What it means
The transmission control module monitors the transmission mode switch C circuit voltage. It sets this code when the signal falls below the expected range, indicating an electrical low condition in that circuit.
At a glance
- Usually lights the check-engine light
How it works
Transmission mode switch C provides the transmission control module with one of the inputs used to identify the selected driving mode or selector state. P07CC sets when the voltage on switch C's circuit falls below the expected range, such as from a grounded wire or poor terminal contact.
Common causes
Most likely first.
- Switch wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 check scan-tool data for transmission mode switch C while selecting the available modes to see whether its state changes as expected.
- Inspect the switch C connector and harness for corrosion, moisture, pushed-back pins, or insulation rubbed through against ground.
- With live data displayed, gently move the switch C harness and connector to check for an intermittent loss of signal.
- Use the wiring diagram to check switch C's signal circuit for a short to ground and inspect terminal contact and continuity.
- If the wiring is intact, test the mode switch C and the transmission control module input circuit against the manufacturer's specification.
Common fixes
- Clean and secure corroded or loose mode switch C connector terminals.
- Repair chafed wiring or a switch C signal wire shorted to ground.
- Repair a damaged connector pin or loose connection at the switch or module.
- Replace the mode switch or selector assembly if its switch C output fails testing.
Can I keep driving?
If the selected mode is recognized and shifting feels normal, drive cautiously to a repair location. Avoid relying on an unconfirmed mode selection; stop if the transmission engages unexpectedly, shifts harshly, or enters limp mode.
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.