B131 B131 pump unit valve cyl 1: symptoms, fault codes and OEM cross references.
Cylinder 1 unit pump solenoid group for DAF DMCI/EUP systems. Intended for searches by B131, P0201, P0261, P0262 and related pump-unit assembly numbers.
What drivers and mechanics usually notice.
These are practical, workshop-style symptom phrases written for search and support conversations. They are not a substitute for live diagnostic data.
Engine misfire on cylinder 1
Rough idle and vibration
Engine refuses to start or stalls immediately
Cylinder 1 contribution low
Hard hot start and white haze for a few seconds
Why B131 usually fails
- Solenoid winding short or open circuit after heat-cycle fatigue.
- ECU pin or harness short to ground or supply.
- Low-pressure gear pump wear sends metal debris into high-tolerance pump elements.
- Mechanical pusher wear, nozzle clogging or valve gap outside range.
Before replacing the part
- Check gear/lift pump debris before replacing expensive injectors or unit pumps one by one.
- Confirm wiring resistance at ECU and at the cylinder connector hot and cold.
P-codes reported with B131.
| Code | Lookup hint | Related symptom area |
|---|---|---|
| P0201 | Cylinder 1 injector or pump-unit control circuit | Engine misfire on cylinder 1 |
| P0261 | Cylinder 1 pump/injector control circuit low | Engine misfire on cylinder 1 |
| P0262 | Cylinder 1 pump/injector control circuit high | Engine misfire on cylinder 1 |
| P0263 | Cylinder 1 contribution / balance issue | Engine misfire on cylinder 1 |
| P1230 | Cylinder 1 pump-unit contribution / control report | Engine misfire on cylinder 1 |
| P2147 | Injector/pump-unit group supply low or short report | Engine misfire on cylinder 1 |
| P2148 | Injector/pump-unit group supply high or short report | Engine misfire on cylinder 1 |
All numbers grouped under the canonical B131 page.
Keeping every duplicate and replacement number visible on the same canonical page helps exact OEM searches without creating hundreds of duplicated pages.
Truck, engine and year ranges from the reports.
| Truck model | Engine | Years | HP |
|---|---|---|---|
| XF 95 | PACCAR XE/MX Euro 3 | 2001-2006 | 380-530 |
| XF 105 | PACCAR MX Euro 3/4/5 | 2005-2013 | 360-510 |
| CF 75 | PACCAR PR Euro 3/4/5 | 2001-2013 | 250-360 |
| CF 85 | PACCAR MX Euro 3/4/5 | 2001-2013 | 340-510 |
Fitment is structured from user-provided reports and must be verified by VIN, installed connector and physical part markings before supply.
Questions about B131.
What are common failure symptoms for B131?
Common symptoms include Engine misfire on cylinder 1; Rough idle and vibration; Engine refuses to start or stalls immediately; Cylinder 1 contribution low. Exact symptoms vary by truck, software level and related faults.
Which fault codes are linked with B131?
Reported fault codes include P0201, P0261, P0262, P0263, P1230, P2147, P2148.
Can I order by OEM number B131 only?
Use the OEM number as a starting point, then confirm by VIN, engine type, installed connector and part photos because some reports contain duplicate or conflicting OEM references.
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