First of all, I will like to thank you all. This board has been great to me. I have learned so much about my 6gen and how to do things myself that will cost too much if done by the dealer. Thanks again!

I hope some of you can give me a little help with my first major problem.

My 2000 EX Accord just woke up this morning with his first illness. I notice the “Check Engine Light (CEL)” and after reading trough the forums I performed the DIY instruction to check for the code. On performing the check I notice the CEL came up 5 times, then stop, and then 5 times again and aging… I supposed that the code should be 55 but then when checking for codes I notice there is no 55 just 5. Is this the appropriate CEL light code behavior? Does always the code repeat itself indefinitely when you have the key on?

Anyway, assuming I got the right code (5) “MAP - manifold absolute pressure sensor”. Can I make more damage to the car by continuing driving (at least 5 more days) with this problem? At this moment the car is not presenting any symptoms. The only symptoms I noticed came about 1 month ago when the car (Automatic Trans) at least 1-3 times a week when I stop on signal lights the RPMS goes very slow under 500 I think and the car rattles as if it is going to turn off. But then I pressed a little on the gas pedal and everything goes back to normal (over 750rpm).

My major problem is that the Honda Dealer will no check it until next week. I’m not a technician, but I am very proficient making minor mechanical repairs and maintenance. I have the Helms Manual at home. My car is not on warranty anymore and it has 93K miles with no problem/and repairs bedside maintenance. I check for the MAP sensor and it costs around $80.00 on a parts store near the office. I will be comfortable making the repair on my own since I have worked before on the “Throttle Body” where the sensor is located.

Any other advice?

 

the map should be held on by two screws, simple to change. use a honda part to replace it, it's important in sensor rank. you need a scanner that gives you data list. at idle it should read about a volt or little less. you could backprobe the wires to the map with the engine idling and check it that way, it's a three wire setup. one is ref. voltage, one's voltage to computer(this one should read 1 volt) and one is ground. you should follow the helm manual for sure but if you look up the wiring diagram you should get which wire is which. It's really easy if you follow the flow chart...

It should be cool to drive for now, the computer has a backup mode and it will be fine.

 

Thanks HondaTech,

I will test the volt tomorrow or tonight when I arrive home. Also I will check for lose hoses. Do you think this could be the cause of the low RPM problem?

 

good info.. :thumbup:

 

It's possible it's causing the problem. It could be a bad ground could be anything. The map tells your computer load based on pressure. For fun in the shop me and the guy next to me would "bug" cars we were working on so they ran bad or didn't start. Once the guy next to me took the map sensor off and put a vacuum plug off cap in the hole underneath the map then reinstalled the map. When it started it ran shitty and you could smell how rich it was. I plugged in a factory scan tool, went to data list and looked at map voltage, it was around 4 volts. The computer was thinking it was under a load so it was holding open injectors and dumping fuel. I seen that the map looked ok so I pulled it off and found the cap inside. I reinstalled it without the cap and all was well again. Anyways I thought it was a funny story so I shared.

 

I just checked near by hoses and they seam to be OK. I don’t have a OBD-2 MAP Tool. But the Honda Accord (98-00) Service Manual states that code (5) could be “MAP Sensor Lower than Expected (P1128)” or “Sensor Higher than Expected (P1128)” and to check for MAP failure it requires me the MAP Tool to check for specific parameters. I just called Honda and they told me the will charge $75 to check OBD-2 which will be deducted if I do the job with them; and we don’t have AutoZone here in PR. The part with tem costs $115 and they charge $85/hr with a minimum charge of ˝ hour. So that will bring the total cost to about $160.00 for the repair when I could do it myself for about half the price and learn in the process. I could check the circuit voltage but Honda has another specific code (3) for that problem “MAP Circuit Low Voltage”.

So, is there is any other way to check for MAP Sensor failure. Let’s say by checking the it's resistance between two contacts or by plugging it out and look at it? I don't want to spend $80 bucks for the MAP and the realize it was not the MAP.

On thing I haven't done yet, is trying to "reset" the "ECM" to see if the problem disappears. I have difficult time doing that since it will reset my Alpine radio in which I have spent some time setting radio stations and CD names.

Also this is probably out of topic but… Can you recommend a OBD-2 reader preferably one that I could connect to my laptop/computer. I know the Honda Scan Tool could cost from between 2K (Small) – 7k (Tablet PC Based; and that’s way too much for me. But on the WEB there are so many custom made models ranging from $100 - $300 .

UPDATE: I just "reset" the "ECM" and the CEL is now off. Do you think this could be an intermittent problem? Or maybe after cleaning connections and mount/dismount near by hoses, the problem is solved? If the malfunction occurs again will the CEL light up again or I just fully reset it for that problem?

 

well what that means by lower than expected is that the computer is getting information from the map and it thinks is incorrect based on the on other sensors input. Like the computer knows what map should be for any given condition based off other big sensors like tps, crank sensor. It kinda cross references against the other sensors to make sure nothings out of range. OBD2 cars give more information than the obd1 cars. Obd1 cars would only know a problem existed if the circuit for a sensor was open or shorted. That's it. I've seen obd1 cars with bad O2 sensors that never throw codes.
Obd2 has the same logic above as obd1 plus it has the logic that "knows" when a sensor isn't giving a good input. It knows say that at 50mph and 2300 rpm what the map should be like. It's throwing a code and saying hey that reading isn't making sense then it ignores it and gets a value from a look up table in the computers logic circuit. So, what I said before will give you an answer. You don't need the fancy pants tool, use the tool in your head get a cheapo meter and back probe the connector. If at idle it's like .5v replace it.
Oh yeah and just because it doesn't come right back doesn't mean anything. It probably has a temp. code stored ready to throw on the light if it sees it again. It will most likely come back.

 

Hey HondaTech,

One last question; if I backprobe the wires to the map with the engine idling and it gives me an off set value. Doesn’t that mean that the problem should be between the cables and cars computer?

If I'm not mistaken the sensor does not have a place to test for it voltage other than an OBD-2 reader. I could not found any space to put the probes while the "Sensor" is connected to the cable. Maybe I could get some jumper between the cable that sends voltage back to the computer and the ground cable and test them while connected to the sensor. Is that what you are saying?

Also and finally, what do you mean by a cheapo meter? Can you recommend me one? I think I could pay between $50 and $150 to get one that could give me, at least, the error code and the sensor data the computer sends to the OBD-2. I was reading the “Honda Accord (98-00) Service Manual” and many basic troubleshooting requires some info from the OBD-2. Maybe this could be I good investment on future services to my car as I’m gonna keep it for as long as he can give me the joy.

Thanks for your advice man, I really appreciate it.

 

I think you are getting confused, by meter I mean multimeter. It's a device that measures electrical values. You can get them at sears for less than ten dollars. Harbor frieght has them so does home depot. The best one for automoblies is hands down a Fluke model 88. They run about 400 bucks. But sears has cheapo ones for 10 or less. If you spend like 40 bucks you should get a nice decent one. Fluke's are lab grade type meters, very expensive.
A scanner is a just that they scan for codes. the most basic scanner just scans codes, more advanced(and expensive) ones will give you data list. Which is what the book is calling for. Unless it's a honda scanner which is pricey, it will usually give less information which sucks. I would buy a used MT2500 off ebay if I were you, snap-on has stopped selling them and ppl are all upgrading to the new ones the solus and the modis. If you get one try to get one with all the cords and with as much software possible. For a Honda you need the asian cart. and a "key", make sure it's OBD2 too. Just look through the auctions and buy one with "asian" cart. thats OBD2. It should come with the key. I happened to get lucky and found a used Honda scanner for 100 bucks that was dead. I changed out the batterys( it looks like an expensive pack but if you open the pack it's full of ni-cad rechargeables) and fired it up and it was working cool. I updated it at the dealership and it's now at the lastest software version and ready to go. Plus it has the OBD2 generic function for other cars..If you want a Honda scanner find a used "vetronix" scanner on ebay buy the 8meg card and get someone at a dealer to update it for you and you'll have a honda scanner up to 03. Vetronix makes the 1st honda scanner and it's "mastertech" scanner is the aftermarket version of the honda scanner. The difference is the software. Find a used 8meg honda factory card and you'll be in business. I'm currently looking for a factory card for toyota since yota uses the same scanner still as the old honda one. If I could get one and get it updated through a friend at toyota I'll have one scanner that has factory software for two brand cars that I work on most.
With the factory cards software you get all info plus immoblizer function, etc..
Anyways, check ebay and craigslist in your area you never know what someone has for sell, 100 for a honda scanner almost floored me. I bought it without even looking at it over the phone.

 

Hondatech, you rock!