Two transmission codes on the same scan. Neither one is a good sign, but neither one automatically means you need a new gearbox either. P0713 and P0753 show up together often enough that it's worth understanding what each one actually means before you start throwing parts at the problem.
What Is P0713?
P0713 is "Transmission Fluid Temperature Sensor Circuit High Input." The transmission fluid temperature sensor (TFT sensor) monitors how hot the fluid is inside the gearbox. The transmission control unit (TCU) uses this reading to adjust shift timing, torque converter lockup behaviour, and line pressure.
"Circuit high" means the sensor is sending an abnormally high voltage or resistance signal back to the TCU. The computer reads this as an impossible temperature reading, so it puts the transmission into a protective mode. You might see delayed shifts, harsh shifts, or the gearbox holding a single gear.
Common causes of P0713:
- A failed TFT sensor (most common fix)
- Corroded or damaged connector at the sensor
- Damaged wiring between the sensor and TCU
- In rare cases, a failed TCU
The TFT sensor lives inside the transmission pan on most applications, attached to the valve body or internal wiring harness. The part itself is $30-80 USD ($45-120 AUD). Getting to it requires dropping the pan, which is also a good time to replace the fluid and filter.
What Is P0753?
P0753 is "1-2 Shift Solenoid A Circuit Electrical." The key word is electrical. This code does not mean the solenoid is mechanically seized or blocked.Shift solenoids are small electro-hydraulic valves inside the valve body. They open and close to direct fluid pressure, which is what physically moves the gearbox between gears. The 1-2 shift solenoid controls the transition between first and second gear specifically.
When P0753 sets, the TCU either can't send the correct signal to the solenoid, or it's not getting the expected response back. The transmission might get stuck in a single gear, refuse to shift into second properly, or drop into limp mode.
Common causes of P0753:
- Failed shift solenoid
- Wiring damage or chafing between the TCU and solenoid
- Contaminated fluid blocking solenoid operation
- A failed TCU (less common, but it happens)
Why Do They Show Up Together?
On Jeep, Dodge, and Chrysler vehicles, the transmission's internal wiring harness is a known weak point. The connectors corrode, especially on trucks that see winter road salt, muddy tracks, or river crossings. One damaged connector can throw multiple codes at once.
The 2000-2006 Dodge Ram 1500 is a classic example. The 45RFE and 42RLE automatics in these trucks are mechanically solid, but the internal harness deteriorates. You'll often see P0713, P0753, and other transmission codes appear together when the harness starts failing, because multiple circuits share the same connector or run through the same section of harness.
On newer platforms like the Jeep Renegade with the 9-speed 948TE automatic, the picture is different. The 948TE has well-documented shift quality issues. Solenoid durability is a genuine concern on these, and the codes are more likely pointing at actual component failure rather than wiring.
Where to Start Diagnosing
Before buying anything, check the fluid. Burnt, dark, or low fluid causes both electrical and mechanical transmission faults. Heat degrades sensors, solenoids, and clutch packs. Pull the dipstick (if your vehicle has one), check the colour and smell. Dark brown or black fluid with a burnt smell needs to be changed before anything else.
If the fluid looks reasonable, the next step is the wiring. Drop the pan and inspect the internal harness. Look for chafed insulation, green corrosion on connector pins, or wiring that's rubbing against a sharp edge. This is where a lot of these faults actually live, and it's a much cheaper fix than replacing solenoids.
From there, test the TFT sensor with a multimeter. Compare the resistance reading to the spec in your service manual. Outside spec, replace it.
Test the shift solenoid the same way. Most shift solenoids read 10-15 ohms when healthy. If yours is open circuit or far outside that range, replace it.
If both tests pass, you're looking at wiring between the harness and the TCU, or a TCU fault.
What Does the Repair Actually Cost?
Fluid and filter service: $150-250 USD ($220-370 AUD).
TFT sensor replacement including labour: $200-350 USD ($300-520 AUD).
Shift solenoid: The part runs $50-150 USD ($75-220 AUD) depending on the application. Labour to drop the pan, swap the solenoid, and refill is another $150-350 USD ($220-520 AUD). All up, expect $250-500 USD ($370-740 AUD).
Internal wiring harness: $200-600 USD ($300-900 AUD) for the part, with significant labour on top if it's running through the transmission case.
Valve body replacement: If multiple solenoids have failed or the valve body bores are worn, a remanufactured valve body runs $300-800 USD ($450-1,200 AUD) plus labour. On a Dodge Ram or similar truck, the whole job might run $700-1,200 USD ($1,050-1,800 AUD) at a transmission shop.
TCU replacement and reprogramming: $300-900 USD ($450-1,350 AUD) for the unit, plus labour and dealer programming. This is always a last resort, not a starting point.
Can You Keep Driving?
Short answer: not for long.
P0713 puts the transmission in a protective mode that restricts normal operation. P0753 means the gearbox can't shift between first and second properly. Driving in this state increases heat and wear on everything inside the transmission.
Get the fluid checked today. Get it to a shop within a week or two. This is not a "see how it goes for another month" situation. Try TorqueBot Free | Download on iOS | Get it on Android