Engine Speed Input Circuit
What it means
P0725 means the transmission control module isn't getting a reliable engine-speed (RPM) signal on its input circuit. The transmission uses engine speed to time shifts and torque-converter lockup, so a missing or erratic signal typically causes harsh or wrong-timed shifting or limp mode — not a no-start, since this is an input to the transmission rather than something the engine needs to run. It usually traces to the crankshaft/engine-speed sensor, its wiring, or the data link.
Can I keep driving? Usually drivable — the engine still starts and runs, but the transmission may shift harshly, at the wrong points, or drop into limp mode without a reliable RPM signal.
Common symptoms
What you'll notice
- Check-engine light on
- Harsh, erratic, or wrong-timed shifting
- Transmission slipping into limp/failsafe mode
- Shift points that don't match engine speed
Common causes
Most likely first
- Faulty engine-speed (crankshaft position) sensor feeding the signalLikely
- Wiring or connector fault in the engine-speed input circuitCommon
- Loss of the engine RPM signal shared over the data busCommon
- Faulty transmission control module (less common)Less often
How to diagnose & fix
Work through it in order
- Scan and compare the engine RPM the transmission module sees with the actual tachometer reading.
- Inspect the engine-speed sensor and its wiring and connector.
- Check the data-bus communication carrying RPM between modules for faults.
- Replace the sensor if it tests bad; suspect the control module only after wiring and bus are verified. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0725?+
Can I just clear P0725?+
Related codes
Often seen with P0725
Read & clear P0725 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.