There was an ECM upgrade(replacement) did you have that done yet? Also this:
TECHNICAL SERVICE BULLETIN
Reference Number(s): KT2009083101, Date of Issue: June 01, 2009
Related Ref Number(s): KT2009083101
Upon encountering powertrain DTC's, check that the powertrain main ground is good before
attempting any repairs.
When diagnosing any "P" or "C" Diagnostic Trouble Code (DTC) in which normal diagnostic steps
do not quickly reveal the problem, check that the powertrain assembly is properly grounded to the
Powertrain assemblies all have at least one ground to body/chassis/battery and in some cases more. A
poorly grounded powertrain assembly does not necessarily produce a "string" of DTC's; check the
connections even if you only retrieve one or two DTC's. Not identifying the poor ground can (and
does!) Lead to many hours being spent and parts being replaced unnecessarily.
Be aware that a quick voltage drop check between the powertrain and body/chassis/battery while at
engine idle or in the shop under low load conditions may not reveal this concern. Powertrain ground
requirements increase linearly (and substantially) with higher RPM/load conditions. It may be
necessary to drive the vehicle under similar RPM/load conditions as when the code set while taking
voltage drop recordings with a "min/max" capable digital volt meter.
Any indications of a poorly grounded powertrain assembly should be investigated and corrected prior
to performing any further in-depth repairs.
Saturday, April 7th, 2012 AT 12:56 PM