OBD-II Code

P1351

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$80–$480

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

Check engine light

Read the full diagnostic procedureP1351 is set when the PCM detects an unexpected high voltage on the ignition control (IC) circuit for one or more coils — typically the bypass or EST…+

P1351 is set when the PCM detects an unexpected high voltage on the ignition control (IC) circuit for one or more coils — typically the bypass or EST line on distributor-equipped GM engines, or the individual coil driver feedback line on coil-near-plug platforms. The PCM expects the IC line to be pulled low when it commands spark and to rise to system voltage during the off interval; a continuous high reading suggests an open driver, a shorted-high signal wire, or a coil module that isn't loading the line correctly.

Diagnose cheapest first

with key-on engine-off, backprobe the IC wire at the coil/ICM and verify it sits near 0V (the PCM holds the line low at rest on most platforms); if it reads battery voltage, disconnect the PCM connector and re-check — if it stays high, the wire is shorted to power; if it now reads zero, the PCM driver is suspect.
The expensive misdiagnosis: throwing a coil pack or ICM at the truck when the actual fault is a chafed IC wire arcing to a valve cover bolt under hard acceleration.

Vehicle-specific patterns1996-2005 S10/Blazer/Sonoma 4.3L Vortec sees P1351 from ICM (ignition control module) failure under the distributor cap — the module's heat-paste dri…+

1996-2005S10/Blazer/Sonoma 4.3L Vortec sees P1351 from ICM (ignition control module) failure under the distributor cap — the module's heat-paste dries and the driver fails high.
2000-2005Cavalier/Sunfire 2.2L Ecotec sets P1351 when the coil-on-plug harness chafes against the cam cover stud at cylinder #1.
1999-2007Silverado/Sierra 4.8L/5.3L/6.0L gets P1351 alongside multiple cylinder misfires when the underhood fuse block develops an internal solder crack on the ignition feed bus.
2004-2008Grand Prix 3.8L Series III throws P1351 from the ICM mounted on the rear coil pack overheating against the firewall.

Estimated repair$80 to $480.

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