What it means
The transmission range control module communication circuit signal is below the expected level. The exact cause depends on the vehicle's communication circuit.
At a glance
- Usually lights the check-engine light
How it works
The transmission range control module uses a communication circuit to exchange information with other vehicle modules. P07F3 sets when the circuit's signal is below the expected level; a bus short to ground or a network routing fault can cause this, depending on the vehicle's design.
Common causes
Most likely first.
- Bus shorted to ground
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Record freeze-frame data and scan all modules for network codes to see which devices report a low communication signal or loss of messages.
- Check whether the range control module responds consistently to the scan tool and note any modules that disappear at the same time.
- Inspect accessible network wiring and connectors for chafing, corrosion, loose pins, or contact with ground.
- Check the range control module's power and ground circuits to rule out a supply problem affecting communication.
- Test the communication bus for a short to ground and inspect network termination only as directed by the vehicle's diagnostic procedure.
- If wiring and termination check out, investigate gateway routing and the range control module using the manufacturer's diagnostic steps.
Common fixes
- Repair a communication wire shorted to ground.
- Clean or repair corroded or loose network connector terminals.
- Repair a damaged harness or restore correct routing away from ground contact points.
- Correct a confirmed gateway routing fault or network termination fault.
- Replace the range control module only after verifying the bus, power, and ground.
Can I keep driving?
If shifting is abnormal or the transmission enters limp mode, avoid unnecessary driving until the low communication signal is diagnosed. An unreliable network connection can interrupt range information and transmission control.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.