P0355: Coil E open-load evidence needs the internal driver mapping

P0355 is the ignition coil E primary-control open-circuit entry. The cited GM row calls the coil “B”; the mapping between that internal label and generic E is not established without the installed calibration. The electrical monitoring principle can still be explained separately.

Feedback is assessed after ignition events

The controller watches for low voltage during the driver’s OFF state, interpreting it as open-load evidence. It requires ignition synchronization, engine speed above 1,400 rpm and a change of more than nine ignition-counter counts to establish that all cylinders have fired.

The documented detection interval is 0.4 second with two-trip reporting. This is not an instruction to compare every key-on coil terminal with a single voltage target; the command state and qualifying ignition history are part of the test.

Resolve the code-to-coil relationship first

Retain the actual manufacturer fault identifier and its driver context before selecting a coil location. Do not translate the generic E designation into the source’s B-labelled component or infer a cylinder number from either letter alone.

An unusually large upper supply boundary also appears in the row and is not used here as a practical service specification. Once the correct mapping is confirmed, the vehicle’s approved circuit procedure must localize the interruption. The monitor does not independently distinguish an open load from its harness or controller-side cause and does not establish a replacement verdict.

Source and applicability

This explanation covers the cited GM monitor, not every vehicle carrying this code. The application-matrix filename does not resolve cleanly to this file, so no model or engine fitment is assigned. GM diagnostic table, PDF page 701.