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Severity: Moderate Code type: Manufacturer-specific (Chevrolet)

Chevrolet P1381 Code: Misfire Detected – No Communication With EBCM

A misfire was detected while the PCM had lost contact with the ABS module that supplies rough-road data.

Safety first · Consult a professional

  • Braking system affected: ABS may be disabled. Drive carefully and have it checked promptly.

At a glance

Severity: 3/5 – Moderate3/5

Severity: Moderate

Meaning
Misfire Detected – No Communication With EBCM
System
Ignition & Misfire · Powertrain
Safe to drive?
With caution
Typical repair cost
$10–$1,100
DIY difficulty
Moderate

On older Chevrolets the PCM and the ABS module (EBCM) share the GM Class 2 serial data line, and the EBCM uses it to send rough-road information that helps the PCM tell a genuine misfire from a jolt through the wheels. P1381 sets when a misfire code is ready to turn on the check engine light and, at that moment, the PCM hears nothing at all from the EBCM. Unlike P1380, where data arrives but is flagged invalid, this code is a communication failure. The EBCM may be unpowered, its connector may be corroded, the serial data wire may be broken, or the module itself may be dead. The misfire recorded alongside it still needs its own diagnosis.

Can I keep driving? Drive carefully and only as needed: with no communication, the ABS and traction control are usually offline, and there may be a real misfire. Stop driving if the check engine light flashes.

How to read P1381

How to read P1381P11233814
  1. P Powertrain
  2. 1 Manufacturer-specific
  3. 3 Ignition / misfire
  4. 81 Specific fault

Symptoms

  • Check engine light with a P030x misfire code
  • ABS and traction control lights on; ABS not working
  • Scan tool can't connect to the brake module ('no communication')
  • Other modules on the same data line may also be silent (gauges, radio or HVAC acting up)
  • Rough running if the misfire is genuine

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. EBCM without power or ground (blown ABS fuse, corroded ground, bad feed) 30%
  2. Corroded or water-logged EBCM connector (on trucks the module sits low on the frame near the brake modulator) 24%
  3. Open or shorted Class 2 serial data wire or splice between PCM and EBCM 18%
  4. Failed EBCM (internal electronics) 16%
  5. Genuine misfire combined with a temporary data-line dropout, e.g. low battery voltage 12%

Diagnosis step by step

Diagnostic flow: P13811Try to talk to the EBCM2Check ABS fuses and battery voltage3Inspect the EBCM connector4Test power, ground and serial dataat the module5Deal with the misfire

  1. Try to talk to the EBCM

    Use a scan tool that reaches the brake module. If the EBCM doesn't respond while other modules do, focus on the EBCM's power, ground and connector. If several modules are silent, the fault is on the shared data line or its splice.

    Tools: OBD-II scanner

  2. Check ABS fuses and battery voltage

    Check the ABS/EBCM fuses in the underhood box and confirm the battery rests at about 12.6 V and charges at 13.5–14.5 V running. Low system voltage can cause modules to drop off the network.

    Tools: Multimeter

  3. Inspect the EBCM connector

    Unplug the EBCM connector, look for green corrosion, water or pushed-back pins, and clean it with electrical contact cleaner. On frame-mounted units, road salt makes this a frequent culprit.

    Tools: Flashlight, Screwdriver

  4. Test power, ground and serial data at the module

    With the connector unplugged and key on, check the battery and ignition feeds and measure ground resistance (under about 5 Ω). The Class 2 serial data line should show a signal that varies around a few volts when the network is active; a steady 0 V or 12 V points to a short.

    Tools: Multimeter

  5. Deal with the misfire

    Once communication is restored, look at the misfire counters. Fix spark or fuel faults on any cylinder that shows real misfires, then clear all codes and road test.

    Tools: OBD-II scanner, Spark plug socket

Where the parts are

Charging system and control modules – P13811234567
Charging system and control modules
  1. 1Battery
  2. 2Alternator
  3. 3Engine computer (ECM)
  4. 4CAN bus
  5. 5Transmission
  6. 6Wheel speed sensor
  7. 7High-voltage battery

Repair options & costs

RepairDIY?Estimated cost
Replace ABS fuse / repair power feed Yes $10–$150
Clean or repair EBCM connector and ground Yes $60–$250
Repair Class 2 data wire or splice No $120–$400
Replace or rebuild EBCM (may need programming) No $350–$1,100
Ignition repair for the misfire Yes $100–$450

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Emissions / smog test impact

Will fail

Because a misfire code and P1381 keep the check engine light on, the vehicle fails US OBD emissions testing; many states also expect the ABS warning light to be off for a safety inspection.

Frequently asked questions

Why does P1381 mention the brake module?

The PCM needs the ABS module's rough-road data to confirm misfires. P1381 means the PCM couldn't communicate with that module when it detected a misfire.

Is it safe to drive without ABS?

The regular brakes still work, but wheels can lock up in hard stops on slippery roads. Drive more gently and allow extra stopping distance until the module is back online.

Does a rebuilt EBCM fix P1381?

Only if the module itself is dead. Check fuses, grounds and the connector first; many 'bad module' cases turn out to be corrosion or lost power.

Do I also have to fix the misfire?

Yes. P1381 is always stored with a misfire detection. Once communication is back, check the misfire counters and repair any cylinder that is actually misfiring.

Sources