This bulletin applies to 2009 Ram 2500/3500 trucks equipped with the Cummins 6.7L diesel engine built after March 4, 2009, programmed with bootloader software number 00 06 01 or later. An issue involving a no-crank, no-start and MIL on with DTC U1601 may be exhibited.
DTC U1601 involves ECU application software code 1 missing or corrupted.
If the ECM does not have a calibration installed, or has an unapproved calibration, then the ECM will be in a Read Only Memory (ROM) boot state. The ECM will have power but the lack of approved software will not allow the engine to be started and the vehicle driven. No further diagnostics of the ECM will be available at this time. This code will be cleared and the issue resolved when the ECM is updated with the correct approved calibration.
DTC U1601 code may also be set when a legitimate flash is interrupted for any reason.
Some customers may come in requesting a software update because the up-rate software does not recognize the secure bootloader software even though the controller may be up to date. This should serve as a warning that the customer is attempting to tamper with the calibration in the ECM. Up-rate kits are numerous and may include aftermarket software downloads.
Engines that have had tampering will generate excess soot and may damage the turbocharger, Diesel Particulate Filter and oxygen sensors and/or other emissions system(s), air handling or fuel control components.
Refer to the detailed service information available in DealerCONNECT>TechCONNECT under: Service Info>28 – DTC-Based Diagnostics>Module Engine Control (ECM), 6.7L>Diagnosis and Testing>U1601 – ECU Application Software Code 1 Missing or Corrupted.