Check Engine, VSC and Traction Control lights turned on?

Tiny
BUYRITEAUTO21
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  • 2010 TOYOTA COROLLA
  • 241,000 MILES
The check engine light came on my dash. The VSC light blinks and the Traction Control symbol is on. The car does chug a little bit sometimes but otherwise runs fine. Do you know what the cause of this would be?
Saturday, January 7th, 2023 AT 8:18 AM

17 Replies

Tiny
JACOBANDNICKOLAS
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Hi,

What I would start with would be to have the computer scanned for diagnostic trouble codes. Since the check engine light is on, there will be codes stored.

Now, did all of the lights turn on at the same time? Are there any other symptoms you have noticed? Is the ABS light on?

I ask because if there is a failure with one of the wheel speed sensors, it can turn on all the lights you mentioned.

Let me know. Also, if you have already had the computer scanned, let me know what codes were found. If you haven't, it should be done. Often times a parts store will do it free of charge.

Take care and let me know as much as you can that may help me diagnose the issue.

Joe
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Saturday, January 7th, 2023 AT 9:09 PM
Tiny
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I went to AutoZone and they scanned the codes. P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1) came up and so did C1201 (Brake Boost Sensor Circuit Range/Performance.

The ABS light did not come on. The check engine light, VSC light and Traction Control symbol all came on at the same time. The VSC light is continually blinking.

The engine does not idle smoothly. It sounds like it is huffing at times and power fluctuates some.

Thanks
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Sunday, January 8th, 2023 AT 3:00 PM
Tiny
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Hi,

I need to know if you have a 1.8L or a 2.4L engine for the oxygen sensor code. I did some research and found that the stability control and traction control circuits may be in a fail-safe mode due to the engine code (O2 sensors).

Let me know what engine you have.

Take care,

Joe
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Sunday, January 8th, 2023 AT 8:55 PM
Tiny
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I have the 1.8 liter engine.
Thank you
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Monday, January 9th, 2023 AT 10:20 AM
Tiny
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Hi,

I attached the info from the C1201. I highlighted the area of interest. The P2195 falls into the category of an Engine System Malfunction, so the oxygen sensor code is what is likely causing the issue.

If the sensor is frozen lean, chances are it is bad. However, before you replace it, have the computer scanned to see if the lights go out. If they do and then come back on, suspect the sensor needs to be replaced. It could also be a wiring issue, but chances are it is the sensor itself.

If you want to remove and inspect the sensor, here is a link that explains how to test one:

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

Let me know your thoughts and which way would you like to go forward.

Take care,

Joe

See pics below.
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+1
Monday, January 9th, 2023 AT 2:39 PM
Tiny
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How do I have the computer scanned and do you know where the sensor is located?
Thanks
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Monday, January 9th, 2023 AT 6:45 PM
Tiny
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Hi,

The sensor is located between the engine and firewall right before the catalytic converter. To access the sensor will be somewhat of a nightmare because several things need removing. See pic 1 for location.

The remaining pictures are the removal procedures. Note that if there is a step you need help with, let me know and I'll get you the specifics.

As far as the scan, if you remove the sensor and use the link I attached above, you can skip the scan until we confirm if the sensor is good or bad.

Let me know.

Joe

See pics below.
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Monday, January 9th, 2023 AT 7:35 PM
Tiny
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Hi,

I had the upstream oxygen sensor replaced by a service garage. The check engine light and VSC blinking letters and symbol disappeared for about 100 miles of driving after I left the mechanic. They came back on as before. I took it back to the mechanic and he said the new oxygen sensor needs time to adjust to the existing downstream sensor with the way they register with the vehicle computer. He did something which made the light disappear again and now after 50 miles of driving it has come back on like before. I am taking it to him again tomorrow to scan and see if the downstream sensor needs replacing. I also took it to AutoZone and had them scan it. Code P2401 is coming up as an Evaporative Emission Leak Detection Pump Secondary DTC. Would this be related to the oxygen sensor that was replaced?

Thank you
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Sunday, April 2nd, 2023 AT 9:31 AM
Tiny
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Hi,

The EVAP system is certainly tied to the O2 sensors. If there is a leak, it will allow unmetered air to enter the engine. As a result, you end up with a lean fuel mixture and the computer tries to compensate by adding fuel.

On the other hand, I don't see how the vehicle stability control is affected by either the o2 sensor or the leak. That is usually related to a wheel speed sensor. By chance, is the ABS light on or the brake light on?

As far as the new code is concerned, here is the description.

DTC P2401 Evaporative Emission Leak Detection Pump Stuck OFF

Let me know if that is the only code. Also, I don't feel the new code is related to the VSC issue, but I could be wrong as well.

Let me know.

Joe
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Sunday, April 2nd, 2023 AT 6:34 PM
Tiny
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Hi,

I took it back to the mechanic shop today and they scanned the codes in my car. They said that the downstream oxygen sensor is now bad and that the EVAP cannister is also bad. The mechanic said the VSC light, and symbol were on and blinking because the temperature from the faulty oxygen sensor reading was like 700 degrees. The ABS and brake light are not on. Before I left, he canceled out the codes, but they have been reappearing after about 50 miles of driving. Is this a common thing for both sensors and an EVAP cannister to be faulty?
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Monday, April 3rd, 2023 AT 6:34 PM
Tiny
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Hi,

No, it isn't a common issue. Did he do the work and has it taken care of the issue?

Let me know.

Joe
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Monday, April 3rd, 2023 AT 9:00 PM
Tiny
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Yes. The mechanic changed the upstream oxygen sensor. He said that was the bad one according to his scanner. After less than 100 miles of it being changed, the lights all came back on just like before. I brought it back and he said the sensor needs time to adjust to the computer for it to be recognized by the vehicle. He said the lights may just disappear over time after the computer registers the new sensor with the vehicle. I still had him scan the code again and then he said the downstream oxygen sensor was bad and the evap cannister. I would like to believe getting these two parts changed would solve the problem, but im not sure if it even makes sense since the mechanic told me things would correct on its own and then said the downstream sensor is bad and the evap cannister too. Is downstream sensor and evap cannister very difficult to replace?

Thanks
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Wednesday, April 5th, 2023 AT 4:59 PM
Tiny
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Hi,

How is the engine running for you now? Also, the sensors do nothing but send a voltage signal to the powertrain control module (PCM). There is no relearning process or amount of time needed for it to "reset".

Explain how it is now running, the exact codes that are present (most parts stores will scan it for you), and anything you can think of that may help me.

If you could get your hands on a live data scan tool, we can check to see how the sensors are responding. We really don't need to go back to the shop.

Let me know.

Take care,

Joe
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Wednesday, April 5th, 2023 AT 6:55 PM
Tiny
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Hi,

My car seems to be running okay besides the check engine light on and the VSC light on with the symbol blinking.
I was able to use a code scanner and was given the following ones:
P0138 Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2
C1201 Engine Control System Malfunction
P043E Emission System Leak Detection Reference Orifice Low Flow
P2402 Evaporative Emission Leak Detection Pump Control Circuit High
P2419 Evaporative Emission System Switching Valve Control Circuit Low

Thanks for your help
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Saturday, April 8th, 2023 AT 3:41 PM
Tiny
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Hi,

Wow, that is quite a list. Most of the things listed won't affect the drivability. The C1201 is a little different.

The C1201 is tied into the stability/VSC and traction control. If the engine control system is malfunctioning, VSC and TRAC operations are prohibited, as a fail-safe function. So, the reason those lights are on is likely due to the other codes.

Okay, let's look at this as an evap issue. What has been done to repair the evap issues?

Let me know.

Joe
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Monday, April 10th, 2023 AT 7:19 PM
Tiny
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Hi,

Is there a correlation between the EVAP issue and the VSC codes? The mechanic I had changed the upstream sensor said that now the downstream sensor is bad along with the EVAP cannister. Would it be as simple as just changing the EVAP cannister?

Thanks
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Tuesday, April 11th, 2023 AT 3:08 PM
Tiny
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Hi,

That is very possible. Although the two areas are not directly related, the manual indicates when an engine management issue exists, this can happen. So, they could be indirectly connected.

Let me know if you have other questions. Also, ask your mechanic for his opinion on my theory. It's a bit difficult when the car isn't in front of me. I hope you understand.

Let me know what he tells you and between the three of us, we can make the best educated decision we can.

Take care,

Joe
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Tuesday, April 11th, 2023 AT 8:35 PM

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