HINO-P220B moderate Hino ›

NOx Sensor A / B Correlation

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Can I Drive?

Yes, But Fix Soon

DIY Difficulty

intermediate

Estimated Cost

$500-$2,800

What does HINO-P220B mean?

The HINO-P220B (Hino) diesel fault code means: NOx Sensor A / B Correlation. This is a moderate severity code.

Common Symptoms

DEF warning + progressive derate to 5 mph
No-restart inducement when derate timer expires
Frequent DEF refills / high consumption
Crystalline deposits around DEF doser
High NOx in live data

Probable Causes (Ranked by Likelihood)

Failed NOx inlet or outlet sensor (Hino NOx service life 150K-250K mi) Very Likely
Crystallized DEF at doser from short trips / no-heat soak Likely
DEF pump module motor failure Possible
Contaminated or aged DEF (past 12-24 mo) Possible
Exhaust leak upstream of SCR creating false NOx ratio Possible

Step-by-Step Diagnostic Procedure

Confirm P220B on Hino DX3 or DX4. Capture NOx inlet / outlet live, DEF dosing state, and reductant pressure.
Refractometer-test DEF; must be 32.5% urea ± 1%. Below 30% = replace fluid.
Command DEF pump pressure build. Target pressure must be reached within spec time; inspect pump seals and motor if not.
Inspect DEF doser tip for white crystalline build-up. Remove, soak in warm distilled water, blow out, reinstall.
If NOx sensor live data shows sluggish response or stuck values, replace sensor(s) — often both fail together.

Frequently Asked Questions

What does Hino code P220B mean?

Hino diagnostic trouble code P220B (NOx Sensor A / B Correlation) is a moderate-severity fault on Hino medium-duty diesel engines. It indicates a problem in the SCR / DEF system that should be verified with a scan tool (Isuzu IDSS / Tech2 for Isuzu, Hino DX3 / DX4 for Hino) before replacing any parts.

Can I drive my Hino truck with P220B?

Short runs may be possible but do not ignore — Isuzu and Hino medium-duty aftertreatment faults cascade quickly into 5-mph derate or no-restart. Schedule diagnosis immediately.

How much does it cost to fix Hino P220B?

Typical repair cost runs $500-$2,800. Sensor, wiring, and DEF-related repairs fall at the low end; DPF service, turbo, injector, and EGR cooler work fall at the high end and may require dealer-level programming.