What it means
The transmission control module monitors the park position sensor or switch A signal for stable operation. It sets this code when the signal fluctuates, drops out, or changes erratically instead of tracking park position consistently.
At a glance
- Usually lights the check-engine light
How it works
Park position sensor or switch A reports its state to the transmission control module through circuit A. P07B7 sets when that signal fluctuates, drops out, or changes erratically instead of remaining stable as park position is monitored.
Common causes
Most likely first.
- Switch contact bounce
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
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
- Review freeze-frame data and monitor sensor A's live signal while changing positions to see whether it drops out or jumps unexpectedly.
- Inspect sensor A's connector for loose fit, corrosion, or terminals that may lose contact with vibration.
- Follow circuit A along its route and look for chafing or contact with a vibrating component that could intermittently disturb the signal.
- With the vehicle secured, gently move the accessible harness while watching live data to check for a repeatable signal interruption.
- If the fault persists with sound wiring and connections, test sensor or switch A and the module input according to the manufacturer's procedure.
Common fixes
- Secure the circuit A harness away from vibration or rubbing points.
- Clean, tighten, or repair an intermittent sensor A connector contact.
- Repair damaged wiring that causes the signal to drop out when moved.
- Replace sensor or switch A if its contacts produce an erratic signal during testing.
Can I keep driving?
Use the parking brake whenever parked and pay attention to any changing gear indication or shift behavior. If the signal fault is accompanied by unpredictable shifting or limp mode, avoid driving until the transmission can be checked.
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.