PACCAR MX (2004 Emissions) Fault Code: P170E NOx Sensor Before Catalyst Response – Incorrect

PACCAR MX (2004 Emissions) Fault Code: P170E NOx Sensor Before Catalyst Response – Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that measured engine NOx emissions differ too much from the expected engine NOx emissions during transient operation of the engine (expected decrease of NOx emissions).

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When the engine is running at a steady load and its speed is between 1200 and 1700 rpm and
2. The coolant temperature is above 50°C [122°F] and
3. The engine mode is DOC heating or DPF regeneration or SCR heating or SCR high efficiency or standard or protection and
4. The NOx sensor before catalyst (F844) is in the operating mode

CORRESPONDING OBD READINESS MONITOR:
Exhaust gas sensors monitor

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the following conditions:
– Corresponding readiness monitor displays ‘Ready’
– Diagnostic conditions are met
– Set conditions are met
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
NOx sensor before catalyst deviation

ADDITIONAL INFORMATION:
1. The measured engine NOx emissions are compared with the expected engine NOx emissions during transient operation of the engine.
2. The engine NOx emissions are measured by the NOx sensor before catalyst (F844).