The heater element should measure somewhere around 1 ohm. The detection circuit checks if the heater is either shorted (>8 amps or <1 amp [I think])

If you replace the sensor use a dealer part. I got ours for $135 at the dealer.

I'm in PA the car also managed to get out here from CA.

If you really need a computer contact me. I have it for a 1999 5SFE CA model.

When this code is thrown the car operates in "safe" mode for ignition / emissions. This is what causes the gas mileage to go way down.

[hill8570]

Originally Posted by SaganGathering

I did find a section in that PDF on the A/F sensor, but the images weren't clear enough for a total noob like me. Line drawings are fine but these were too blocky for me to really get much out of (being a neophyte and all). I'm still willing to give it a go.

If you follow the wire up from the A/F sensor to the engine and disconnect there, look closely at the wires going into the connector. Two should be black. There will also be a blue and maybe a white wire. What you want to do is measure the resistance between the two black wires to check the heater.

[SaganGathering]

Originally Posted by hill8570

It threw a P1135 -- a code associated with A/F sensors. Only Cali-spec 5S-FE rigs of that year had A/F sensors.

Good catch. From what the Haynes repair manual said, all 2001 Camrys used Air/Fuel ratio sensors (not just an O2 sensor in the manifold as previous Camrys did). The manual also seemed to suggest that all year 2001 Camrys were California spec'd cars. Does this fit with what you know?

I don't like this Haynes Camry repair manual one bit, but here's what it says on the topic of 2001 Camrys and California and the air/fuel sensor:

"On 1997 through 2000 non-California models, the upstream sensor is a heatd oxygen sensor; on 1997 through 2000 California models, the upstream sensor is an air/fuel sensor. All 2001 models (California and non-California) us an air/fuel sensor upstream."

So:


Q1) Is there an advantage is asking for a California-spec'd air/fuel sensor? Do they even exist?

The Diagnostics chapter goes for roughly 900 pages. Sounds like you've got computer problems, too...

Can you Re-Check the link you posted? The PDF appears intact, and had 141 pages. Windows reports it to be 2,434 KB.

There's probably something floating around on the net with a clearer drawing of the connector layout. Don't know, offhand. Maybe someone else has a ref?

I broke down and got a Hayne Camry repair manual. You'd think by now they'd have corrected all the obvious problems in that manual. They've only had like 8 years to do so. I was able to tease enough out of it to decide to make a DIY attempt, but am uncomfortable trusting info coming from shoddy manuals.

Accuracy-wise, I prefer the factory manuals. Chilton and Hayes tend to go into a bit more detail than the FSM, 'tho. DI-152 means page 152 of the Diagnostics chapter -- the chapter I gave you the link to earlier.

Flying Spaghetti Monster? I was told today that the Chilton manual costs about 2X what the Haynes manual costs. I wonder if it's that much better?
There is no page 152 in that PDF. I downloaded it twice.

$170 isn't too bad for Toyota-brand. P/N 89467-33020 runs roughly $155 from the least expensive online dealers ( such as www.1sttoyotaparts.com ), and you'd have to pay shipping.

I located my air fuel sensor and it says both Toyota and DENSO printed on it!

Getting the Toyota brand A/F sensor locally (through a well-placed contact) will be about $187 after taxes. Thanks for the P/N too. I shouldn't think shipping would be more than $10 (free shipping is always a plus). So i'd save about $22 by going with www.1sttoyotaparts.com . The big short-term question is, can i keep driving my car until the part comes in? Most of the mechanics i've talked to think there's a risk in driving it: too-rich of a mix could compromise my catalytic converter or downstream O2 sensor. I've already put about 200 miles since the check engine light came on.

Denso or NGK are both decent generic brands (Toyota OEMs most of their electrical components from them) just get one that is "OE equivalent", so you don't have to hassle with splicing your old connector onto a generic sensor. Sparkplugs.com or the previously-mentioned Rockauto are both reputable outfits.

NGK? never heard of them. But you are obviously right about Denso.

[jmborchers]

Just by stating the code P1135 you absolutely have a CA model car. The dealer's guide tells us this. The CA model car has an A/F sensor (increased range O2 sensor is all it is) all others have a heater O2 sensor.

My wife drove our car for months before I figured out what the problem really was. It's now around 8 months later and there aren't any emission issues.

Although the car goes into safe mode it doesn't inject extra gas, it just doesn't save it.

[SaganGathering]

Funy you mention that. My fuel economy sucks. And in the past few days i've smelled a new smell. And not just the "i'm driving fast in 95 degree weather smell" that i've had for a few months, but something that's vaguely gasoline-esque. Well, sort of. Hard to describe smells, you know?

[SaganGathering]

Originally Posted by hill8570

If you follow the wire up from the A/F sensor to the engine and disconnect there, look closely at the wires going into the connector. Two should be black. There will also be a blue and maybe a white wire. What you want to do is measure the resistance between the two black wires to check the heater.

Thanks Hill, but do you have pinout #'s? I'm reluctant to test by wire color as i have seen many occasions where going by wire color is not reliable. Sometimes there's an assembly goof, or the manufacturer runs low on a particular color.

[SaganGathering]

Originally Posted by JohnGD

Upstream: Rockauto.com plus shipping.

DENSO Part # 2349010 More Info {OE-TYPE OXYGEN SENSOR #8946733020}
FRONT; Calif Only $126.79

Now this is very odd. The 2001 and later Camrys use Air/Fuel sensors there, not oxygen sensors as earlier Camrys did. Rockauto lists an oxygen sensor whose P/N matches the Denso/Toyota A/F sensor in my 2001 Camry right now: 89467 33020

Rockauto does list an Air/Fuel Ratio Sensor, but it's not an original Denso/Toyota or OE part as far as i can tell:

BOSCH Part # 13733 {Wideband A/F Sensor - OE Type - Exact Fit}
Upstream; 4 Wire; Wideband A/F; Check / Replace Interval: 100,000 Miles

It's also nearly $160. Which i kind of expected.

But it's weird that they list an A/F Sensor AND an upstream O2 sensor (which appears to match the A/F sensor installed right now).

[hill8570]

Originally Posted by SaganGathering

Now this is very odd. The 2001 and later Camrys use Air/Fuel sensors there, not oxygen sensors as earlier Camrys did. Rockauto lists an oxygen sensor whose P/N matches the Denso/Toyota A/F sensor in my 2001 Camry right now: 89467 33020

Rockauto does list an Air/Fuel Ratio Sensor, but it's not an original Denso/Toyota or OE part as far as i can tell:

BOSCH Part # 13733 {Wideband A/F Sensor - OE Type - Exact Fit}
Upstream; 4 Wire; Wideband A/F; Check / Replace Interval: 100,000 Miles

It's also nearly $160. Which i kind of expected.

But it's weird that they list an A/F Sensor AND an upstream O2 sensor (which appears to match the A/F sensor installed right now).

Going by name ( Oxygen sensor vs A/F sensor ) is unreliable -- "oxygen sensor" is often used as a generic term for the sensors used to sense the A/F mix in the exhaust.

I *think* Bosch just repackages the Denso part for this rig, but I'm not anywhere near 100% sure on that. I tend to shy away from "Botch" parts on general principle.

[jmborchers]

Originally Posted by SaganGathering

Funy you mention that. My fuel economy sucks. And in the past few days i've smelled a new smell. And not just the "i'm driving fast in 95 degree weather smell" that i've had for a few months, but something that's vaguely gasoline-esque. Well, sort of. Hard to describe smells, you know?

My wife's car also had this smell. Turned out to be the EVAP purge valve. I think it threw a P0441 if I remember correctly.