Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pcm Code EO47, BCM-To-Pcm Data Problem: Action
PCM clears all BCM data from PCM memory, disables A/C clutch and turns on SERVICE ENGINE SOON light.
The PCM and BCM share information through the PCM-BCM data through the Universal Asynchronous Receiver Transmitter (UART). The BCM is in control of data link and data is only transmitted at the BCM's request. Data is sent in 8 character words at a rate of 8192 characters per second.
The data from the PCM to BCM contains engine operating information. The PCM-BCM data includes CTS, RPM and injector pulse width values so that the BCM can control cooling fans, display RPM and calculate MPG display at the CCDIC. The BCM sends the PCM air conditioning status to be used idle speed control and ambient temperature use in VCC application and release decisions.
Code EO47 is set in the PCM in event of a UART failure. If fault is a current failure, PCM will not be able to communicate with the BCM and Code B334 will be displayed as current. Code EO47 is current in the PCM but cannot be sent (displayed) to BCM because of UART fault. If the UART fault is corrected, both Code EO47 and B334 will be displayed as history codes.
Code EO47 can only be displayed as an intermittent. If fault is present, Code B334 will be current. Two failures can result in a Code EO47:
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.