ECM Code EO47: BCM-To-ECM Data Problem: Action:
ECM clears all BCM data from ECM memory, disables A/C clutch and turns on SERVICE ENGINE SOON light.
The ECM and BCM share information through the ECM-BCM data link. 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 ECM to the BCM contains engine operating information. The BCM sends the ECM air conditioning status to be used for idle speed control and ambient temperature for use in VCC application and release.
Code EO47 is set in the ECM in the event of a data link failure. If it's a hard failure, the ECM will not be able to communicate with the BCM and Code B334 will be current. Code EO47 is current in the ECM but cannot be sent (displayed) to BCM because of data link fault. If data link fault is corrected, both Code E047 and B334 will be displayed as history codes.
Code E047 can only be displayed as an intermittent. If fault is present, Code B334 will be current. Two failures can result in a Code E047:
- Open in circuits No. 800E and 800F. The symptoms will be: A - SYSTEM FAULT message on CCDIC panel. B - SERVICE ENGINE SOON and CHECK INFO CENTER lights on. C - Diagnostics entered and NO ECM DATA is displayed on CCDIC panel. D - When repaired, diagnostics will show Code EO47 as history and Code B334 as current codes until key is cycled to off.
- Grounded circuit No. 800 at any point. Symptoms will be: A - SYSTEM FAULT message on CCDIC panel. B - SERVICE ENGINE SOON light on. C - Instrument panel gauges will flash. D - Climate control panel goes blank. E - Engine cooling fans go high. F - Diagnostics disabled, SYSTEM FAULT message stays on CCDIC panel. G - When repaired, diagnostics will show Codes E047, B334, B335, B336 and B337 as history codes.