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changed transmission fluid, drove car, engine light came on and now in limp mode

30K views 85 replies 18 participants last post by  blue_devil 
#1 ·
I changed the transmission fluid and filter in my car. I followed the write-ups on this form but I used a dipstick that I got off Amazon that's supposed to be for these cars with the 6.1L. The tip was not user friendly. So when I put in the amount of fluid I thought was correct and went out to drive the car it initially shifted fine but seemed like it wouldn't go into overdrive. After I quickly realized that it wasn't shifting into the last gear I turned around to head back to the house. It was around this time the engine light or CEL came on and the car acted like I had put it in neutral until my speed got down to about 20 mph. Then it continued driving but no matter how far I depress the throttle it only goes about 20 mph. It reminds me of limp mode in my old 2000 323 BMW.

So I bought the Dorman dipstick everyone on this forum says to get and went back through my process. It looked like I was a little low on fluid but not by much. At temp the new dipstick showed about 60 mm. So I added fluid until I got to the proper level. But the CEL never went off and the limp mode or drivability issue did not change.

Any thoughts? I did the ignition key dance to see if any codes display but it did not show any. How can I clear the CEL without a scan tool?
 
#2 ·
Try disconnecting the battery for a bit and see if it resets?


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#3 ·
Did you observe transmission fluid temperature just prior to measuring fluid level? This is the only correct way to ensure proper fluid level.
 
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#4 ·
Thanks for the quick responses.

I have tried disconnecting the battery for several hours and then reconnecting. Did not change.

Unfortunately I do not have an accurate way to measure my transmission fluid temp such as indicated in the manual and numerous write-up. :sad: What I did that I'm sure is not extremely accurate is let the car idle for about 15 minutes, shifting between gears here an there. I then checked the temp with a temp gun pointed at the tranny pan. I also check the temp on the dipstick at that time. It was generally pretty close to each other. I used these measurements.

Also, I measured how much fluid I took out. Then put that much new fluid back in, plus about a half qt to account for residual fluid that I did not capture.

I bought a fluid transfer hand pump from the local auto parts store yesterday to suck out some fluid, to see if maybe that would help, as if I may have over filled it. This made no difference. The CEL is still on. I feel until it goes off I will see no change.
 
#5 · (Edited)
You really need to determine what Diagnostic Trouble Code(s) (DTC) have been set, otherwise you're blind.
 
#7 ·
I did just now go out and reconnect the battery after having both the positive and negative disconnected overnight. Cranked the car up, still have the engine light on. So then I did the deal where you pull out fuses 11, 14, & 16 and do a key on start on start thing from this thread, https://www.chargerforumz.com/threads/option-to-reset-your-adaptive-learning.82980/ , but still the same results. I'm heading now to the local auto parts store to see if I can get a scan tool to see what codes are present. I really hate to take it to a dealer. It almost seems as if it need the TCM or transmission adaptation procedure done but I've scoured the net and cannot find the direction on how to do this.
 
#9 ·
This is what Dealerships are for...

Note that garden variety OBDII codes readers will not display codes stored within the TCM. Generally, they will not clear on their own either...
 
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#11 ·
STEALERSHIPS. I'd rather not take it to a dealership. I've been working on my own cars for over 25 years. I've taken motors down to the block and rebuilt them. I've worked on electrical and mechanical issues. I'm a controls engineer by trade. So I figured something this simple should be no big deal. And it wasn't till now. Never seen a vehicle be such a big deal to check, change tranny fluid and filter.
 
#12 ·
I bought the fluid from a Dodge dealership. Mopar branded ATF+4. It's their stuff. I've read that incorrect fluid, or questionable quality fluid, or even just the least little bit of moisture in the fluid like 0.005% moisture can cause similar issues.

I've also read that codes in the TCM will not clear by disconnecting the battery or clearing with the generic code reader. I guess I'll have to buy a code reader that will check TCM codes or take it to a stealership. Which pains me to think about.

One of my friends came over yesterday with a generic code reader, couldn't read transmission codes. The CEL light was on due to a P0700 code - Malfunction in the transmission control system. That was the only code it showed. Reset that code. No change in drivability. After a few time the same code came back.

Likely due to stored TCM code. Anyone know of a code reader that will read Dodge TCM codes?
 
#13 ·
If you have an Android phone you can use a $10 bluetooth dongle (mini ELM 327) and a $5 app (Torque Pro) with a simple modification to the app to add a readout for the transmission temperature. Accurately reading that temperature is just as critical to getting the fluid level correct, as is the dipstick tool.

Details on adding the temperature readout to the Torque app are here -> [GUIDE] Displaying Transmission Temp NAG1 - Torque Pro (Android) - Chrysler 300C Forum: 300C & SRT8 Forums

You must follow the instructions regardless of the fact the name of the PID set you are adding seems incorrect. And, note that the reading must be taken with the transmission in gear. While in park, or neutral, it will show you the engine coolant temperature instead.

You can also clear your codes with Torque. It won't replace the full functionality of the scan tools that dealerships / pro shops use, those cost thousands, but Torque is a very handy tool for a tiny investment.

Richard
 
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#18 ·
If you have an Android phone you can use a $10 bluetooth dongle (mini ELM 327) and a $5 app (Torque Pro) with a simple modification to the app to add a readout for the transmission temperature. Accurately reading that temperature is just as critical to getting the fluid level correct, as is the dipstick tool.

Details on adding the temperature readout to the Torque app are here -> [GUIDE] Displaying Transmission Temp NAG1 - Torque Pro (Android) - Chrysler 300C Forum: 300C & SRT8 Forums

You must follow the instructions regardless of the fact the name of the PID set you are adding seems incorrect. And, note that the reading must be taken with the transmission in gear. While in park, or neutral, it will show you the engine coolant temperature instead.

You can also clear your codes with Torque. It won't replace the full functionality of the scan tools that dealerships / pro shops use, those cost thousands, but Torque is a very handy tool for a tiny investment.

Richard
There are so many bluetooth dongles out there, which one did you buy?
 
#15 ·
Thanks for the responses. I read them that day but just now getting around to responding. I've looked into BlueDriver. I think I'm going to order this today.

I have my car back on jackstands and ready to drop my fluid pan again. Using my fluid transfer hand pump yesterday I sucked back out from the dipstick tube all the fluid I could manage and fed it back into the 5 liter Mopar container it came from. It was just shy of filling back up to the level of which it was originally before using.

I'm going to drop the pan in just a few minutes to perform another visual check. I want to make sure the filter hasn't came out, and I want to check the pan and magnet again for anything suspicious. If the filter is still seated like it should be, I'm going to pull it out anyway, remove the metal casing, and check the filter for anything. Just to see. If all looks well I will put it all back together again with another new filter. I'm going to purchase more new fluid as well.

I'll report back here anything I find.
 
#19 ·
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#20 ·
The key thing with the ELM dongles is the Manufacturer / Vendor, in this case UniLink. The concern with the ELMxxx devices are knock-offs.

I know this one functions with iPhone / iPad:
https://www.amazon.ca/gp/product/B016C5722U/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

...and this for Android:
UniLink (TM) ELM327 WIFI Interface OBD2 OBD 2 WiFi Wireless Car Auto Diagnostic Scan Tool Code Reader for iPhone iPad iOS PC & Android Symbian WP system: Amazon.ca: Electronics
Thanks again for the quick response. It's appreciated.
 
#21 ·
Please let us know what root cause turns out to be. It benefits us all...
 
#23 ·
So I just finished dropping the fluid pan for the second time, just to run some checks.
What I did / verify:
  • Using a hand actuated fluid transfer pump I sucked out all of the fluid I could into measurable containers. One being the original 5 liter Mopar ATF+4 container. Then 2 other small containers that I'd cleaned, pre-measured level graduations and used.
  • 8.1 liters. Between what I removed using the pump and what I captured from the remaining fluid in the pan and the fluid that came out when I pulled the filter again.
  • Yes I did verify again what I extracted. I know, TOO MUCH fluid based on what I've found over 2 months or research, Dodge's TSB for an issue where they end up flushing the tranny 3 times, Dodge's official transmission section of their manual, and an AutoZone knowledgebase entry. Doing a tranny fluid and filter change I should have extracted somewhere around 4 to 5 liters. One of the very detailed write-ups I've found on this says after his detailed measurements he extracted just a hair over 4 liters. Dodge's manual says I should expect to add back about 5 liters.
  • I dropped the pan. Verified the gasket was on correctly, filter was still properly inserted and orientated. O-ring was still in place. Pan was clean. Valve body looked fine. Visual inspection showed nothing.
  • When I originally started this venture, I swapped out the multi-pin transmission connector. I wasn't having any issues, I just did it because I read so many people having issues with it. So I figured while I was at it, and it was cheap, I'd change it out. It was the original connector. I bought a Mopar replacement. Installed it. So during this time of rechecking I pulled it back out. Cleaned it up. Reinstalled it again.
  • I reinstalled the pan. Torqued to spec.

I also bought the Torque Pro $5 app from Google Play today, and I ordered from Amazon a bluetooth dongle for it. Hopefully the dongle will be here in a few days. Also, I am heading to the local Dodge dealership tomorrow to again purchase another gallon of ATF+4 so that when I put fluid back in, I will again be going in with new fluid.

After I get the dongle, install the new fluid, and make my checks I will report back here my findings and details.
 
#24 ·
I see you already ordered one; hopefully it works - in my somewhat limited experience, even the cheapies do. I have one that is a generic brand (transparent blue plastic and just says mini ELM 327 on the label), cost like $11, and works fine on my 300. Didn't work on my Chevy trucks so I spent about double that and got one from BAFX Products, one that is recommended by a number of people for GM applications. Of course it also works on my 300.

Richard
 
#25 ·
It's a weird market behind ELMxxx devices. The first two we ordered didn't work.
 
#28 ·
Too funny. The BAFX Products unit is actually the one I purchased. I went to their website to purchase and it linked me to their product on Amazon "Sold by: BAFX Products".

I'll report back here everything I come up with; good, bad, irrelevant.
 
#29 ·
Received the BAFX Products unit. I followed the link posted earlier in this thread by ' someotherguy ' and installed the transmission temperature custom OBD2 PID. The two components seem to work great. Thus far I have had no problems with them. On my 1st ever attempt to read fault codes it pulled the one I already knew I had, P0700. I used Torque Pro to clear it.

Using these components I was able to accurately fill my transmission to the proper level. I initially poured in 4.25L. Then began checking. Following the procedure from the Dodge manual I continued checking the fluid level and slowly adding in small amounts of fluid, a quarter of a quart at a time. All the while monitoring the tranny temp from my Torque Pro app, which you only get while in reverse or drive so I had my son helping me.

So ultimately when finished, at 168 deg F tranny temp I was clearly and consistantly getting 65mm fluid level on the Dorman dipstick. I ended up putting in 5.534 L / 5.85 qt of fluid.

***************************************
 
#30 ·
At this moment I have no leaks, no ECU codes, and it shifts into reverse and drive great. It takes off in drive great but still doesn't shift out of 2nd. You can feel the car sort of pull back when it's time to shift into 3rd, almost like it's trying to but it wont. According to the manual it still feels like it's in limp mode.

Also, according to the manual, it looks like if the TCM has a code in it, no matter if I fix whatever issue triggered it or not, it will never clear on its own nor go out of limp mode until you use a scan tool to clear the TCM codes. An like ' Hemissary ' said earlier an like I'd found out with investigation, the Torque Pro nor BlueDriver will do TCM codes. So now I'm trying to figure out my next step. The local O'reilly's Auto Parts says their code reader / scan tool will clear TCM codes but since it's 8 miles away an I can only drive 15 to 20 miles an hour I don't really want to drive down there if it will not clear TCM codes.

Any thoughts?
 
#31 ·
I'd be surprised if the O'Reilly unit will dig deep enough into the Seimens (Mercedes)-based TCM. As I understand it, TCM codes require a level of connection to apps that Chrysler licenses to for example StarSCAN / MOBILE back in the day and more recently WiTECH. Worth a try; I'd suggest first calling them and really getting them to convince you their unit (what is it btw) have indeed accessed and cleared level II DTCs.

The alternative is a 1hr charge at a Dealership to connect.
 
#32 ·
Only higher-end Snap-On and similar pro scanners will look into many ancillary systems like BCM and TCM. I might visit the local O-Reilly's and ask to see the scanner make & model, do a little homework on the mfrs site and see if it is likely to work. Absent that, I would recommend a slow drive to the dealer.
 
#34 ·
Eased down to O'reilly's. Their Bosh OBD1300 read and cleared TCM codes. Had a code of P0730 - Incorrect Gear Ratio. Cleared the code. Drove it down the street.

NOW it shifts fine from a stop all the way to 4th gear. It goes into 4th but after about 2 seconds the car feels as if someone pulled back on the car and is goes back to 3rd, engine light comes on, Torque Pro showes code. Went back to O'reilly's. Same code. Cleared it. Drove it again. Same thing. I went on and drove it home this time.

I can do the manual shift. I shifted from stop, in 1st, through to 3rd with no issues. I shift into 4th and again, after about 2 seconds or so it feels like a giant gently pulls the car back and it shifts back down to 3rd. I drove it have shifting manually from 1st to 3rd with no issues, up and down.

So now what?
 
#35 · (Edited)
The transmission is reverting to limp mode. You didn't by-chance install a differential with a different gear ratio (or grossly mismatched F / R tire sizes)?

You need to utilize the Factory Service Manuals we all have the luxury of downloading and follow the diagnostic process for that DTC.
 
#36 ·
The transmission is reverting to limp mode. You didn't by-chance install a differential with a different gear ratio?

You need to utilize the Factory Service Manuals we all have the luxury of downloading and follow the diagnostic process for that DTC.
No, didn't install a diff. While I had it in the air, I had new tires installed on my Viper replica 22's and I put those on during this process. So when I first ever took it off the jack stands and drove it after the fluid / filter change, I had those wheels on it. They do not have TPS in those wheels. So I don't know if that caused an issue. I have since taken those back off and reinstalled my factory SRT8 wheels that DO have the TPS in them to see if that would make a difference. No change.

Just to clarify though, I've had those Viper replica wheels on the car most of the time since 2010 and never had an issue other than with them on, my TPS dinging at me every now and then.

************

Where do I access the Factory Service Manual? I have searched for them several times over the last couple of months and have not found them. I've found a few threads that have a link to some sort of manual but it always take me to a FCA site that requires a user login and it appears to be a pay for service site.
 
#39 · (Edited)
K, that eliminates the obvious. Note the following is general (you need to drill down further). In the Service manual you will find under the section shown bellow associated DTCs (eg P0731 / 2 / 3 / 4 / 5).

P0730-INCORRECT GEAR RATIO

For a complete wiring diagram
Refer to Section 8W

Theory of Operation

The Transmission Control Module (TCM) constantly calculates the transmission ratio based on the input speed sensor

1 and 2 (N2-N3) signals and the calculated output shaft speed. The intent of this diagnostic is to detect if the

transmission is trying to mechanically shift into a lower gear then the TCM intends.

²
When Monitored:

Engine RPM greater than 450 RPM, output speed greater than 180 RPM, no N2 - N3 input speed sensor

errors present, no gear selector lever errors present, no ABS system errors, and all wheel speeds above 450

RPM.

²
Set Condition:

No shifting operation and detected gear is not the actual gear. No shifting operation - detected (calculated)

gear is less than actual (expected) gear, no plausible gear is calculated, actual turbine speed - calculated turbine

speed is greater than 300 RPM or calculated transmission ratio is above threshold. During an Upshift -

detected (calculated) gear is less than actual (expected) gear. During Downshift - detected (calculated) gear is

less than actual (expected) gear.

Possible Causes

INTERNAL TRANSMISSION PROBLEM

TRANSMISSION CONTROL MODULE

Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 -

TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)

Diagnostic Test

1.
CHECK FOR INTERNAL TRANSMISSION PROBLEM

Determine if there are any Transmission mechanical problems present.

Remove the Transmission Oil Pan and inspect for excessive debris or a plugged Transmission Oil Filter. (Refer to

21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1/FILTER - STANDARD PROCEDURE)

Is there any Transmission mechanical problems present?

Yes
>> Repair internal transmission as necessary per the Service Information. (Refer to 21 - TRANSMISSION/

TRANSAXLE/AUTOMATIC - NAG1 - REMOVAL)

Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/

TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)

No
>> Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion,

damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems

are found, replace the TCM per the Service Information. (Refer to 8 - ELECTRICAL/ELECTRONIC

CONTROL MODULES/TRANSMISSION CONTROL MODULE - DESCRIPTION)

Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/

TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)
 
#41 · (Edited)
So something I did at the same time I had the car up in the air while changing fluid/filter was I changed out my Crankshaft Position Sensor. I forgot about doing this but didn't think it would be an issue. I did this because for about the last 4 years the car periodically exhibits the symptoms of a bad crankshaft position sensor, and one time it triggered an engine light that when checked specified this sensor. It's never been a henderance and it would require pulling out the starter thus I put it off till now. So I'm not sure if this could have anything to do with the issue I'm having.

Went ahead and rechecked fluid at temp (detected with Torque Pro) again today. Spot on. Crazy how good it drives in reverse and manually shifting from 1 through 3rd. It goes into 4th smoothly and stays for 2 - 3 seconds and then drops back to 3rd and engine light comes on.

I've dropped the pan twice now and all looks good. So no to diagnostic check 1. The connections at the TCM connectors look good as well.

It worked great before the service so I don't understand why the TCM may be the issue, replacement. I thought about seeing of a shop would perform the TCM adaptation procedure. I called one of the local dealership service departments. The guy had no clue what I was talking about. Talked to the service manager. He had no clue either, but urged me to bring it in so they could go through it, troubleshoot it for me. I asked him if they'd ever had to work on or replace an LX body tranny, a NAG 1 tranny or a TCM and he said no. I said you've never had to do this and don't know what a TCM Adaptation Procedure is which is found in the Dodge service manual but you want me to bring my car to you to troubleshoot; no way bud.
 
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