check engine light on but no codes
#1
05-04-2009 | 06:39 PM
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Junior Member
Joined: May 2009
Posts: 1
check engine light on but no codes
my wifes car is an 03 2.0 auto protege. a few weeks ago it sounded like it had a miss and the cel came on. took it to autozone, they scanned it, and said it had a no. 4 cylinder misfire. ok. got new plugs and wires for it and put them on (electrode on no 4 plug was nearly gone) car started up and ran great. the next day the cel went out on its own. yesterday the cel came back on, took it to autozone, dude plugged in the scanner and nothing, it didnt even power on. he went in and got a new one - same thing, wont even power on. took the car to advance auto, same thing-wont even turn on. took the car to an independant shop-same thing-no juice.
has anyone else had this/similar problem?
i read elsewhere to check for power at the #4 & #16 ports on the obd2 (can) plug. at #16 i get 12.9v, at #4 i get 0.00v. the wire going to #4 is black, is this a ground? if your car powers the code scanner you plug in to it, something needs to be grounded? right?
i checked all fuses-ok, all accessories work.
i did notice that the cooling fan doesn't come on very often, if at all. after driving around for an hour today in 85 degree heat, i had to sit in my driveway with the engine tached up to 3000 for 5 minutes to get the fan to come on. then it was only on for a few minutes. i also read elsewhere that a sticking thermostat could create an open loop in the ecm ...blah,blah,blah and that may not allow a code scanner to power up???
anyone have any ideas????
has anyone else had this/similar problem?
i read elsewhere to check for power at the #4 & #16 ports on the obd2 (can) plug. at #16 i get 12.9v, at #4 i get 0.00v. the wire going to #4 is black, is this a ground? if your car powers the code scanner you plug in to it, something needs to be grounded? right?
i checked all fuses-ok, all accessories work.
i did notice that the cooling fan doesn't come on very often, if at all. after driving around for an hour today in 85 degree heat, i had to sit in my driveway with the engine tached up to 3000 for 5 minutes to get the fan to come on. then it was only on for a few minutes. i also read elsewhere that a sticking thermostat could create an open loop in the ecm ...blah,blah,blah and that may not allow a code scanner to power up???
anyone have any ideas????
#2
05-05-2009 | 04:11 AM
Senior Member
Joined: Sep 2008
Posts: 292
when you checked the # 4 and 16 ports did you have your key in the accesory position? because that power going into that obd2 port is what powers the scantool. But i honestly don't see how an open thermostat housing could be the reason why your not able to read codes.
#3
05-09-2009 | 10:46 AM
Senior Member
Joined: Mar 2009
Posts: 466
It's got to be electrical: from the description of your plugs, your car's electrics don't get too much TLC. Just because you've got enough juice to power the voltmeter doesn't mean there's enough to power up the OBD reader.
Go to the battery, make sure the terminals are clean and tight. Next, follow the short ground cable going from the battery -ve to chassis, near the windshield wiper motor. With the battery negative disconnected, loosen and clean up the 3 bolts, and the grounding plate. The 10 or so wires that fan out from that grounding plate are vital to proper working of the car's electronics and sensors.
While you're at it, go over to the passenger side and look for a fat wire connected to engine ground via one of the engine mounts, and clean that up too.
If you've checked out all your fuses by pulling them and checking for continuity (both the engine compartment ones and the ones inside near the driver's door, then the problem is most likely to be the ignition switch or its connector. You can try cleaning them both with contact cleaner, and also, if mechanical wear is the issue, try using your spare key; this can be a temporarily fix.
The cooling fan issue you should ignore for now. Given the state of your ignition, your ECU would have put your timing all over the place, so your car was taking gas from the tank, putting some of on the road through the wheels, and wasting the rest through radiator heat, catalytic converter cooking, or exhaust gas hydrocarbons.
With ignition fixed, you can get more road power with less dissipated power.
This being so, your car will deliver the same performance with less waste heat, hence less fan on time.
Finally, the way you tested the fan cut in is not the way to do it. With your engine unloaded at 3000 rpm, your water pump would be pushing so much coolant through the radiator, I'm surprised your fan cut in at all; in fact what you did is sound practice for cooling down an overheated engine.
The way to check fan cut in is to work the hell out of the engine under load, and then either let it idle, or on many cars, just turn it off. The heat from the workout takes time to percolate through the cooling system, and with next to no water pump activity, the engine temperature will rise quite quickly, causing the fan to cut in.
Another point, when the cel was on at first, was it solid on or blinking, and how long were you driving around with a blinking cel (which indicates an engine misfire status, and should be dealt with ASAP) ?
Keep us up to date on your findings.
Go to the battery, make sure the terminals are clean and tight. Next, follow the short ground cable going from the battery -ve to chassis, near the windshield wiper motor. With the battery negative disconnected, loosen and clean up the 3 bolts, and the grounding plate. The 10 or so wires that fan out from that grounding plate are vital to proper working of the car's electronics and sensors.
While you're at it, go over to the passenger side and look for a fat wire connected to engine ground via one of the engine mounts, and clean that up too.
If you've checked out all your fuses by pulling them and checking for continuity (both the engine compartment ones and the ones inside near the driver's door, then the problem is most likely to be the ignition switch or its connector. You can try cleaning them both with contact cleaner, and also, if mechanical wear is the issue, try using your spare key; this can be a temporarily fix.
The cooling fan issue you should ignore for now. Given the state of your ignition, your ECU would have put your timing all over the place, so your car was taking gas from the tank, putting some of on the road through the wheels, and wasting the rest through radiator heat, catalytic converter cooking, or exhaust gas hydrocarbons.
With ignition fixed, you can get more road power with less dissipated power.
This being so, your car will deliver the same performance with less waste heat, hence less fan on time.
Finally, the way you tested the fan cut in is not the way to do it. With your engine unloaded at 3000 rpm, your water pump would be pushing so much coolant through the radiator, I'm surprised your fan cut in at all; in fact what you did is sound practice for cooling down an overheated engine.
The way to check fan cut in is to work the hell out of the engine under load, and then either let it idle, or on many cars, just turn it off. The heat from the workout takes time to percolate through the cooling system, and with next to no water pump activity, the engine temperature will rise quite quickly, causing the fan to cut in.
Another point, when the cel was on at first, was it solid on or blinking, and how long were you driving around with a blinking cel (which indicates an engine misfire status, and should be dealt with ASAP) ?
Keep us up to date on your findings.
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