Pulled into the garage tonight and saw the CEL. Scanned and got P1755. It WON'T go away. Truck will barely shift out of first gear. I can find VERY little on this code. Seems powertrain related for certain.

Truck will barely shift out of first gear~2500 rpm at very light throttle. Thereafter everything seems normal.

Any ideas???

Thanks!!

 

P1755 is the error code for failure of the Intermediate Speed Sensor (ISS) malfunction.

 

Thank you sir. That was at the top of my list. Now, where is this thing and how is it changed???? I tried removing a sensor basically under the drivers side seat that had two contacts. I believe about a 1" socket. Trans fluid poured out ALL over the place.

 

Well........... replaced speed sensor as well as AB Actuator- throttle valve actuator, which is what the code really points to, and same problem. Checked all harnesses, etc.

any more ideas???

Thanks

 

Theory of Operation
The transmission throttle valve cable has been replaced by the transmission throttle valve actuator (TTVA) . The TTVA consists of an electric DC motor, two potentiometers, and a gear drive system. The TTVA is mechanically connected to the transmission throttle valve in the valve body by the "D" shaped opening in the bottom of the TTVA shaft.
The Transmission Throttle Valve Actuator (TTVA) does not require any mechanical adjustments. All changes in throttle valve position are controlled by the Engine Control Module (ECM) .
The TTVA does require an initialization period after the actuator has been removed or replaced. After the actuator has been removed or replaced, move the ignition to the ON position for thirty (30) seconds. This will allow the ECM sufficient time to perform the internal calibration procedures to learn the TTVA's current "zero" position.


When Monitored: Continuously with the ignition on.
Set Condition: The current detected on the TTVA circuit is greater than a threshold for a calibrated amount of time or the feedback to the controller does not match the intended state.


Possible Causes



(F856) 5 VOLT SUPPLY CIRCUIT OPEN
(K314) TTVA MOTOR (+) CIRCUIT OPEN
(K315) TTVA MOTOR (-) CIRCUIT OPEN
(K314) TTVA MOTOR (+) CIRCUIT SHORT TO GROUND
(K315) TTVA MOTOR (-) CIRCUIT SHORT TO GROUND
(K314) TTVA MOTOR (+) CIRCUIT SHORT TO VOLTAGE
(K315) TTVA MOTOR (-) CIRCUIT SHORT TO VOLTAGE
(K314) TTVA MOTOR (+) CIRCUIT SHORT TO ANOTHER CIRCUIT
(K315) TTVA MOTOR (-) CIRCUIT SHORT TO ANOTHER CIRCUIT
INTERNAL TRANSMISSION
TRANSMISSION THROTTLE VALVE ACTUATOR
ENGINE CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


CHECK IF THE DTC IS CURRENT Ignition on, engine not running. With the scan tool, read Engine DTCs. Record the Freeze Frame data for the reported DTC. With the scan tool, erase DTCs. Turn the ignition off to the lock position. Using the Freeze Frame data recorded earlier, try to duplicate the conditions in which the DTC originally set. NOTE: It may be necessary to road test the vehicle to duplicate the original set conditions. With the scan tool, read Engine DTCs. Did the DTC reset? Yes >> Go To 2 No >> Go To 12
CHECK THE TTVA






Turn the ignition off to the lock position.
Disconnect the TTVA harness connector
Connect a 12-volt test light between the (K314) TTVA Motor (+) circuit and the (K315) TTVA Motor (-) circuit in the TTVA harness connector. Monitor the test light in the following step.

NOTE: The test light should momentarily flash brightly, one time, immediately after the ignition is turned to the on position. Ignition on, engine not running.

Did the test light illuminate brightly one time after turning the ignition to the on position?
Yes >> Go To 3
No >> Go To 4



CHECK THE (K315) TTVA MOTOR (-) CIRCUIT FOR A SHORT TO GROUND






Turn the ignition off to the lock position.
Disconnect the ECM C1 harness connector.
Measure the resistance between ground and the (K315) TTVA Motor (-) circuit.

Is the resistance below 5.0 ohms?
Yes >> Repair the (K315) TTVA Motor (-) circuit for a short to ground.


Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests No >> Check the Transmission Throttle Valve components for proper movement or sticking. If no problems are found replace the TTVA per the Service Information

CHECK THE (K314) TTVA MOTOR (+) CIRCUIT FOR AN OPEN








Turn the ignition off to the lock position.
Disconnect the ECM C1 and C2 harness connectors.
Measure the resistance of the (K314) TTVA Motor (+) circuit between the ECM C1 harness connector and the TTVA harness connector.

Is the resistance below 5.0 ohms?
Yes >> Go To 5
No >> Repair the (K314) TTVA Motor (+) circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER -1 (DIESEL). See: Verification Tests



CHECK THE (K315) TTVA MOTOR (-) CIRCUIT FOR AN OPEN




Measure the resistance of the (K315) TTVA Motor (-) circuit between the ECM C1 harness connector and the TTVA harness connector.

Is the resistance below 5.0 ohms?
Yes >> Go To 6
No >> Repair the (K315) TTVA Motor (-) circuit for an open.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests


CHECK THE (K314) TTVA MOTOR (+) CIRCUIT FOR A SHORT TO GROUND








Measure the resistance between ground and the (K314) TTVA Motor (+) circuit.

Is the resistance below 5.0 ohms?
Yes >> Repair the (K314) TTVA Motor (+) circuit for a short to ground.


Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests No >> Go To 7

CHECK THE (K314) TTVA MOTOR (+) CIRCUIT FOR A SHORT TO VOLTAGE




Ignition on, engine not running.
Measure the voltage of the (K314) TTVA Motor (+) circuit.

Is the voltage above 0.5 volts?
Yes >> Repair the (K314) TTVA Motor (+) circuit for a short to voltage.


Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests No >> Go To 8

CHECK THE (K315) TTVA MOTOR (-) CIRCUIT FOR A SHORT TO VOLTAGE






Measure the voltage of the (K315) TTVA Motor (-) circuit.

Is the voltage above 0.5 volts?
Yes >> Repair the (K315) TTVA Motor (-) circuit for a short to voltage.


Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests No >> Go To 9

CHECK THE (K314) TTVA MOTOR (+) CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT








Turn the ignition off to the lock Position.
Measure the resistance between the (K314) TTVA Motor (+) circuit and every other circuit in the ECM C1 and C2 harness connectors.

Is the resistance below 5.0 ohms between the (K314) TTVA Motor (+) circuit and any other circuit in the ECM C1 and C2 harness connectors?
Yes >> Repair the (K314) TTVA Motor (+) for a short to another circuit(s).


Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests No >> Go To 10

CHECK THE (K315) TTVA MOTOR (-) CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT





Measure the resistance between the (K315) TTVA Motor (-) circuit and every other circuit in the ECM C1 and C2 harness connectors.

Is the resistance below 5.0 ohms between the (K315) TTVA Motor (-) circuit and any other circuit in the ECM C1 and C2 harness connectors?
Yes >> Repair the (K315) TTVA Motor (-) for a short to another circuit(s).
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests
No >> Go To 11


CHECK THE ECM OPERATION







Turn the ignition off to the lock position.
Reconnect all previously disconnected connectors.
Turn the ignition on for the period of 30 seconds to allow the ECM to reset.
Turn the ignition off to the lock position.
Disconnect the TTVA harness connector.
Connect a 12-volt test light between the (K314) TTVA Motor (+) circuit and the (K315) TTVA Motor (-) circuit in the TTVA harness connector.
Monitor the test light in the following step.

NOTE: The test light should momentarily flash brightly, one time, immediately after the ignition is turned to the on position. Ignition on, engine not running.

Did the test light illuminate brightly one time after turning the ignition to the on position?
Yes >> Go TO 12
No >> Using the schematics as a guide, check the Engine Control Module (ECM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the ECM per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests



INTERMITTENT WIRING AND CONNECTORS The conditions necessary to set this DTC are not present at this time. Use the Freeze Frame Data to help duplicate the conditions in which the DTC originally set. Pay particular attention to the DTC set conditions, such as, VSS, MAP, ECT, and Load Using the schematics as a guide, visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals. Wiggle the wiring and connectors while checking for any possible open or shorted circuits. Check for any Service Information Tune-ups or Technical Service Bulletins that may apply. Were there any problems found? Yes >> Repair as necessary. Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). See: Verification Tests No >> Test Complete.



Clear as mud?

 

Isn't the speed sensor on one of the rear wheels or in the trans?

 

That's the vehicle speed sensor. This is an internal (trans.) speed sensor. This has been replaced. I am contemplating dropping the pan, although, my gut still says electrical. I have wiggled all harnesses, etc. The code simply threw pulling into garage Monday. I have not gone near the ECM yet or its connectors.

Also, we did verify movement of the transmission throttle valve manually.

Unless I am missing something, I don't see how it is possible to remove ECM harness C1 or C2. Just won't happen.

 

53 ****** - you should get a prize for the longest post ever!


Great tech info, though...

 

Thanks, I know that's some serious diagnosis.

 

No doubt!

If it was a simple fix, you could just turn the radio up...

 

I am getting this same code, as well as the ABS and Brake lights. Where is the TTVA located on the trans and which connector is it? The pictures are missing from the above post so I don't know where to start

 

What is your truck?

 

06 4x4 quad cab. Used to be a 6 speed and now has a 48re

 

I experienced this code today as well. I had a very strange shift issue on the way to work around the 2-3 shift I believe. Trans just quit pulling and after some pedal input finaly "found a gear" and started pulling again normal.

I will add that my dual optima red tops are getting weak. Lately in the morning I have to jump start the truck but the rest of the day the batteries start the truck just fine. Could this be related? Low voltage causing the ECU to lose the TTVA settings?

 

Got a P1755 error code in my 2006 Dodge cummins ... it never shifted funny .... So first step I replaced both batteries they were bad ... cleared the code and it has not reappeared could it have been just bad battery's? Going out and pull a load this morning ...