Check engine light ON/OFF

[mchell]

My check engine light goes on for about a week then just shuts off.Any idea of what that could be from????????

[Chris92SE]

The SES light comes on when there is a problem and the code for that problem is stored in the ECU.

You will need to plug it into some kind of code reader. If you don't know someone that has one, some parts stores will check it for free.

I bought a code reader off of ebay for around $40 a couple of years ago. It was some of the best money I ever spent. I use it on friends' vehicles, as well as my own.

In the stickies there is a list of what all of the codes are.

[Buzzman]

I bought a code reader off of e-bay for around $40 a couple of years ago. It was some of the best money I ever spent.

I did the same thing a few years ago, only I got mine on sale at Canadian Tire.Have to agree that it was money well spent.If the SES light is on, it's pretty much impossible to start troubleshooting without the codes. That's the first thing to do. Good luck.(It would also help if you tell us what you are driving, what year, etc.)
Modified by Buzzman at 6:15 PM 1/23/2009

[coledog188]

Mine sometimes does the same thing...it says my knock sensor is bad. If it comes on, it's when I'm low on gas.

[mchell]

I have an '03 pathfinder SE 4X4. I have had my sensor replaced already, the only time that light went on was for low oil (Nissan was so nice as to give up on my oil leaks) and resets itself when I get an oil change and it's full. But after my oil change the light goes on and off for about a week at a time. STRANGE......

What is the tool used to get the readings? And I did print out the codes thanks!

[fukkeneh240]

I did the same thing a few years ago, only I got mine on sale at Canadian Tire.Have to agree that it was money well spent.

are these code readers car specific or universal?

[rhd itr]

[QUOTE=mchell]My check engine light goes on for about a week then just shuts off.Any idea of what that could be from????????[/QUOTE

its a reaccuring thing with some pathfinders. Mine does it, along with my brothers, and everyone else i know that has one. The only bad part is, you cant tell if its on for a reason or not. Usually its just on for no reason. I read somewhere that its just an electronical malfunction

[Chuck Tribolet]

For '97 (I think) and later, and a few just before that, they are OBD-II standard.Before that, they were OBD-I standard. Before that, they were unique, andbefore that, they didn't exist.

Since the OP has an '03, it's OBD-II.

rhd itr: If the SES light comes on, it's for a reason. Read out the codes andfnd out what's going on.

[rhd itr]

i

For '97 (I think) and later, and a few just before that, they are OBD-II standard.Before that, they were OBD-I standard. Before that, they were unique, andbefore that, they didn't exist.

Since the OP has an '03, it's OBD-II.

rhd itr: If the SES light comes on, it's for a reason. Read out the codes andfnd out what's going on.

I disagree because i ran a code on my ecu and nothing came up. Also we took my brothers down to schucks and ran a code, suprisingly nothing came up. hmm what a coinsidence. So then i went to my local auto specialist that specializes in nissans and he told me that its a reacouring thing with some pathfinders, and some times its due to a electrical malfunction. Im just saying, go to schucks and run a code

[Buzzman]

For '97 (I think) and later, and a few just before that, they are OBD-II standard.Before that, they were OBD-I standard. Before that, they were unique, andbefore that, they didn't exist.

You're right. I'm 99% sure that anything after '96 is OBD-II compliant.The interface is standard on most makes and models, or should be.The code reader I bought is a pretty basic unit, but it does a good job.The only thing it doesn't work on are diesels.

[ganesh21]

i have '01 pathfinder. Vehicle mileage: 86400+ miles

The check engine light come on and stay on for a while then come off. I am waiting for it to get a little warmer to do some troubleshooting. Currently in the 20F in NYC.

Also, my ABS and 4WD drive come on. If i re-start the vehicle, the light come off. I check and both my ABS and 4WD work fine.

[Chris92SE]

i have '01 pathfinder. Vehicle mileage: 86400+ miles

The check engine light come on and stay on for a while then come off. I am waiting for it to get a little warmer to do some troubleshooting. Currently in the 20F in NYC.

Also, my ABS and 4WD drive come on. If i re-start the vehicle, the light come off. I check and both my ABS and 4WD work fine.

Mine did that (ABS and 4WD light) and about a week later my alternator conked out.

I kind of figured that was the problem, though. It didn't have any codes and the electrical system wasn't getting enough power. Right before it finally conked out, the gauges went totally buggy.

[ganesh21]

Mine did that (ABS and 4WD light) and about a week later my alternator conked out.

I kind of figured that was the problem, though. It didn't have any codes and the electrical system wasn't getting enough power. Right before it finally conked out, the gauges went totally buggy.

My alternator is fine. I will be replacing it spring. Plan on getting a 200+ amp.

I will check out why it come on and off. Just got the let the cold weather past.

[rubyzero]

If you have an AutoZone store, they will read the code for free. Probably somthing with emissions controls.

[keelhaul]

How to Switch Diagnostic Test Mode(check codes without reader)

NOTE:It is better to count the time accurately with a clock.It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit has a malfunction.

How to Set Diagnostic Test Mode II (Self-diagnostic Results)1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.2. Repeat the following procedure quickly five times within 5 seconds.1) Fully depress the accelerator pedal.2) Fully release the accelerator pedal.3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the MIL startsblinking.4. Fully release the accelerator pedal.ECM has entered to Diagnostic Test Mode II (Self-diagnostic results).

A particular trouble code can be identified by the number of four-digit numeral flashes. The “zero” is indicatedby the number of ten flashes. The length of time the 1,000th-digit numeral flashes on and off is 1.2 secondsconsisting of an ON (0.6-second) - OFF (0.6-second) cycle.The 100th-digit numeral and lower digit numerals consist of a 0.3-second ON and 0.3-second OFF cycle.A change from one digit numeral to another occurs at an interval of 1.0-second OFF. In other words, the laternumeral appears on the display 1.3 seconds after the former numeral has disappeared.A change from one trouble code to another occurs at an interval of 1.8-second OFF.In this way, all the detected malfunctions are classified by their DTC numbers. The DTC “0000” refers to nomalfunction.

first digit -slow flashes ;next digit- faster flashes ;next digit-even faster10 flashes= 0

How to Erase Diagnostic Test Mode II (Self-diagnostic Results)1. while ECM is in Diagnostic Test Mode II (Self-diagnostic results). .2. Fully depress the accelerator pedal and keep it for more than 10 seconds. The emission-related diagnosticinformation will be erased from the backup memory in the ECM.3. Fully release the accelerator pedal, and confirm the DTC 0000 is displayed.

Modified by keelhaul at 5:28 PM 2/3/2009
Modified by keelhaul at 5:35 PM 2/3/2009

[jetroy240]

It will be easier for everybody what the code is, since u said u print out the code?

[Chuck Tribolet]

The SES light comes on when the ECU detects a repeated problem (before thatit can be read out as a "possible" problem) and gets turned off when theproblem hasn't occurred for a while. IIRC, it gets turned on if the problem occurson two consecutive "drive cycles", and goes out if it hasn't occured for fiveconsecutive "drive cycles".

One thing that can be really helpful is that it logs how many miles since theevent that turned on the light. That was REALLY helpful to me. I put my route that day into MS Streets and Trips (backwards from where I readout the code) and it showed me exactly where the problem happened (whichwas several miles from where I'd guessed based on the distance). Thattold me what triggered it (long medium uphill).

So what's a "drive cycle". I'd love to know. The story that makes the mostsense is "engine cold to engine hot and back to engine cold".

But, net: you got an intermittent problem. Get the codes read out while thelight's on.

I can remember when there were NO computers in my '72 240Z. All debugginghad to be done after the fact. (And 155 HP in a slippery body got aboutthe same gas mileage as 250 HP in big boxy '01 PF. Computers are good.)

[jetroy240]

Well if the SES light came on & off, most of the time,it will store a code, even the SES light is off. For 2003 Pathfinder, I would use the Generic scan tool for obd II w/c uses the universal diagnostic connector, assuming u don't have access to a Consult II scan tool for Nissan. If it did not store a code, can't do anything until light came back & store a code.

It's true that some year model, you will get nothing if u hookup to the wrong diagnostic connector. At the dealer, beginning 2000 & up, u have to use the universaL 16 pin diagnostic connector, & 1999 & below, u use the gray diagnostic connector & checker box for older cars & self-diagnostic at ecu if available for w/o scan tool .
Modified by jetroy240 at 11:16 PM 2/5/2009

[drew97qx4]

same as above post here.

[Almatti]

It's probably the o2 Sensors. The PFs in these year models are Notorious for it. Make sure you really tighten that gas cap when U fill up. My local mechanic told me that it is from the added Ethanol to the gas. My 01 PF has the same problem. I've reset the ECU by disconnecting the battery for a while, added some STP fuel injector cleaner toa Full tank of Premium gas, and viola', the CEL stays off for months. But that gas cap thing is in the manual for a number of other Japanese cars: Subbies, Nissan, etc. Also "im in the NYC suburbs, Ethanol added in the gas for "winter" blends can be up to 15%, that will REDUCE MPGs too....

[pathfinder97]

I have the same issue. 3 codes came up when i ran them. 2 evapretive emmision codes? and the knock sensor code. i am due for an oil change but not clear on how that effects the knock sensor. any word?

[coledog188]

Well, the check engine light went back off for about 2 months...came back on last week. Probably the same code, but thanks for the Diagnostics Test entry! I'll give it a shot.