FAQ
TL;DR: DAF XF 105.460: 5 bar idle fuel pressure is normal; "EBS will not reduce power." Intermittent warnings often trace to filters, feed-pump pressure, or a faulty fuel temp/pressure sensor. [Elektroda, serwis33, post #16702709]
Why it matters: This FAQ helps drivers and fleet techs quickly diagnose power-loss warnings on long routes with practical, road-tested steps.
- Typical idle fuel supply pressure ≈ 5 bar; verify with a manometer at the sensor port. [Elektroda, serwis33, post #16702709]
- Pump failure sign: pressure “jumps” 1–2–3 bar at idle instead of holding steady. [Elektroda, szy18, post #16713805]
- New fuel temp/pressure sensors can be defective; DAF accepted multiple complaints. [Elektroda, serwis33, post #16713205]
- Non‑original filters caused restriction; OEM DAF filter + separator resolved warnings. [Elektroda, Kazor26, post #16732886]
- EBS faults do not derate engine power on this platform. [Elektroda, serwis33, post #16702709]
Quick Facts
- Typical idle fuel supply pressure ≈ 5 bar; verify with a manometer at the sensor port. [Elektroda, serwis33, post #16702709]
- Pump failure sign: pressure “jumps” 1–2–3 bar at idle instead of holding steady. [Elektroda, szy18, post #16713805]
- New fuel temp/pressure sensors can be defective; DAF accepted multiple complaints. [Elektroda, serwis33, post #16713205]
- Non‑original filters caused restriction; OEM DAF filter + separator resolved warnings. [Elektroda, Kazor26, post #16732886]
- EBS faults do not derate engine power on this platform. [Elektroda, serwis33, post #16702709]
What usually triggers “engine warning” and power loss on a DAF XF 105.460?
Most cases trace to fuel supply issues: restricted filters, unstable feed‑pump pressure, or a faulty combined fuel temperature/pressure sensor. EBS faults do not cause power reduction here. Start by confirming a steady ~5 bar at idle and inspecting filters. [Elektroda, serwis33, post #16702709]
How do I check fuel pressure correctly on this engine?
- Remove the fuel pressure sensor and tee in a calibrated manometer.
- Start and observe idle pressure; target about 5 bar steady.
- Blip the throttle; pressure should remain stable, not swing 1–3 bar. [Elektroda, serwis33, post #16702709]
What is the normal fuel pressure at idle for the DAF 105 460?
Expect about 5 bar at idle. The reading should hold steady, both at idle and with light throttle inputs, when measured with a mechanical gauge at the sensor port. [Elektroda, serwis33, post #16702709]
Does an EBS error reduce engine power on the DAF 105?
No. As one expert put it, “EBS will not reduce power.” Power loss warnings in this thread tied back to the fuel system rather than the braking electronics. Focus diagnosis on filtration, feed pressure, and the dual temp/pressure sensor. [Elektroda, serwis33, post #16702709]
My new fuel temp/pressure (duplex) sensor still throws errors—can it be bad?
Yes. Multiple brand‑new sensors were reported defective and replaced under complaint. Swap in a known‑good sensor from another truck to A/B test before chasing wiring faults. Intermittent on/off errors while driving match this failure mode. [Elektroda, serwis33, post #16713205]
When should I replace the feed pump?
Replace it if pressure can’t hold near 5 bar at idle or “wavers” in the 1–3 bar range. A steady 5 bar indicates the feed pump is healthy and does not need replacement. Verify with a mechanical gauge rather than only scan‑tool data. [Elektroda, serwis33, post #16702709]
What are the symptoms of a failing feed pump on high‑mileage units?
At around 950,000 km, users reported low‑fuel‑pressure warnings 2–3 times per week, with idle pressure jumping between 1 and 2 bar. After replacing the pump, idle pressure returned to 4–5 bar and faults stopped. [Elektroda, szy18, post #16713805]
Can aftermarket fuel filters really cause derate or warnings?
Yes. One owner fixed recurring warnings by replacing non‑original filters and the separator with OEM DAF parts. Different media bandwidth can restrict flow and trigger low‑pressure faults under load. Use OEM filtration on this platform. [Elektroda, Kazor26, post #16732886]
What is the “Christmas tree” in the fuel filter housing and should I check it?
It refers to a plastic insert/stack in the filter housing. If damaged, it can affect fuel flow or sealing. Inspect it during filter service when diagnosing pressure anomalies or intermittent power loss. Replace if compromised. [Elektroda, serwis33, post #16702709]
Could debris in the fuel tank cause intermittent power loss?
Yes. A small plastic piece in the tank blocked fuel intermittently on one truck, causing severe performance issues without clear ECU faults. Inspect the tank with a lamp and remove any floating debris. [Elektroda, serwis33, post #16713205]
DMCI shows no errors—what should I do next?
Software can miss intermittent supply faults. Perform live tests with DAVIE or a capable tool, including cylinder performance and fan tests, while monitoring mechanical gauge pressure to correlate events. [Elektroda, serwis33, post #16706619]
What diagnostic tools are mentioned (Jaltest, DAVIE), and what do they do?
Jaltest and DAVIE are multi‑system diagnostic platforms used to read faults and run tests. In this thread they were used to view live fuel pressure, run road tests, and perform fan/cylinder checks during diagnosis. [Elektroda, serwis33, post #16706619]
How do I differentiate a sensor fault from a real pressure problem?
If a mechanical gauge shows steady ~5 bar while the ECU logs pressure/temperature faults, suspect the duplex sensor. Quote: “If it keeps ‘rigid’ the sensor is damaged.” Swap with a known‑good unit to confirm. [Elektroda, serwis33, post #16706619]
What quick fixes helped others clear the warning on long routes?
Replacing non‑OEM filters with original DAF filter and separator restored normal operation and stopped warnings. Ensure all fuel‑line connections are tight and air‑free after service before testing under load. [Elektroda, Kazor26, post #16732886]
Any edge cases to remember during diagnosis?
A brand‑new duplex sensor may be faulty out of the box, and debris in the tank can intermittently starve the system without stored DMCI errors. Check both before authorizing major parts. [Elektroda, serwis33, post #16713205]
Should I rely only on scan‑tool readings for fuel pressure?
No. Validate with a calibrated manometer at the sensor port. Scan‑tool values can mislead when the sensor itself is failing or drifted. Trust the mechanical reading for decisions. [Elektroda, serwis33, post #16702709]
