P0727Engine Speed Input Circuit No Signal
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- The transmission module needs engine speed for converter slip, shift quality and to check the turbine speed. Today it almost always arrives over CAN from the engine module with a validity flag; only GM's 2007 Allison 1000 tables show a separate engine speed sensor read by the transmission module. P0727 means the engine speed signal is missing although the transmission is turning. The Allison 1000 flags under 61 rpm for 4 s with turbine speed of 400 rpm or more, after two trips; Saab's 9-3 of 2000 input speed above 2000 rpm for more than 5 s without engine speed; a 2006 GM table the CAN engine speed failing to answer. The module then works without converter slip information, usually locks out the converter clutch and may enter limp mode.
- What you may notice
- Transmission warning lamp, possibly check engine light
- Torque converter clutch locked out
- Harsh shifts or limp mode
- Often an engine code (crankshaft sensor) as well
- Likely causes
- LikelyEngine speed wire or connector open, or own sensor (Allison) faulty
- PossibleCAN communication between engine and transmission module disturbed
- PossibleCrankshaft sensor fault in the engine module
- RareTransmission module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.