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2000 Taurus V6 DOHC. Idles good, runs good but bogs down other times. Shows no OBDII codes. Won't pass smog check because no memory in PCM. Drove it for 2 more days after smog check, still no memory in PCM. Check engine light is off. It is on before engine start, turns off after engine starts. OBDII reader connects and states, no codes to read. This is a well maintained car without any other issues. I'm thinking that maybe the PCM doesn't complete a diagnoses and hangs up. If any one else has had this problem and knows the fix please advise me.
 

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Also certain conditions must be met so tests run. Fuel level between 1/4 and 3/4 and a certain amount of 45 mph cruise so EVAP readiness monitor runs for example. Multiple drive cycles, IE cold to hot and back to cold engine is just one cycle. That's if what jag said checks out.
 

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Is the KAM fuse intact? What does the PCM ground look like?
Thanks for the KAM info. I had no idea what it is or function. Been looking at all the posts so now I know where to start and where I might end up, (Ford Dealer, UGH! ) Thank you, will let you know how this pans out.
 

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Also certain conditions must be met so tests run. Fuel level between 1/4 and 3/4 and a certain amount of 45 mph cruise so EVAP readiness monitor runs for example. Multiple drive cycles, IE cold to hot and back to cold engine is just one cycle. That's if what jag said checks out.
Thanks for the information. Will check it out.
 

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Thanks for the information. Will check it out.
Total program to reset ready for inspection.
OBD-II Monitor Exercised Drive Cycle Procedure

Drive Cycle Preparation. Overnight resting. Check for air temperature as in #3 and gas tank as in #5.

1. Idle vehicle for 15 seconds.

2 Drive at (40 MPH) until ECT is at least (170 F). Engine Coolant..

3. Is Inlet Air Temp within (40 to 100 F)? If not stop here.

HEGO


4. Cruise at (40 MPH) for Up To 4 minutes. Executes the HEGO monitor.

EVAP


5 Cruise at (45 to 65 MPH) for 10 minutes (avoid sharp turns and hills) Gas tank ¼ to ¾ full.

Catalyst


6. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from (25 to 45 MPH) over a 10 minute period. Executes the Catalyst Monitor.

EGR


7. From a stop, accelerate to (45 MPH) at ½ to ¾ throttle. Repeat 3 times. Executes the EGR Monitor.

SEC AIR/CCM


(Engine)

8. Bring the vehicle to a stop. Idle with transmission in drive for 2 minutes. Executes the ISC portion of the CCM.

CCM (Trans Auto)


9. From a stop and in overdrive, moderately accelerate to (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to (40 MPH) cruising for at least 30 seconds. While at (40 MPH), activate overdrive and accelerate to (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 9 five times. Executes the transmission portion of the CCM.

Misfire&Fuel Monitors


10. From a stop, accelerate to (65 MPH). Decelerate at closed throttle until (40 MPH) (no brakes). Repeat this 3 times. Allows learning for the misfire monitor.
 

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Thanks to all for all for the good info on how to fix my problems. I checked all of the fuses and relays under the hood and dash, all checked good. Cleaned and re-attached grounds at battery and two black wires out of PCM. Also ground strap from PCM to engine block. Drained PCM capacitors. Started and drove car as advised in previous posts. Battery showed 12.5 volts engine off. Key on, SES light on. Start engine, light off. The car has had for a long time a "Bump" noise when idling before fully warmed up then went away. Now it is more severe when idling at a stop light all the time. Going from a full stop the transmission shifts normally but when turning a corner it doesn't shift right. Also the engine is a bit slow to accelerate, then speeds up without stepping on the gas. At an idle the engine now feels like it has a very small miss. "Fixed", obdll reader states, no problems. Regular OBDll scanner states no codes reported.
Had a friend with a scanner drive the car and it showed everything good but one Oxygen sensor low output but cleared up after the car warmed up. After reading Haynes manual and watching many utube videos and posts on this site due to when I take the car to be smog tested they tell me there is nothing read so they can't test it. I thought about it and now recall that the "Bump" isn't there when the car is idling and not in drive but in park. I'm thinking that the "Bump" is the Transmission. From what I now understand both of these problems come from the PCM. Speedo normal so VSS should be alright. Trans axle ranger sensor?
Never shows ESL or OBD ll codes. Thanks for all of the helpful advise. Gunnar
 

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Thanks to all for all for the good info on how to fix my problems. I checked all of the fuses and relays under the hood and dash, all checked good. Cleaned and re-attached grounds at battery and two black wires out of PCM. Also ground strap from PCM to engine block. Drained PCM capacitors. Started and drove car as advised in previous posts. Battery showed 12.5 volts engine off. Key on, SES light on. Start engine, light off. The car has had for a long time a "Bump" noise when idling before fully warmed up then went away. Now it is more severe when idling at a stop light all the time. Going from a full stop the transmission shifts normally but when turning a corner it doesn't shift right. Also the engine is a bit slow to accelerate, then speeds up without stepping on the gas. At an idle the engine now feels like it has a very small miss. "Fixed", obdll reader states, no problems. Regular OBDll scanner states no codes reported.
Had a friend with a scanner drive the car and it showed everything good but one Oxygen sensor low output but cleared up after the car warmed up. After reading Haynes manual and watching many utube videos and posts on this site due to when I take the car to be smog tested they tell me there is nothing read so they can't test it. I thought about it and now recall that the "Bump" isn't there when the car is idling and not in drive but in park. I'm thinking that the "Bump" is the Transmission. From what I now understand both of these problems come from the PCM. Speedo normal so VSS should be alright. Trans axle ranger sensor?
Never shows ESL or OBD ll codes. Thanks for all of the helpful advise. Gunnar
Have you used the check engine scanner to clear everything including past codes?
Have you ran some good Fuel System cleaner in it?
Have the intake manifold gaskets ever been replaced? but those usually set of a P0171& 174 code.
Are you due for new plugs and ignition coil?
Is the transmission fluid low? I occasionally get some weird behavior when accelerating and turning left, but I think my transmission is fianlly going out too, since I havent chnaged the fluid in 90k miles and no shop would change it for me in the past either.

I have 293K on my 2000 24V and ive seen alot of random stuff over the years, but your symptom is really strange.
 

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Discussion Starter #9
Have you used the check engine scanner to clear everything including past codes?
Have you ran some good Fuel System cleaner in it?
Have the intake manifold gaskets ever been replaced? but those usually set of a P0171& 174 code.
Are you due for new plugs and ignition coil?
Is the transmission fluid low? I occasionally get some weird behavior when accelerating and turning left, but I think my transmission is fianlly going out too, since I havent chnaged the fluid in 90k miles and no shop would change it for me in the past either.

I have 293K on my 2000 24V and ive seen alot of random stuff over the years, but your symptom is really strange.
Saan, Thank you for your help and good information. I have 186 K on my Taurus SE Wagon, 3.0 V6 DOHC engne. Transmission was rebuilt last year and fluid level is correct. Always change oil filter and Synthetic oil at 5000K intervals. I changed the plugs (platinum ) about 120K. I had a mechanic friend come over and help me check out my problems with his Snap On Ultra Scanner. It was able scan all systems on my car. The "Bump" turned out to be a bad coil on #4 cylinder. Not the transmission. DUH! Changed it and now it idles smooth as a Swiss watch. We checked two of the plugs and they are good and are clean,no brown or black deposits on them. We found a small oil leak coming from the top of the engine so I will change the intake and valve cover gaskets in the next couple of days. The scanner showed bank 2 #2 OX 2 sensor low output. We pulled it and two others we could get to and cleaned them and the low one now has normal output. The scanner now shows evap system problem. After I drained the capacitors And drove it as advised in previous posts it was improved but still not shifting right mainly 1st to 2nd and slow downshift around corners. We took the the car out on a long freeway ride after we scanned and worked on it and the more we drove it the better it ran. When we got back it was shifting almost normally. Starting from a full stop shifted good, turning around corner shifted a little slow but does shift. So the overnight resting and a lot of idling, new coil and O2 sensor online, PCM is maybe okay. When I tried to get it smog tested they said there was nothing to read/scan. The Snap-on scanner read it just fine. I will check it tomorrow with a OBll PO scanner and see what I get. I think my next move is to get the PCM updated with an updated flash memory.
Thanks to all for the help,will let you all know how this project continues.
 
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