Once again Im having problems with my 2000 mazda millenia. The engine tach works, but when you put it in gear it stumbles and dies. If your are lucky and feather the throttle just right (1/4 thottle) you can drive it. The motor will even rev up to 5000 rpms without a miss, but when it idles to long, it stumbles and dies. Along with the TCS light coming on I pulled a P0725 code which is some kind of speed sensor on the trans. This code will be set by TCM if RPM signal is below 470rpm for at least two seconds with vehicle speed greater than 25 mph. but i dont know where to look. any help would be greatly appreciated.

 

Along with the P0725 code the scanner also showed the FUEL TRIMS as STFT1/LTFT1@ 0%, STFT2/LTFT2@0%, STFT3/LTFT3@-100%, STFT4/LTFT4@-100%.Problem accured at 32 mph, showed 0 rpm's, 190 coolant temp, map sensor was 99kpa, under 87% engine load. The engine Tach works and the motor will even rev up and redline if a person wanted to, but when it comes back down to idle it will kinda stumble from time to time and die especially when pulled into gear. I can only drive when I feather the throttle and not go past about 1/4 throttle. I havent checked the cranksensor yet, but could it be the trans control module and where would it be located and how can I check it? I appreciate all your time and help and if at all possilble can you post the info you sent me in my post (p0725 code) to help other Millenia owners if they would happen to have the same problem. Thanks and I will get back with you!

 

From: babyhuey
To: 2000smazda
Date: 7/17/2006 7:59:11 PM
Subject: RE: P0725 code

Hi again Scott. Just one thing after another isn't it. That's the way it goes sometimes I guess. Does the tach on the dash work??
P0725 is an indication that the Tranmission Control Module has lost an engine rpm speed or tach signal. This rpm signal is provided to the PCM by the Crankshaft Position sensor. The PCM then sends this signal out to the TCM and the Instrument Cluster.
Kind of odd that you would not also get a P0335 which is the PCM telling you that it has lost signal from crank sensor signal instead of only the P0725 from the TCM.
Guess I would start off by taking a look at the crank position sensor. It is located on the front lower engine area right next to the crankshaft pulley. The connector for it is at top of the engine kind of straight up from the sensor. Two wires in the connector, one is Green and the other is Blue in color. Make sure is plugged in first and connector not damaged. Disconnect and you can check resistance across the sensor. Drawing below is of the sensor and which wires to check. Should have a resistance between 950 and 1250 ohms. If that checks out ok then you will want to check the air gap between the sensor tip and the little teeth on the outer edge of the crankshaft pulley. Will have to send that drawing in a separate PM as you can only download one at a time.


Thumbnail Image


millenia ckp ohm.gif

 

From: babyhuey
To: 2000smazda
Date: 7/17/2006 8:00:28 PM
Subject: RE: P0725 code

Here is the air gap drawing. Specification is .5 to 1.5 millimeters or .020-.050 inches.


Thumbnail Image


millenia ckp air gap.gif

 

I checked the air gap on the crank sensor and its ok ,and it had 1141 ohms. I did clean some crudd off of it, then started it up while on the jack stands, and when I put in reverse it stuttered and the TCS light started blinking then it died. What can I do now? I'd pull my hair out but I don't have any!

 

Here are the drawings that were supposed to go with the above posts with checking resistance and air gap.
The TCS light probably started flashing because the Traction Control System was seeing massive front wheel slippage with no rear wheel movement. That part would be fairly normal to happen. Stalling no.
What dash light being on prompted you to check for codes by the way. You noted TCS but the HOLD light should have been the one that started flashing when RPM signal was lost. The RPM signal was obviously lost for at least some period of time as your scanner showed RPM freeze data at zero. Code will be set by TCM if RPM signal is below 470rpm for at least two seconds with vehicle speed greater than 25 mph. The PCM on the other hand is looking for the Crank signal for 1.4 seconds while cranking so maybe that is why the code was not also registered by the PCM. Did this warning light come on just after or before you began to experience this loss of power or ability to rev engine. Wonder if they are even related. Might be a good idea to recheck for any codes then clear them and see if anyone comes back. You also might try checking for correct signal voltage from the PCM to the TCM. First check by backprobing the PCM connector wire terminal 2O and then see if the same voltage is present at TCM terminal 1G or visa versa. Probably easier to get to the TCM anyway. The TCM is located to the left of the drivers footwell. Has two somewhat large connector to it with 12 wires in one and 15 in the other. The wire you are looking for is Green w/ Blue stripe and is in the smaller of the two connectors about in the middle. This wire should have approx 11 volts with key on and approx 5.5 volts at idle. That will tell us that if the TCM is indeed even getting an RPM signal.

[IMG]local://upfiles/1377/1525DB1054794797910B09824838167A.gif[/IMG]

[IMG]local://upfiles/1377/CD37BDD75C564497B24C4ED5C0AFE834.gif[/IMG]

 

I have erased the codes once before, and this is the second time I have pulled a p0725 without any other codes, but the first time I checked the Freeze data. I dont know what the PCM is or where it is located nor do I no where the #20 terminal is, and I did check the TCM , but there was no green wire with a blue stripe, so I checked the green wire with the black stripe in the middle of the small plug about the 4th terminal and had 11.7 volts with key on, and 6.10 volts for maybe 5 seconds with it running then it went to 13.74 volts and held steady. When the CEL came on this last time the car might have been rolling when it died and shut off. Could I have some kind of fuel problem or something else that might not even be related? I appreciate all your patience and help

 

doh, just dawned on me a bit ago about you saying the TCS light had been on. Is the ABS light also on? Seems odd that you do not have the HOLD light flashing or on and yet you have the transmission code P0725. If you have not yet cleared out all codes then lets take a look at ABS/TCS and see if RPM loss signal code is also being registered there. Easy to do and at least then we will know.
Need to locate the DIAGNOSIS connector under the hood. Should be gray box with that word imprinted on top in the right rear corner of the engine compartment. Open it up and ground the tbs terminal to battery negative. Check first diagram below. Now turn key to RUN position. ABS light should come on for 3 seconds, off for 2 seconds and then start flashing a code. Am looking to see if you have a code 17. That would be one long flash followed by 7 short, a pause, and then repeat the 17 again untill key turned off. See second diagram below for example of code 22. See if that code 17 'RPM circuit input failure' is stored by ABS system.

[IMG]local://upfiles/1377/194E9FA82F504A039BE4B8A299D65C21.gif[/IMG]

[IMG]local://upfiles/1377/5121965E9B0E4776955730A3FF268DF8.gif[/IMG]

 

Yes. I do have a code 17, and I think it is also putting out a code 50 which is from what it appears is 5 evenly spaced flashes that last about 1.5 to 2.0 seconds long then it goes back into a code 17. So now what can I do?

 

I figured out my ABS/TCM codes to be 17 engine speed (RPM) input signal circuit failure, 51 fail safe relay malfunction, and 82 torque reduction (request) signal circuit failure. It took me some time to figure out the difference in the values of the ones and tens place by the different timed blinks of the ABS light when I grounded the #13 pin in the ABS diagnostic box ( gray box left rear engine compartment. ) I still have to complete all the diagnostic aids ( tests ) according to my Mitchell repair cd.