LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chrysler >> 1999 >> LHS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> System Diagnostic System >> On-Board Diagnostics >> Non-Monitored Circuits
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Non-Monitored Circuits

PCM does not monitor all circuits, conditions and systems that could cause a malfunction or driveability problem. However, problems with these systems may cause PCM to store DTCs for other systems or components.

As an example a fuel pressure problem (clogged fuel filter or pinched fuel line) will not identify a fault directly, but could cause a rich/lean condition or misfire. This could also cause PCM to store an oxygen sensor DTC. The major non-monitored circuits are identified below: