FLASHING "Trans Temp" and Tow Haul Indicators/Lights??

[CharlesHoward]

I don't recall ever seeing any tales about this particular issue since joining in 2007...

After getting my 2005 3500 Fuel Filter Housing replaced: On first short Drive home from the shop (167K Miles) on Friday Truck “beeped” a lot and TRANS TEMP and TOW HAUL lights flashed many times, NO Check Engine Light. I had NOT activated TOW HAUL. Ran Scan Tool and got PO643 Sensor Ref Voltage A Circuit High, and cleared Code. Took another drive on the HWY and these lights just flashed once. So probably good to go...?

Drove on Saturday to 14K lbs Fifth Wheel Trailer in RV Storage – NO problems. TOWING the trailer starting slowly okay, but on HWY got flashing TRANS TEMP and put in TOW HAUL mode – then both would flash. Got whooshing, wheezing, slipping sounds (Torque Converter?) accelerating on expressway. Got Trailer Home. Truck has PO868 Transmission Fluid Pressure Low, Cleared Code but now CHECK ENGINE light is on with NO code….Of course my Scan tool is inexpensive consumer grade...

Most recent Transmission Service was 8/19/2019 was while traveling with the Trailer: “Performed Diagnostics P 1753 – P1751. Replaced Governor Pressure Sensor and Solenoid. Serviced Transmission (New Filter and Fluid)". Towed Trailer successfully from Gadsden AL to home in Montgomery AL in July and to Tampa FL and back home in September 2019.

Were supposed to start our travel on Monday, but will take Ram to nearby well rated (online) Transmission Shop Ihave never been to a Transmission shop at home - only on the road !) but I wonder if its really the PCM (which was a very expensive replacement in 2014 (97 K miles)???

Thoughts or suggestions?

 

[p-Bar]

they can put a gauge on the trans and check pressure if within spec probably bad sensor

 

[CharlesHoward]

I hope it is just a bad sensor... I've had MANY Transmission Component Repairs/Replacements over the years (Performance and Check Engine Light were the indicators) but have never showed "Trans Temp" or illuminating the "Tow Haul" indicator when NOT in use...which makes me wonder if its an "electronic" failure...

 

[CharlesHoward]

I hope that's all it is! I wonder if the most recent service stirred things up...

 

[p-Bar]

There have been issues with cold solder joints on the 05 instrument panel. FYI

 

[CharlesHoward]

That could be, but more importantly the transmission shortly began to perform badly under stress and made a lot of noise.

 

[ChuckL]

had the same indications while travelling I-70 in mo.,,,, tbl was the temp sensor in the transmission, got a b.d. heavy duty unit good now

 

[AH64ID]

There have been issues with cold solder joints on the 05 instrument panel. FYI

I thought that was an 06 issue.

 

[p-Bar]

John now you have questioning myself .

 

[p-Bar]

Yes your right John more an 06 issue there were some 05's

 

[CharlesHoward]

Forgot to mention how the Lights were going off and lots of beeping parking (backing up) the trailer

 

[CharlesHoward]

Truck started - NO check engine light (or other lights)! I drove the Truck to the Transmission Shop via streets (2.5 miles) with only one hard acceleration and no problems.... Hope they can figure out why the Truck did not want to tow the trailer "comfortably"...

 

[CharlesHoward]

Transmission Shop says nothing wrong internally so they sent my truck next door to my regular shop for external electrical diagnosis...

 

[CharlesHoward]

Well today (Tuesday) the Shop sent my back to the Transmission Shop and the theory is the "pigtail" connection to the transmission is bad...

 

[cerberusiam]

Change the valve body harness in the trans, it is problematic. Have them check for pinched wires in the harness also, if care is not taken you could have have been compromised in a trans R&R or rubbed when the mounting broke.

 

[CharlesHoward]

The Transmission shop is still flummoxed! An electrical mystery...
They replaced the valve body harness and the external pigtail and the Governor Pressure Solenoid and Transducer. Cleaned several grounds.
They still get wildly fluctuating temp values (90 to over 200).
3 Days now in 2 Shops...

 

[CharlesHoward]

Shop took Test Drive and Truck is stuck in 3rd Gear and has put out various and many (?) trouble codes. Maybe its the ECM????

 

[CharlesHoward]

Shop gave up as they do not have a working "DRB III" analyzer (?) and is taking it the local Dodge Dealer on Monday so they can deal with my Truck as the Dealer still has a working DRB III. Guess we'll travel in our car versus towing our RV for the next few weeks....
Maybe I "broke" the ECM when I disconnected the batteries for a week...?
My personal thoughts were that's what was bad...

 

[sag2]

The P0643 is the Inlet air temp circuit. Try disconnecting the fan clutch harness and check it for corrosion. Possible bad fan clutch.
The governor pressure sensor could be a bad ground on the sensor circuit. If the voltage is close to 5v the ground is open. There are 4 inline connectors on the K900 sensor ground between the ECM and transmission solenoid.

 

[CharlesHoward]

On Thursday the Shop couldn't get the Truck out of 3rd Gear. Today they drove it to the Dodge Dealer and no problems/no check engine light. Dodge Dealer has the DRB III and may get to it tomorrow or Wednesday. I asked that if a new ECM is needed what would that entail, they said at least a week (Xmas is next week of course...) or maybe a month or more. I was shocked by that response as I assumed Chrysler would have a "network/dealer" ready solution as obviously the ECMs have a notable failure rate (this could be my SECOND one!) If it comes to that maybe I can persuade them to get it repaired or replaced from someone online like SIA or autocomputerspecialist.com.
Hopefully its just some other Electrical (well hidden?) or the ECM can be reflashed (?) and that's it...