P0726: Engine Speed Input Circuit Range/Performance
What to do
If you feel a shudder or the revs flare at a steady cruise, mention it — that changes this from a signal fault into an accurate report of converter slip, which is repaired quite differently.
What this code means
The engine speed value reaching the transmission module is present but does not agree with what the rest of the vehicle can see — most usefully, it does not reconcile with turbine speed and the gear believed to be engaged. A value that is merely noisy points at the signal path; one that is steady but wrong points at the source.
Worth knowing before chasing wiring: a genuinely slipping torque converter clutch produces engine speed that legitimately does not match turbine speed. The signal is accurate and the relationship it should satisfy has been broken by a mechanical problem elsewhere. Whether the vehicle shudders or flares at cruise separates the two cases.
Likely causes
Start here
- Faulty crankshaft position sensor · moderate
- Slipping torque converter clutch · specialist
Less common
- Loss of communication with the engine control module · specialist
- Damaged data bus wiring · specialist
- Low or degraded transmission fluid · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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