EA4-x NTC 0x0AF LoaIvtrIdptSigNrFlt

Nexteer Confidential

LOA Inverter Independent Signals Number Fault Overview
NTC 0x0AF.0

FDD: SF049A

Description:

SF049A Loss of Assist Manager(LoaMgr) tries to avoid system shutdown when safe sensor redundancy is still in tact.  However, customers want to prevent EPS from operating when issues occur repeatedly across ignition cycles.  Nexteer’s strategy is to provide NTCs for each issue to be tracked.

Diagnostic Overview:

Input signal Inverter Independent Signals represents the currently active number of Inverters.  When the number of independent signals is equal to or less than a calibration in LoaMgr, the fault status is set instantly to Failed.  LoaMgr can react instantly because the function providing the input signal is expected to debounce before dropping to a lower value.

Typical Fault Response:  

1. • –LOA Based Systems 

1. • • •Response of the diagnostic is F3.
        

Probable Sources (Most to Least Probable):

1. • –This fault should never get used in single-inverter EA3 programs because the IvtrIdptSig_Cnt_u08 input port of LoaMgr will remain disconnected.  There is no upstream function to send this signal into LoaMgr. 

   • –Fault may be active because the threshold calibration value is set too high.  For a single-inverter design, threshold cal should be zero.  For a dual-inverter design, threshold cal should be zero or one. 

   • –Fault may be active because LoaMgr input port was not stubbed out with the correct Initial Value.  Should be stubbed with a value of 2.