2002 Explorer codes?

A scan tool is required.... Some auto parts outlets will scan for codes for free. They will try to sell parts to you.... avoid this urge and post the exact code(s) retrieved back here. someone will apply common sense to your concern and do their best to keep you from spending money needlessly.

Thank you SO much.

I'm a little worried, though, because it's about 25 miles to the nearest auto parts store and I won't be able to get there until after work tomorrow. That means a two-mile trip to work, a two-mile trip home, a 25 mile trip to the store, and then a 25 mile trip back to post so that y'all can help me figure out what's wrong . . .

Is that o.k.? I mean, it's just the "service engine soon" light, not the "your vehicle is about to explode" light, but . . . ???

Starting in model year 1996, any vehicle sold in the US (and some other countries) is 'OBD2' compliant. This, unfortunately means that you need to access the computer in your vehicle with a scanner or at least an 'OBD2 code reader' to retrieve trouble codes. Simple code readers are sold in auto stores for perhaps as low as $100 (make sure that your vehicle is listed if you are buying one). Also, the Autozone chain is known to read codes as a free service (perhaps except in California). The real problem, though, is not how to read the codes, but what to do next. The codes by themselves give some clues, but don't trust anyone who tells you "if it's such and such number, than you have to replace such and such part". One exception, which is most likely in your user manual: the code for 'gross evaporative leak' (don't remember the number off the top of my head) means that gasoline vapors are escaping from the tank. The most common reason is simply forgetting to tighten the gas cap after refueling. So before you spend the big bucks, make sure that your gas cap is in good shape and screwed on tightly. If that was the problem, the light will go out on its own after a few drive cycles.

And by the way: no, the check engine light does not turn on just because it's been so many miles since the last oil change. There is a real problem that you need to address.

Thank you very much for your response. I've re-tightened my gas cap, but I haven't refueled in several days.

I was SO hoping it was something simple, like an oil change . . . I mean, "service engine soon"? I don't know what else to do for it, other than take it some tea or something . . .

If there aren't any major running concerns you "should" be OK.... There's a lot of people out there that continue to drive for months before having things attended to (not something particualarly good for the environment or vehicle). Better to have the concern "researched" (if one can call AutoZone research) than to just continue operating the vehicle.

Kristy,

If the light is on constantly, it's probably not a serious problem. If the light is blinking, then it's more serious. At least that's what the book for my 98 Explorer says.

If the problem was the gas cap, you need to drive the car 3 times for at least half an hour each time ( it's thoroughly warmed up by then), then the light should go out.

I'm a gadget guy 8*) When my check engine light recently came on, I picked up a scan tool for less than 50 bucks on Ebay, it was really easy to use and I was able to read and then erase the code, and the warning light has been off ever since. If the problem persists, the light will come right back on immediately.

Good luck!

Red

I'm in the middle of this problem myself on my 2002 V-8. Like a good boy, I took the vehicle to a dealer, 35 miles away, who of course couldn't trouble-shoot it on the spot so my wife had to come along in a second car to get me home. Dealer called me next day, said that the code was something like P041 = BAD DPFE SENSOR, so they replaced the sensor. I drove up the next day (again witrh my wife and a second car), retrieved the vehicle, drove it home - and the light came on again the next day.

Called the dealer, they said they might have gotten a "bad sensor", so I had to bring it back and leave it - again using a second car. Next day, the dealer called, "Yup, bad sensor, so we replaced it again at no cost to you." So I drove up again, again in my second car, and retrived the vehicle. Got it home, and guess what? Next day the light came on again. They want me to bring it back again.

I'm losing faith. But I'm in for over $100, not counting gas for all those extra trips - and with gas a $3+ a gallon, that adds up. And of course the dealer isn't simply going to hand that back money to me.

There are at least two lessons here. First, as someone noted, simply reading the code doesn't tell you what to do. Second, doing your "research" at AutoZone isn't necessarily worse than paying your dealer to do it.

Bill

Jim may disagree, but in many cases the owner's troubleshooting could be more effective than the dealer's. Our tools are not be as sophisticated, but it's our vehicle... And the owner can typically afford to spend 'as long as it takes', while the dealer's mechanic has a book telling him how long he is supposed to spend on any given task, and six more cars waiting for his attention. Not to mention a boss...

P0401 does not mean 'Bad DPFE'. It stands for 'Insufficient EGR Flow'. The manual lists 17 (!) possible causes for that code to turn up. Even if they did sloppy troubleshooting work and unnecessarily replaced a part, it's still totally irresponsible to send you home without even checking that the problem was fixed. Or, they might have fixed the P0401 and ignored additional codes. Nobody said that you only have one problem. Perhaps they assumed that the reason your CEL is back on is the old P0401, and neglected to rescan... over and over again.

One way or another, it's time to move to the independent across the street -- troubleshooting an EGR system is not rocket science! A letter to the dealership's general manager, explaining where you are going to buy and service your next vehicle couldn't hurt either. What makes the economy going (assuming that you live in some western democracy) is competition.

Or, if you are so inclined, spend a few bucks on books and basic tools, invest some time, and do it yourself. You will be amazed how much you learn in the process.

Good Luck

O.K., I finally have both the codes from the kind people at Autozone AND my internet working . . .

Two codes showed up: P1400 and P1405.

The best they could tell me was that it had something to do with the emissions system, but that it's vehicle-specific.

????

Thanks for your help!

Dick

Hi Can you help, I am in the Uk and have a 1998 Explorer 65000mls the light is on and i am looking for the engine management module and the OBD2 test plug for the codes. Can you tell me were they are.

Thanks Dick

Just found out what the codes mean:

P1400 - Differential Pressure Feedback Electronic Sensor circuit Low Voltage P1405 - Differential Pressure Feedback Electronic Sensor circuit Upstream Hose

Now . . . anyone able to tell me what the heck THAT means?

These codes are related to the EGR (Exhaust Gas Recirculation) system. Like much everything else, this system is computer controlled. The DPFE sensor monitors the amount of EGR flow by measuring the pressure difference across a restriction. P1400 means that the voltage out of the sensor is below its expected range. P1405 indicates that the computer 'thinks' that the upstream connection of the sensor is broken or plugged. There are many possible reasons for these codes, but most people on this NG will agree that in 90% of the cases the sensor itself is defective. It's a very common failure. So if you like to gamble, replace the sensor. It's a quick and simple task, requiring not much more than a 8mm (or perhaps 6 mm - don't remember) socket and nimble fingers. But before you blow the 50-75 bucks on a new sensor, make sure that the tubes leading to it are in place, not plugged with carbon and not crossed (has anybody worked on this vehicle before?). The sensor is a grey or black box, about 3x3x1 inches, with an electrical connector and two nipples. It's somewhere near the rear of your engine. Or get a decent manual, a handheld vacuum pump and a voltmeter (a scanner is nice, but not essential) and properly diagnose the system May not be cheaper than the shotgun approach, but you will learn a lot.

Good Luck

The OBD2 connector is on the bottom of the control panel, somewhere near your left knee (in the US, but go figure what happens when the wheel moves to the right...). Typically behind a little access cover that just pops out. You will need a scanner or an OBD2-capable code reader to make any use of it.

Not sure why you think that you need to access the PCM. It rarely fails and 'no user serviceable parts inside'. Look for a large black rectangular connector with a center bolt on the firewall, perhaps a bit towards the passenger side (or is it the driver side in the UK?). If you intend to troubleshoot anything by probing the harness, be very careful not to damage the contacts, and even more careful not to bend the PCM pins when reinstalling the connector. It's very easy to plug it in cocked and create havoc when tightening the bolt.

Oh, one more thing: before you venture too far, make sure that your gas cap is tight. A loose gas cap is a common cause for the CEL to turn on and the easiest $75 (how much is that in pounds?) your dealer ever made.

I'm > These codes are related to the EGR (Exhaust Gas Recirculation) system. Like