P0726Engine Speed Input Circuit Range/Performance
- 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. P0726 means the engine speed value is present but implausible. The Allison 1000, which reads its own sensor, flags a jump of 600 rpm within 0.15 s or noise of ±650 rpm, with the engine above 600 rpm and a gear engaged, after two trips. Saab's 9-3 of 2000, which receives the value over the bus, flags more than 7200 rpm for at least 10 s. The converter clutch is then locked out and shifts may be harsh. No signal at all is P0727.
- 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 sensor at the transmission (Allison) dirty or faulty, loose contact
- PossibleInterference (shielding, ground)
- PossibleWrong bus value from the engine module (crankshaft sensor problem)
- RareTransmission module
- 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.