NOx Sensor A / B Correlation
The HINO-P220B (Hino) diesel fault code means: NOx Sensor A / B Correlation. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- intermediate
- Estimated cost
- $500-$2,800
Down with a Hino fault on the road?
Get connected with a verified mobile diesel mechanic near you. Verified diesel & reefer techs, launching on the freight corridor.
Find a mobile mechanic →A $30 car code reader can't do diesel. The HD7000 reads full-system codes and does parked DPF regen, idle/speed-limit, and service resets from the cab — on everything from a 6.7 Cummins/Power Stroke/Duramax pickup to Class-8 trucks (Detroit, Paccar, CAT, Volvo, Mack, International).
Full-system 6/9/16-pin diesel scan tool for Cummins, Paccar, CAT, Detroit and more — plug-and-play, no subscription. A cheaper way to read heavy-duty codes a basic OBD2 scanner skips entirely.
Affiliate links — we earn a commission at no extra cost to you.
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
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 (Hino DX3 / DX4) before replacing any parts.
Can I drive my Hino truck with P220B?
Short runs may be possible but do not ignore — 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?
Estimated 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.
Mechanics Guide Step-by-step diagnosis
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.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
- SAE J2012Diagnostic Trouble Code Definitions (defines P220B as a generic OBD-II code)
P220B on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
Commonly Affected Vehicles
- Hino 155 / 155h with J05 5.1L
- Hino 195 / 195h (hybrid) with J05D 5.1L
- Hino 258 / 258LP / 268 with J08 7.7L
- Hino 338 / 338CT with J08 7.7L
- Hino 358 / 358CT (post-2019 J-series / A09C)
- Toyota Dyna / Hino-branded export chassis with J05/J08
Explore More
Was this helpful?
Send this to whoever is fixing the truck — your tech, or the person asking what the fault means.