Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!

Oxygen sensor wire harness test

More
7 years 21 hours ago - 7 years 21 hours ago #7965 by babajis2010
Hello guys, I'm glad to be here after watching all the great videos on YouTube.
I am from Sweden and I bought a Toyota Avensis verso 2002 gasoline vvti with DTC's P1135, P1155, P0161.
I discovered that the two A/F sensors upstream are not the right part number for the car and I have ordered the right OEM part from Toyota company here. The downstream sensors are the right part for the car and I have done resistance test reading and continuity tests for both downstream sensors and got 13.9ohms and 13.2ohms with beep sound for continuity (FSM spec for ohms is 11-16ohms). So it looks like my downstream sensors are good but one of them still throws the DTC code P0161. I am looking at checking all the 4 wire harnesses just to be 100% sure everything is right.
My trouble now is I am following my car's FSM (factory service manual) on the troubleshooting.
Step 1. Check ECM for voltage: I've done that step correctly and got 11.9v (FSM states 9-14v)
Step 2. Check oxygen sensors: I have ordered for two new upstream sensors and done tests for the two downstream sensors
3. Check wire harness or connector (ECM-oxygen sensor): I am stuck here and need help on this
4. Check wire harness or connector (oxygen sensor - EFI relay): I am stuck here also.
Also I want to find out if the A/F sensors are bank specific, as there are two part numbers for the upstream sensors and also two part numbers for the downstream sensors.
Downstream sensors (89465-44050 and 89465-44060), which should go to bank 1 and 2
Upstream sensors (89465-42020 and 89465-44030), which should go to bank 1 and 2
Your kind help would be so much appreciated
Attachments:
Last edit: 7 years 21 hours ago by babajis2010.

Please Log in or Create an account to join the conversation.

More
7 years 3 hours ago #8030 by Tyler
Hey there, glad to have you with us! :cheer:

That flow chart sucks! :lol: No way I'm ohm testing all those wires, especially the downstream ones. What a pain! Just to be clear, P0161 is a downstream heater code, correct? That's the generic definition here in the US, but I'm not positive it correlates to the same thing overseas.

I say skip all that stuff and keep it simple. I see you already found battery voltage at the connector, so the next thing I'd suggest is starting the engine to get the O2 heaters running. Backprobe the other heater wire, sensor plugged in, and take a voltage reading. You should see some kind of pulse width modulated ground, which you can also verify with a test light connected to B+.

If you have power and control all the way out to the sensor, and still set a heater code, then I'd suggest a faulty O2 sensor. Let us know what you find, and we can suggest further testing.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8039 by Andy.MacFadyen
According to my listing the difference between the left and right pre-cat sensors seems the wire length, there may (?) also be differences in the details socket design to prevent cross connection.

As Tyler said using voltage and ressistance tests especially unplugged tests can be misleading you need to test under a realistic curent load.
One test that may help is to back pin the connection and use a high wattage tungsten filament test lamp beteen the sensor heater power and ground connections, then trying it between the power and engine ground and also measture the voltage between the sensor heater ground and engine ground.
The heaters appear to be ground side controlled by pulse width modulation so I would expect to see some voltage on the ground wire when the engine is warm.

" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)



Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8047 by babajis2010
Thanks Tyler and Andy. I will follow your instructions once I get the right sensors tomorrow. I have also bought an OBD2 wifi scanner that can read live data so I know what's going on during current load.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8233 by babajis2010
I have installed the oxygen sensors upstream and downstream and erased the codes and MIL disappeared. I have done one trip and two trips detection logic and I don't have any DTC's and no MIL.
The car before the sensors fix and also after the fix doesn't start in like 2 seconds of turning the ignition key, you have to hold the key while the engine spins like 5 seconds before it starts which is quite different from my other car that starts at a blow.
I have below the live data if you guys could make any sense out of this for me, all I want is the car to start fast, function optimally with lower fuel consumption.
And also during cold start the RPM is like 1800 at idling, and when it's properly warm it goes to 740RPM, wondering if that is normal. Shouldn't the RPM be 740 immediately whether cold or warm.

FUEL SYSTEM STATUS
ECU 1. 2) closed loop: using O2 sensor for fuel mix
Engine load. 21.96%
Engine coolant temperature. 67.00 degrees Celsius
Short term fuel trim % - Bank 1. Minus 19 to minus 21.09
Long term fuel trim % - Bank 1. Minus 8.59
Short term fuel trim % - Bank 2. Minus 19 to minus 21.09
Long term fuel trim % - Bank 2. Minus 6.25
Engine RPM. 738
Timing advance. 9.5 - 10 degrees
Intake air temp IAT. 30.00 degrees Celsius
MAF air flow rate. 2.96 grams/sec
Throttle position. 12.55%

OXYGEN SENSORS 1 PRESENT
ECU1. 00110011
0212(Bank 1). 0.7 - 0.85v
0212(Bank 2). Not used. %
0222(Bank 1). 0.7 - 0.78v
0222(Bank 2). Not used. %

OBD STANDARD
ECU1 EOBD (Europe)
02S1 (Bank 1). 0.9 - 1.008v
02S1 (Bank 2). 3.344%
02S5 (Bank 1). 0.81 - 0.997v
02S5 (Bank 2). 3.2 - 3.315%
Attachments:

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8243 by Tyler

babajis2010 wrote: I have installed the oxygen sensors upstream and downstream and erased the codes and MIL disappeared. I have done one trip and two trips detection logic and I don't have any DTC's and no MIL.


Nice. B) Toyota's are pretty quick to pick up heater faults, so I'm sure you're in the clear as far as the sensors themselves.

The car before the sensors fix and also after the fix doesn't start in like 2 seconds of turning the ignition key, you have to hold the key while the engine spins like 5 seconds before it starts which is quite different from my other car that starts at a blow.
I have below the live data if you guys could make any sense out of this for me, all I want is the car to start fast, function optimally with lower fuel consumption.


Thanks for including the data! :cheer: The negative fuel trims stand out right away. Around 25-30% total trim for both banks is definitely outside normal, and indicates and strong rich condition. A fuel issue would also account for the long crank time.

Couple things I'd want to know before going further. One, I'd be interested to watch the fuel trims at idle while generating a large vacuum leak. This will (hopefully) force the O2 sensors lean, and generate a short term fuel trim positive correction. This confirms that the new sensors are capable of responding correctly. From chapter 4:



Two, I'd be interested to see how those trims change during a test drive. Do they get worse? Better? Knowing how the trims react to load changes may help us narrow down the problem.

Unfortunately, we never got this 2.0L GDI engine in North America, so I'm not terribly familiar with it. :unsure: Not sure what kind of problems they had with this injection system, if any.
Attachments:

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago - 6 years 11 months ago #8245 by borntoroll
Are there 2 cats (2 banks) for a 4 cyllinder engine?
That are quite negative fuel trims for both banks. Fuel pressure is to be checked. MAF readings seems normal at 3 g/s
How does it idle? If you slighlty depress gas pedal does it start better?
Last edit: 6 years 11 months ago by borntoroll.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago - 6 years 11 months ago #8257 by babajis2010
I have done the tests of load and short term fuel trims
When I drove around and watched the STFT bank 1 and 2, they moved up and down between +5 to -21.09
When I introduced a big vacuum leak after the MAF sensor, the STFT also moved up and down. About same value as above.
After this last check of introducing vacuum leak at idle I noticed something.
STFT Bank 1 moves between -7 to -13
STFT Bank 2 moves between -17.97 to -21.09

Can I pass emission test this way and later fix this problem because I have the emission test tomorrow, or do I reschedule.
I was wondering since I don't have any DTC's and no MIL it won't be a problem to pass emission. I need advice on this also
Attachments:
Last edit: 6 years 11 months ago by babajis2010.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8259 by babajis2010
It idles fine when it's warm. When I depress gas pedal it doesn't change the start time, it's still doing half starting.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8266 by Tyler

babajis2010 wrote: Can I pass emission test this way and later fix this problem because I have the emission test tomorrow, or do I reschedule.
I was wondering since I don't have any DTC's and no MIL it won't be a problem to pass emission. I need advice on this also


I don't know what kind of testing they'll do for emissions in Sweden. :unsure: But if it's just a simple check for codes, monitors and if the MIL works, then I think you're in the clear. No emissions testing programs here in the States look at fuel trims as part of the inspection.

If it's a tailpipe test, then... I'm not sure? The rich condition appears to be corrected for, so (theoretically) the gas analyzer won't notice.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8269 by babajis2010
I need to mention that my engine coolant temperature is 67 degrees Celsius instead of 80-95 after warmed up, I will double check on this again.
I read one of the problems for a rich fuel condition is a stuck open thermostat. When the engine is idling and all of a sudden the radiator fan kicks in the STFT changes drastically, more like the thermostat working for the engine coolant affects my STFT also.
I am planning on cleaning the MAF, look if the right plugs are in the car (NGK), and see if I have any changes.
So apart from MAF and spark plugs what other specific components can cause a rich fuel mixture condition.
The pre inspection paper when I bought the car before I changed all the sensors complained about CO/HC too high at idle.

I read the RPM at cold start at 1400 is pretty normal before it comes down to 750 RPM when engine is properly warmed.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago - 6 years 11 months ago #8277 by babajis2010
Thanks Tyler.
The emission test here is tail pipe. They plug a big hose at the tail end of the exhaust pipe.
You are right the abnormal STFT seems to be corrected or allowance made for by the sensor and ECM and that's why the LTFT is in the single digit.
I think I should be able to clean MAF, check plugs and see if the coolant temperature sensor or thermostat is working properly before I go for emission in the afternoon.
I will come back with some updates later.
Last edit: 6 years 11 months ago by babajis2010.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8297 by babajis2010
I failed emission test today. Before I went for the test, I was at Toyota company to buy the recommended denso plugs for the car and also cleaned the MAF sensor filament with cleaner I got also from Toyota. After this my car starts better now and the fuel trims immediately became better.
The emission results below
CO and HC too high
CO at idle was 0.8 (0.5 is the maximum allowed)
CO at 2500 rpm was 0.1 (0.3 is the maximum allowed) so I passed CO at higher rpm
HC was 118 (100 is the maximum allowed)
Lambda: 1.01 (0.97-1.03 is the range allowed) so I passed on that also.

What next do I need to do to bring down the CO and HC values.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8298 by babajis2010
Short term fuel trim Bank 1 at idle 900rpm 0 to (-3.91)
1500rpm +3 to (-3.91)
2500rpm +5.47 to 0

Long term fuel trim Bank 1 at idle 900rpm -13.28 to -14.06
1500rpm -10.94
2500rpm -10.94


Short term fuel trim Bank 2 at idle 900rpm -0.78 to -3
1500rpm +3.91 to -2.34
2500rpm +3.12 to +10.94

Long term fuel trim Bank 2 at idle 900rpm -18.75
1500rpm -12.50
2500rpm -9.38 to -10.16

I do not experience anymore the engine stalling on the highway at 120km/h, I had that problem when overtaking before when the car just slows down as you struggle to overtake a truck. After I changed all my sensors and plugs I don't have that problem anymore. The vehicle runs so fast now but I notice the RPM at 120km/h stays at 3100rpm without dropping, isn't that going to consume gasoline. 2750rpm at 100km/h.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago - 6 years 11 months ago #8307 by Toolman10000
deleted.
Last edit: 6 years 11 months ago by Toolman10000.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8323 by Andy.MacFadyen
With high CO and high HC I solve the HC and the CO normally takes care of itself.
I looks to me like you still have incomplete combustion due excess fuel.
You say the engine is running well so we can probably discount misfire --- but if you have the facility on your scanner check the misfire counters.
An engine running at 65c isn't good, if the reading is correct then anew thermostat may well be the answer.
Another possibility is the engine oil is contaminated with fuel due to the over rich fueling, this would be made worse if the engine is running cool as less fuel will be cleared from the oil by evaporation.
Although the MAF is now working it still has question mark over it.
The Cat is also apparently working with a good cat you would expect to see a fairly steady output on the down stream sensor essentially the downstream sensor should mainly flat line (usually rich) at stead idle and respond to throttle follwed by lift off and retrurn to idle.
To put your mind fully at ease over the Cat you could do a reserve oxygen storage test. This is essentially forcing the fueling rich for several seconds then allowing it abruptly to go lean and observing the difference in reaction between the upstream and downstream sensors. There should be a distinct delay between the step-change when upstrean goes lean and downstream goes lean.

There are different ways of doing it Paul's favoured method is to use propane introduced into the intake.

The details are in section 5/23 of Pauls book.

For a rough and ready version I graph the sensor ouputs on a roadtest -- full throttle sustained for few seconds followed by lifting off the throttle (injector cut ) if I see any distinct delay between the upstream sensor going lean the downstream sensor going lean I am pretty confident the Cat is good enough for an emmisions check.

" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)



Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8329 by babajis2010
Just to isolate my car's problems one by one.
I have now decided to do a comprehensive service for the car since I bought it used.
Oil and oil filter, fuel filter, air filter, PCV valve, clean the EGR valve and check the entire EGR system. I have put new Denso manufacturers recommended plugs.
I monitored engine coolant temperature with my wifi OBD when I was driving at 80km/h for 25 mins, my engine coolant temperature stopped at exactly 70*celcius all through the drive and then when I got to the parking lot and left the engine idling the engine coolant temperature rose to 85 in about 10mins.
I have ordered a new thermostat and anti freeze water to flush out the entire coolant system.
Now this is the part I need more expert advice. I bought two brand new Denso A/F sensors from Toyota and bought the other 2 downstream used from a Toyota Avensis Verso 2004 and mine is 2002, but the seller said they would work since its same part numbers (89465-44050 and 89465-44060), but the problem now is my wifi OBD live data shows not used for the 2 used downstream sensors but it shows voltage going up and down for the upstream as I rev the engine, and then still on the OBD live data in another section it shows general voltages for all the sensors but those are not influenced by the rev of the engine. I am attaching all the data of my sensors. If the 2 downstream sensors are not working will they cause any drivability issues. Because I thought all the 4 sensors should show some voltage readings at least and the upstream ones should bounce around more while the downstream sensors voltages remain kind of stable.
Attachments:

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago - 6 years 11 months ago #8330 by babajis2010
Then the other voltage readings of the sensors I wrote about before. I will look into the CAT after the comprehensive service. I tried to separate the sensors for the mechanic but he mixed all together and said the sensor connectors are not the same and no way you can fit in any sensors for the wrong sides. He even practicalized it and I saw they didn't fit when put in the wrong connectors. Help me analyze my sensor data and see if it makes any sense.
Attachments:
Last edit: 6 years 11 months ago by babajis2010.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8342 by Tyler

babajis2010 wrote: Now this is the part I need more expert advice. I bought two brand new Denso A/F sensors from Toyota and bought the other 2 downstream used from a Toyota Avensis Verso 2004 and mine is 2002, but the seller said they would work since its same part numbers (89465-44050 and 89465-44060), but the problem now is my wifi OBD live data shows not used for the 2 used downstream sensors but it shows voltage going up and down for the upstream as I rev the engine, and then still on the OBD live data in another section it shows general voltages for all the sensors but those are not influenced by the rev of the engine. I am attaching all the data of my sensors. If the 2 downstream sensors are not working will they cause any drivability issues. Because I thought all the 4 sensors should show some voltage readings at least and the upstream ones should bounce around more while the downstream sensors voltages remain kind of stable.


Did those PIDs work before? :huh: I ask because it's not at all unusual to see the O2 percentage PIDs coming back as 'UNUSED'.

Those are actually oxygen sensor fuel trim PIDs, but since your downstream sensors have nothing to do with overall fuel trim, that PID is quite literally unused. I have a much better explanation in this thread , along with some captures from my own Ford Escape that shows the same thing you saw. ;) Short answer, don't worry about it.

Aside from that, the signals look OK to me. A steady downstream reading is usually an indication of a functioning catalyst. If you wanted to make double sure that everything is OK, you can create a large vacuum leak and make sure the downstream sensors respond not long after the upstreams.

Please Log in or Create an account to join the conversation.

More
6 years 11 months ago #8349 by babajis2010
Tyler you are awesome and thanks for your explanation. I never checked if the PIDs worked before in the old sensors because I didn't have the OBD wifi scanner then. But now I'm glad it's a normal condition for all my sensors.

When I changed the spark plugs I noticed the wire harness for plug number 2 was sitting so tightly under the plug cap of spark plug number 3 and the wire was so pressed but I didn't tear open the wrap covering the wires to check if any wires have broken. So now I have a new set of spark plugs, how do I check for current integrity in the plug wires just to be sure the plugs are getting the right amount of juice to fire them up properly, can I do anything like a resistance and voltage check using a DMM in all the spark plug wires rather than checking for sparks or all are important (resistance, voltage and spark tests).
I want to do a smoke test for any vacuum leak myself, can I ask my smoking friend to puff some cigarette smoke in any of the engine inlet hoses. I am trying my best to eliminate all the culprits for my car's fuel consumption and emission failures.
When the car is sitting idle and I rev the engine to the max almost the highest RPM, the engine sounds very great, so it means the problem is not when it's just standing idle but when the car is moving.
When I watched many YouTube videos I noticed Americans seem more informed about car fixing than the Europeans. Americans repair while Europeans just change the parts, so most mechanics here are not interested in taking time to fully diagnose a car's problems....thank goodness for the internet, at least the govt can't stop me from seeking help abroad online from good people like you guys. :)

Please Log in or Create an account to join the conversation.

Time to create page: 0.287 seconds