Titan runs different after ECU reset?

royr · 11-09-2006, 06:43 AM

My service engine soon light came on for no apparent reason just driving along at 45 mph. I reset the ECU with the "easy reset" instructions in the sticky post from this forum. It did not work the 1st 5 times (light did not flash) - but it took on the last try and shut off the service engine soon light. Problem is - now my 2005 CC has lost that "crisp" feeling of the throttle - and my gas milage dropped from 15.4 on average to about 9 mpg. What did I do wrong? What is going on - do I need to rest the ECU a different way - or just keep driving it until she "re-learns" my driving habbits? How long should this take to get my baby back to normal?

gixxer0.6g · 11-09-2006, 07:44 AM

I noticed a slight drop in gas mileage when I reset my ecu but nothing like that. Something doesn't sound right. I'd try resetting it one more time and let it learn your driving again.

baseballfanz · 11-09-2006, 08:32 AM

When you reset the ECU it wipe out all data it's been storing. Driving habits, ect.... that's the reason for lost in milage, give it a few tanks of your regular driving and it will be back to normal.

Marine660 · 11-09-2006, 08:38 AM

I am new here but I don't understand what is meant by "learning your driving habits"...is there some type of fuzzy logic that allows the ECU to somehow "learn" and change the air fuel mapping as you drive?

Black T · 11-09-2006, 08:53 AM

I reset my ECU too and now my passenger air bag light stays off at all time's. What should I do to fix that ? Also I have noticed that my truck doesn't have as much low end throttle than it had before I had reset the ECU..

FtWTitan · 11-09-2006, 10:12 AM

Quote:

Originally Posted by Marine660

I am new here but I don't understand what is meant by "learning your driving habits"...is there some type of fuzzy logic that allows the ECU to somehow "learn" and change the air fuel mapping as you drive?

I personally don't think it has to do with "driving habits." It does use a closed loop system to achieve ideal combustion, and that is what helps with fuel economy and performance. So it is a fuzzy logic system in that it takes data from the various sensors and says "If this, then do this." I don't know for sure, but I imagine the ECU uses arrays of data that are constantly being overwritten to average out the air/fuel mix/timing/etc. Either way, it shouldn't take too long for it to average out to it's former settings, assuming you haven't changed any components on the truck since then.

Royr, how long has it been since you reset it? I would think it would take at least a couple hundred miles to get back to normal. I'd like to reset mine since I added the exhaust, but not sure it would affect it much.

royr · 11-09-2006, 11:18 AM

[quote=FtWTitan]
Royr, how long has it been since you reset it?

Have driven about 90 miles since I reset the ECU late last night - and filled the tank - do you really think it takes a couple of hundred miles to give me back what I am used to?

SoBeGraphics · 11-09-2006, 11:36 AM

First off you are not addressing the original catalyst to the problem which is your check engine light. They do not come on for no reason. You have a problem and i would recommend taking it to the dealer to have it checked asap. The ecu rest wipes out all the data so the problem you have stillexists but the ecu has to re-learn about your problem. The ecu will and can adjust timing and af due to temp and altitude and driving habits. I have learned that you should NOT do an ecu reset as your ecu will lose valuable info (kudos to Shailey). For ex. if your ecu has found that your engine is progressivly over time getting leaner and leaner it may throw a check engine light so a tech can look into why the engine is becoming leaner. Since you reset the ecu the light is gone because you wiped out the history of the ecu but not the problem that caused it.

Get her to the dealer - especially after the ecu reset you are still having problems.

Burly · 11-09-2006, 12:18 PM

Quote:

Originally Posted by SoBeGraphics

First off you are not addressing the original catalyst to the problem which is your check engine light. They do not come on for no reason. You have a problem and i would recommend taking it to the dealer to have it checked asap. The ecu rest wipes out all the data so the problem you have stillexists but the ecu has to re-learn about your problem. The ecu will and can adjust timing and af due to temp and altitude and driving habits. I have learned that you should NOT do an ecu reset as your ecu will lose valuable info (kudos to Shailey). For ex. if your ecu has found that your engine is progressivly over time getting leaner and leaner it may throw a check engine light so a tech can look into why the engine is becoming leaner. Since you reset the ecu the light is gone because you wiped out the history of the ecu but not the problem that caused it.

Get her to the dealer - especially after the ecu reset you are still having problems.

Well said

Marine660 · 11-09-2006, 12:23 PM

You can take any vehicle to AutoZone or Advanced Auto and they will read the error number that caused the check engine light. They then look up the error code and can tell you if it was an O2 sensor, faulty spark plugs, timing, etc....

Best thing is that its free! I had the check engine light come on with my Dodge Ram and after going to autozone they told me that I had a faulty gas cap?!?!? I went out and sure enough I had cross threaded the gas cap letting air into the tank. I took off the cap and put it back on, the autozone guy reset the ECU for me and no more problems...

It could be something this simple and I would hate for someone to waste 3 hours of their lifes waiting in a car dealership if you don't have to.

Marine660 · 11-09-2006, 12:28 PM

As for the "fuzzy logic" comment above, I agree that it can use a small data set (array of numbers) to look for things such as abnormailities and can also make sure that your numbers are within tollarnce. If they are not, then you will get a check engine light.

So, we are in agreement, however, I don't think that it can store hundreds of miles worth of data...

For example, when you purcahse the truck it has zero miles and therefore zero data. I don't think that the first 100 or more miles the truck feels sluggish or unresponsive as some have posted after doing the reset. I would dare to say that this "fuzzy logic" looks maybe at the last 2-3 minutes of drive time and then overrights the data. It is storing large amounts of data (Air/Fuel mixture, Throttle position, temps, timing, O2 levels, speed, etc...)

I guess we don't really know so we are disscussing a mude point.

BTW, thank you for this great forum, I have been snooping for a little over a month and am about to purchase a 2007 CC LE using the friends and family plan.

SoBeGraphics · 11-09-2006, 12:29 PM

Wow... as Johnny Carson would say... "I did not know that" A check engine light came on in my wife Galant - we took it to the dealer and the dealer asked if she had forgotton to cap the gas tank. She said yes and they reset the light. Problem resolved except the dealer got me for $45.00!!!

SoBeGraphics · 11-09-2006, 12:36 PM

Quote:

Originally Posted by Marine660

As for the "fuzzy logic" comment above, I agree that it can use a small data set (array of numbers) to look for things such as abnormailities and can also make sure that your numbers are within tollarnce. If they are not, then you will get a check engine light.

So, we are in agreement, however, I don't think that it can store hundreds of miles worth of data...

For example, when you purcahse the truck it has zero miles and therefore zero data. I don't think that the first 100 or more miles the truck feels sluggish or unresponsive as some have posted after doing the reset. I would dare to say that this "fuzzy logic" looks maybe at the last 2-3 minutes of drive time and then overrights the data. It is storing large amounts of data (Air/Fuel mixture, Throttle position, temps, timing, O2 levels, speed, etc...)

I guess we don't really know so we are disscussing a mude point.

BTW, thank you for this great forum, I have been snooping for a little over a month and am about to purchase a 2007 CC LE using the friends and family plan.

Marine welcome to the club and yes the nissan does log a lot of data. The ecu also has a break in mode that people on this forum have found it to baby the truck until it reaches it's break in period. I believe that the 06 now even come with a "black box" that records everything. Surf around this site you will learn SOO much about the Titan. Here's one... did you know if you hold down the key FOB unlock that it will roll down your windows? Cool huh. READ ON and SEARCH IS YOUR FRIEND!!!!