P0A4B: Generator Position Sensor Circuit
What to do
If the engine will not start and this code is stored, the fault is in the hybrid system's ability to spin the engine, not in the engine itself — do not let the diagnosis wander into fuel pumps and crank sensors before this circuit is tested. Harness before resolver, as with the whole family.
What this code means
The generator's position sensor circuit has failed.
The resolver argument from P0A3F applies unchanged — but this machine's job list turns the consequence in a direction nobody expects: on most full hybrids the generator is also the engine's starter. It spins the engine up to firing speed through the transaxle, and it cannot be commutated without its rotor angle. So a generator resolver fault can present as an engine that will not start — cranking oddly or not at all — on a car whose engine, fuel system and twelve-volt battery are all perfect.
An engine no-start filed under hybrid position sensors is exactly the kind of cross-system misdirection that costs money: the corpus's own engine no-start pages (P0335 among them) all assume a conventional starter. On a full hybrid, this family belongs on that suspect list.
Likely causes
Start here
- Chafed harness between transaxle and inverter · moderate
- Corroded or loose connector · easy
- Open circuit in sensor wiring · moderate
Less common
- Faulty motor position sensor · specialist
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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