FITMENT:
Compatible with Volvo Trucks Euro 5 / Euro 6 vehicles, including:

• FH series (FH12, FH13, FH16, FH500)
• FM series (FM9, FM12, FM13, FM500)
• Selected FL / FE heavy-duty variants (depending on SCR setup)

OEM / Cross reference numbers:

• 21984358
• 5WK9 6717A / 5WK96717A
• 20873395 / 22219283 / 22827993 (common interchange references)

Used in diesel exhaust aftertreatment system for NOx monitoring (SCR / AdBlue system). It is typically configured as post-catalyst (outlet) NOx sensor in Volvo Euro 5/6 SCR systems.

FUNCTION:

• Measures nitrogen oxide (NOx) levels in exhaust gases
• Sends data to ECU for AdBlue dosing control
• Ensures SCR catalyst efficiency
• Maintains Euro 5 / Euro 6 emission compliance

INSTALLATION POSITION:

• SCR system downstream (outlet / post-catalyst sensor)
• Mounted on exhaust pipe after SCR catalytic converter

FAQ:

Q1: Is this inlet or outlet sensor?
A1: This part (21984358 / 5WK96717A) is commonly used as the outlet (post-catalyst) NOx sensor on Volvo FH/FM SCR systems.

Q2: What trucks does it fit?
A2: Volvo FH and FM series Euro 5/6 trucks, especially FH500 and FM500 models with SCR systems.

Q3: What are failure symptoms?
A3: SCR warning light, engine derate, incorrect NOx readings, AdBlue system faults, or limp mode.

Q4: Are all 21984358 sensors interchangeable?
A4: No. Even with the same base number, calibration and connector variants differ (A/B versions).

Q5: Does replacement require programming?
A5: Some Volvo models require diagnostic reset or SCR adaptation after installation.