OBD-II Code

P1381

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)

$90–$850

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

P1381 is the sibling to P1380 — it sets when the PCM determines that the rough-road communication path is faulty (not just absent, but actively miscommunicating), typically because the message is arriving with a checksum error, a stale timestamp, or out-of-range values.

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 procedureP1381 is the sibling to P1380 — it sets when the PCM determines that the rough-road communication path is faulty (not just absent, but actively misco…+

Diagnose with a scan tool that can show bus traffic

monitor the EBCM's rough-road message at a 100 ms refresh rate while driving — the value should update smoothly and the message age should stay under 200 ms. If the message refresh is sporadic or the EBCM drops off the bus periodically, you have a bus-wiring issue or a failing EBCM. Check the GMLAN/Class 2 splice points (especially the body-side splice pack behind the IP on most GMT800/900 trucks) for green corrosion, and verify EBCM power and ground at the module connector with the engine running (battery voltage on the feed, less than 50 mV ground drop). The expensive misdiagnosis is replacing a PCM thinking it's a misfire-monitor calibration problem when the fault is a $0.50 splice clip that lost tension after 15 years.

Vehicle-specific patterns1999-2006 Silverado/Sierra 4.8L/5.3L/6.0L is the dominant P1381 platform — TSB 04-06-04-047 documents the EBCM-to-PCM rough-road suppression bug wher…+

1999-2006Silverado/Sierra 4.8L/5.3L/6.0L is the dominant P1381 platform — TSB 04-06-04-047 documents the EBCM-to-PCM rough-road suppression bug where the EBCM intermittently transmits a frozen Rough state, fooling the PCM and eventually setting P1381 as the freshness watchdog times out.
2002-2007Trailblazer/Envoy 4.2L I6 sees P1381 from the IP harness rubbing through at the steering column bracket.
2005-2010Cobalt 2.2L Ecotec throws P1381 when the BCM under the dash develops solder cracks at the Class 2 driver.
2007-2011Silverado 5.3L AFM with cylinder deactivation occasionally sets P1381 alongside legitimate AFM-induced rough running.

Estimated repair$90 to $850.

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