PIT-4865

GMC/CHEVROLET: THE SPEEDOMETER BEING INOPERATIVE AND/OR THE SES MIL ON. WHEN CHECKING FOR DTCS THE ECM WILL HAVE A P0502 OR P0500 SET. THIS ISSUE MAY BE INTERMITTENT AND FOLLOWING NORMAL DIAGNOSITC IN SI2000 MAY NOT LEAD TO A CORRECTION. THIS CONCERN COULD BE CAUSED BY THE TCCM (TRANSFER CASE CONTROL MODULE) NOT COMMUNICATING ON THE CLASS 2 BUSS. THE 4WD SYSTEM MAY WORK NORMAL, BUT WHEN USING THE TECH 2 TO COMMUNICATE WITH THE TCCM IT WILL NOT COMMUNICATE. C4500-C5500 SERIES. *PE