Help
I bought a 97 e420 with 132k on it.
very nice ride.
thought I got an excellent buy at 2500, but now not so sure.
Drove it a couple of weeks and was fine, until it suddenly felt like it was going into forward and reverse at the same time.
thankfully I was going slow.
pulled over and put into neutral, then it would coast, but when I tried drive it felt like forward and reverse togeather again.
turned engine off waited a bit then restarted and found I was in second gear only (limp mode).
took it to an indy to check it out (60.00) and they said it was probably the conductor board and wanted $1100.00 to replace it and couldn't guarantee that was all of the problem.
did some research and ended up getting a factory conductor board (new) and also the connector plug, gasket and filter, all for about 150.00 plus a case of shell 134 fluid for about 90.00 and did it in about 3 hours of my time.
went to a different indy to reset the codes and 60 bucks later found out that it did the same problem on the test drive after the reset.
started out fine then felt like it went into forward and reverse at the same time.
after a turn off and restart it was back in limp mode.
my money ran out till a couple of paydays go by so I could not pay for a couple of hours at 97.00 each at this point.

anyone have a thought.

again 132k on 722.6 trans fluid was clean, not burnt, no debris in pan.
thanks in advance.
Gemsbeme

Can you get indy 2 to read out your transmission fault codes?

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Prost!

Gemsbeme,

I hope you are planing on the car your self because it will be expensive to repair! Next I hope this is your second car!

The indie is charging you a fortune to fix the conductor plate fix. Out here they do it for about half the amount. Find another indie.

I think you need to run a ohm test on the two sensors, and the shift solenoids-See page14 in the part B PDF document.

You could have a stuck solenoid. A plugged screen filter for each solenoid, stuck valvebody piston, or broken spring-This is my guess.

Before doing anything. You fluid must be up to the level(buy 722.6 test dipstick-eBay or the dealer) I hope the fluid and filter are recent too. All guessing goes out the door if you find oil on the Electronic Transmission(ETC) Computer. Oil on the ETC will do all kind of weird things, but normally the car goes from working fine to limp mode, but really their is not symptom pattern. The ETC computer is in the engine bay(see page3 of part B).It is the black 1" thick module with two connectors. The module does not reference anything about it being the ETC, but you will recognize the connectors-Page 21 of partB.

If you find oil on the connector(you say oil???), oil wicks-up the control cable to the ETC. The ETC shorts out, but not damage it in most cases, but the Repair shops want to charge you for a new one, yet all you have to do is snap-open the ETC from the case, and clean it with Electronic Contact Cleaner(with no lubricant!!) Let it dry for about four hours, or overnight... Clean connector the connector too. The oil made it to the ETC from the connector on the outside of the transmission(the o-ring failed). Buy only dealer connector-no aftermarket, or used ones...

Hope this give you some guidance-This is what I would do..

Martin

Attached Files

Pages from 722_6_ETC_Error Code-PartA.pdf (706.0 KB, 811 views)

Part B

Attached Files

Pages from 722_6_ETC_Error Code-PartB.pdf (615.7 KB, 3199 views)

Conductor plate is about $200 and can be done DIY. Also change the shifter bushings as transmission will probably be getting sloppy by now.

__________________
With best regards

Al

Agreed, get the fault codes

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ok
I checked the TCM and found it was a replacement(ballpoint pen stating it was for a 97 e420).
had a very small trace of oil on the connectors, but the wires had been opened and are not in a sleve anymore, so the oil may have come up from the 13 pin connector on the tranny previously.
I took the sleve off of the TCM and the re was no oil present.however I noticed that someone had earlier pried the TCM open and had scraped a couple of traces enough to allow corrosion to build up between traces.
I felt that this could possibly be my problem so I cleaned the corrosion and made sure the traces were good and not shorted.
I then covered the exposed area with clear fingernail polish to prevent further corrosion.
with high hopes went back to indy 2, had the codes read and then cleared.
NO JOY!!
still same issues.
codes thrown are
po 730
055 selected gear not attained.
151 the gear comparison is sporadically negative or the target gear has sporadically not been achieved.
the fluid level was checked and correct at 80C.
the manual says to check harness, solenoid y3/6y2, and valves for full travel and ease of movement.
or possibly replace a valve spring if needed.

I think my next move is to remove the valve body and check the valve movement and check the resistance on all of the solenoids.
anyone have the specs for the resistance on the solenoids, and a source for replacement solenoid o rings?
any other suggestions will be greatly appreciated.
Gemsbeme

Gemsbeme,

You can test the solenoids from the harness connectors up from the ETC connectors, so you can qualify the harness integrity. I'd even fire each solenoid and measure the current draw to see if you have a shorted one.

If you get down to removing the valvebody, inspecting the solenoids. Take note of the metal etching on the case of the solenoid. it should say bosch as their are some Chinese one's out there, and may prematurely fail. The o-ring on the tip of the solenoind to valve body needs to fit tight and feel malleable-not hard or loose.

ETC is known to blow the one electrolytic capacitor(round looking part that looks like a can) inside. The part will swell. I'm not sure why it blows, but it may be because it comes in contact with oil. The capacitor MAY have the current dampening effect when the solenoids are fired(so the ETC does not go into limp mode). I will post picture later in the day of this capacitor.

Best of luck,

Martin

Here are the pictures:



The Case removed:

The capacitor on the upper left tilted to the right because it is ready to explode!



The capacitor is 100uF 35v 85 Degree C-Note the white stripe as it is the negative lead. The capacitor is a common size if the voltage is greater that is no problem. The capacitance of 100uf can be a little larger. The 85c is common but 105c would be great.



Inspect your module for the swollen capacitor. I'll have some more info for you later.

Martin

Here is the service manual:

Look at Page23

Mercedes-722-6

Best of luck,

Martin

please explain the method to test solenoids from the ETC connectors in order to verify that the solenoid and harness are good.
do you have a pin map and how much voltage and where to apply?
thanks to all of you for your help.
gemsbeme.

It is all in the part B document in post#4

Your legend for the W210 is on Page 20. Study the two attachments. The transmission oil thermistor(oil temperature) sensor has a legend in the service manual to show how much resistance per temperature. Use your dash temperature reading to give you an idea(on a cold engine)

Many voltmeters measure frequency-even the cheap ones. The modulating pressure solenoid oscillates between 1-2kilo-Hertz. This solenoid feeds oil to the valve body-This solenoid is very important it is working. In simple terms, it regulates oil!! Obviously the the speed sensors can be tested with a frequency monitor.

The solenoids are all 12v(11v-14v).

I know this frustrating, but this is day-in and day-out troubleshooting..

Best of luck,

Martin

One more thing, Like I said in post 3. A stuck valve or broken spring can do this too. I would take the valve body plates out, inspect the for broken springs, and stuck valves. Use the diagram below:

http://www.sonnax.com/downloads/valve-body-layouts/VBL-Mercedes-722-6.pdf

This is a no brainer to do, and worth the effort. I believe the valve body does not have to be removed to this.

Martin

First of all thanks to all who have put in their thoughts, it is much appreciated.
ok,
I have re removed the valve body and have started the physical inspection.
one thing I promptly found was the tcc/pwm solenoid was not actuating when voltage is applied.
all others were clicking solidly.
my question is can this part cause the error codes given?
055, 151, p0730.
the documentation I have points to y3/6y2 the shift pressure regulating solenoid.
the valve for y3/6y2 seems to be free and working properly.
I also tried to measure resistance on the solenoids with my digital multimeter and could not get any solid readings.
is the trans fluid on/in them interfering with this test?
should I clean them somehow?
if so what way is best?
any thoughts for all of this?

thanks.
gemsbeme

The easiest thing to do:

Use your multimeter DC current scale. I hope it has a DC current scale of 2Amps or more, but most meters will have a 10Amp Scale.

Put the meter in the 10amp scale. Place the meter in series with the solenoid. What i cannot tell you is the computer is switching the negative or the positive. The polarity of pin 6(on the conductor plate) will let you know. If pin6 has positive voltage the computer is switching the negative(meaning negative is pulsing the solenoids with a positive ground), so the following is a way to test each:

1) one meter lead to -12v.

2) other meter lead to non common lead of the solenoid(see schematic).

3) the other lead of the solenoid to +12v

The stuck solenoid(more than likely will draw more current-not always!).

See the following attachments in the next post.

Now, the Chrysler CrossFire has a 722.6 or NAG1(same thing). The service manual has an extensive troubleshooting section for the transmission in the transmission section. Check out the manual at:

722.6 transmission info - CrossfireForum.org

See post 3

Martin