EA4-x NTC 0x0AC LoaHwTqIdptSigNrFlt

Nexteer Confidential

LOA Handwheel Torque Indpendent Signals Number Fault Overview
NTC 0x0AC.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 Handwheel Torque Independent Signal represents the currently active number of Handwheel Torque signals.  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. • –An individual handwheel torque sensor is offline, due to being out of range or perhaps a protocol issue.  This should result in an upstream F3 in an ES function. 

   • –A pair or more of sensors do not correlate with one another.  This should result in an additional F3 fault from the upstream ES function: Handwheel Torque Correlation.