Theory Of Operation

WARNING: This page is about a different variant/trim than selected.

The Powertrain Control Module (PCM) monitors the Diesel Exhaust Fluid (DEF) for quality after every refill event. A refill event means inserting more than one gallon of DEF into the DEF tank. The PCM will not run another monitor (for this DTC) until the next refill event. This DTC will only be active during the drive cycle when the DTC is actually setting. The DTC will remain in 'stored' status for the next 39 key cycles. A message will be displayed on the Electronic Vehicle Information Center (EVIC): "Service DEF System - See Dealer Soon".

This DTC will no longer be displayed after 40 key cycles. But, the Selective Catalyst Reduction (SCR) Inducement message ("Service DEF System - See Dealer Soon") will continue to display periodically until the SCR Healing Procedure is performed so the monitor runs again. There may be repairs made per other system DTCs (shown below). There may be repairs recommended per this DTC. Or, there may be no repairs indicated at all. All scenarios must end with the SCR Healing Procedure (shown in P2BA9-00-Test Step 7).