LexHelp

So I have a few question for you guys and I'll ask them one by one in this thread rather than having several. Thanks in advance.

1. I bought this ES and literally drove it off the lot and in less than a mile the check engine light popped on. What are the odds that this was coincidence vs. the stealership clearing the code just to sell it? I'm protected in SC by lemon laws and honestly I overpaid on this car although it drives fine. I was in a jam and needed wheels asap. I typically only buy from real owners so I get an actual idea of what I'm buying.

2. Am I understanding correctly that the Computer on these cars is so crude that one sensor mis sets off many?

My VSC Off light is on as well as my VSC light and Check engine light. The codes it throws follow.

P0171 system too lean bank 1
P0125 insufficient coolant temp
P1135 airflow
P1155 airflow
P1133 airflow
P1135 airflow
P1153 airflow
P1155 airflow

lostape45

What year is the car? You have to provide us with more details on the car to help out. They very well may have cleared the codes to sell it to you, sneaky stuff. As for the computer, it may or may not set off other codes, depending on what sensor is tripping the CEL. Usually all of the codes listed are in relation to each other and pop up for a reason.

LexHelp

I apologize its a 99 ES300.

ES300NZ

The 1999 computer is not crude, it's rather intelligent actually. It's OBD2 for a start.

Those codes are for the MAF sensor. I'd guess the sensor was stuffed, or damaged by cleaning products. It will need a replacement sensor, either new or used would be fine.

P0125 insufficient coolant temp: = this one bothers me. Perhaps someone else can shed some light on it. I view it as the ECU thinks the sensor is either not plugged in, or not functioning. OR the Ecu thinks the two pin sensor is not up to temperature yet, which makes no sense for the ecu to throw a code for, and Toyota ecu's aren't stupid so they don't throw codes for things like that.

LexHelp

Can you please be more descriptive, I said crude because I read elsewhere one wrong thing would throw off many. I many how the hell can an MAF cause VSC to turn off?

What codes exactly are for the MAF? Should I start there, reset it after replacing and run the computer again to see what goes away?

P0125 doesn't make sense either as the thermostat stays put regardless of how long I let the car just sit and idle. And the rad fans kick on as they should.

ES300NZ

They aren't related. It's two separate issues being detected, from two seperate systems which are controlled / monitored by the same computer (I think).

yeah I would, reset by removing batt terminal. Or not, codes do clear when the problem resolves.

thermostat ? temp gauge .. I guess. that's a separate sensor (single pin). Radiator fans kick in on a seperate sensor again (fan switch, lower right of radiator). The two pin ecu temp sensor which is the third sensor in this sensor orgy, .. forms part of the fuel calculations, if it's faulty (which is rare but not impossible) then being too rich or too lean is entirely likely.

wise2k

I think the VSC function is designed to work on a perfectly working engine due to its complexity and functionality, such that if there is fault (CEL), the engineers rather have the VSC system shut off than risk having the engine underperform when needed in a case of emergency (that way you kinda know that you are on your own than think you'll get help from the VSC system but find out its perfomance was insufficient due to the issues your car is having).
That being said, your VSC is (more than likely) okay, just disabled until you bring the engine back to optimal performance condition.

Below is some background information on VSC from Toyota, and note the necessity to adjust engine power on-demand (http://www.toyota-global.com/innovat...ctive/vsc.html).

Vehicle Stability Control (VSC)
Helps prevent wheels from slipping sideways when cornering or sudden steering

VSC is a system that helps prevent side skids and help stabilize the vehicle while turning on a curve. According to the National Highway Traffic Safety Administration's (NHTSA) report, vehicles equipped with VSC compared to those without can effectively reduce single-vehicle accidents by 35% for automobiles and 67% for Sport Utility Vehicles (SUV).

When the vehicle senses a loss of traction or a slip, braking is automatically applied to all 4 individual wheels and engine power is reduced to help secure the safety of the vehicle. For example, if the steering wheel refuses to turn from over-speeding (under-steering), the vehicle will take control to steer toward the inner curve. Also, when the vehicle begins to spin from abrupt steering handling (over-steering), the vehicle will take control to steer toward the outer curve.

*VSC is designed to help the driver maintain vehicle control, and it is not a substitute for safe driving practices. Also, the system will not be able to surpass the performance of the quality of the tires.