FAQ
TL;DR: Forum cases show a repeating pattern: after restart, some Jumper 2.2 HDi vans run fine for up to 100 km, then lose power; one user reports, "He throws me a Check Engine and the car loses power." [Elektroda, radosek, post #18258767]
Why it matters: This FAQ helps Citroën Jumper/Boxer/Ducato owners and techs quickly isolate no‑power faults that mimic limp mode.
Quick Facts
- Symptom cycle: normal power after restart, sometimes lasting ~100 km before another cut. [Elektroda, radosek, post #18258767]
- Edge case: a broken left‑front ABS/speed sensor wire killed power and the speedometer; soldering the wire restored both. [Elektroda, adrbis2, post #16786715]
- Dashboard may show only the handbrake lamp while power is limited; speedometer can read zero. [Elektroda, adrbis2, post #16781788]
- Fast diagnosis: log common‑rail pressure, boost, and MAF during a road test to see the fault live. [Elektroda, Doktorr, post #16782192]
- Quick checks suggested by members: verify EGR vacuum control, momentarily unplug MAF, and inspect intake leaks. [Elektroda, ptr92, post #16784236]
What causes sudden power loss that clears after a restart?
Owners report a transient limp condition: the van pulls well for a minute or after a restart, then an error returns and power drops. That pattern points to a sensor or control signal that goes out-of-range under load, not a permanently failed turbo. Capture live data at the exact moment power falls to see which parameter deviates. [Elektroda, adrbis2, post #16782886]
Can a broken ABS or wheel speed sensor wire really kill engine power?
Yes—one solved case showed a severed left‑front wheel speed sensor wire. The van had poor climb performance and a dead speedometer; soldering the wire restored full power and speed readout. “Such a small matter and so much damage.” This links vehicle speed input to engine torque management on this platform. [Elektroda, adrbis2, post #16786715]
Why did my speedometer die at the same time the van lost power?
In the solved case, the speedometer read zero because the wheel speed signal was missing. The engine then acted like it was in a power‑limited state. Repairing the speed sensor wiring brought back the speedometer and normal acceleration. Braking feel also improved after the fix. [Elektroda, adrbis2, post #16788474]
Which live data should I log on a road test to pinpoint the fault?
Log common‑rail (CR) pressure, boost pressure, and mass‑airflow (MAF) during a full‑throttle pull where the fault occurs. Compare commanded vs. actual values at the exact second power drops. A competent shop can do this quickly and reliably in one session. [Elektroda, Doktorr, post #16782192]
Do ABS faults by themselves put the ECU into limp mode on a Jumper?
One member asserts, “ABS and lack of power have nothing to do,” arguing a broken ABS circuit shouldn’t limit engine torque. However, the thread’s fix shows at least one case where restoring the wheel speed signal coincided with full power return. Treat ABS inputs as part of diagnosis. [Elektroda, ptr92, post #16786908]
What quick checks can I do for EGR or MAF related limp?
Verify the EGR vacuum line and its solenoid don’t leak. Temporarily unplug the MAF to force a default airflow value, then test drive. Also check the intake tract for leaks. If power improves with MAF unplugged, suspect the sensor or air leaks. Reconnect after testing. [Elektroda, ptr92, post #16784236]
The dash only shows the handbrake light—can the engine still be in a reduced‑power state?
Yes. The original poster noted no warning lamps except the handbrake while the van struggled to exceed ~100 km/h and the speedometer was dead. Don’t rely on the MIL alone; scan the engine ECU for active and stored faults during the event. [Elektroda, adrbis2, post #16781788]
What does “CR pressure” mean and why does it matter here?
CR stands for common‑rail fuel pressure. During limp events, compare commanded vs. actual CR to see if fueling collapses under load. A healthy system tracks commands tightly; a large drop suggests supply, pump control, or sensor issues rather than turbo failure. Road‑test logging is essential. [Elektroda, Doktorr, post #16782192]
How do I do a quick driveway check of a front wheel speed sensor circuit?
- Safely lift the front, remove the suspect wheel (often left‑front in the case here).
- Inspect the sensor lead for breaks near the hub; gently tug and look for green corrosion.
- Repair the break (solder/heat‑shrink) and secure the harness, then road test to confirm speedometer and power return. [Elektroda, adrbis2, post #16786715]
Could earlier overheating cause lasting low power?
Yes. A member warned that repeated overheating can reduce compression, causing chronic low power regardless of sensors. If the van overheated, add a compression test and cylinder leak‑down to your plan before replacing parts. “Maybe… there is simply no compression.” [Elektroda, Doktorr, post #16782192]
Is it safe to keep driving long distances before fixing the fault?
It’s unwise. The OP described a 20‑hour, 1,300 km trip as a “disaster” due to limited power, heat stress, and driveability risk. Continuing like this can mask root causes and strain components. Fix the underlying fault before another long haul. [Elektroda, adrbis2, post #16781788]
Why does power return for a minute after startup, then drop again?
This behavior suggests a control system that initializes normally, then flags a fault once a threshold or plausibility check fails under load. The ECU reduces torque to protect hardware. Capturing live data at the fault moment is key. [Elektroda, adrbis2, post #16782886]
Which questions should I ask my shop to speed up diagnosis?
Ask for a monitored road test with logs of CR pressure, boost, and MAF at WOT; confirmation of EGR vacuum control; wheel speed sensor status; and a compression test if overheating occurred. Choose a workshop with proven PSA/Fiat light‑commercial experience. [Elektroda, Doktorr, post #16782192]
Should I clear codes first or repair wiring then clear?
Repair the evident fault, then clear codes, and perform a monitored drive cycle. In the case here, fixing the sensor wire immediately restored power and cleared related symptoms without chasing other parts. Verify with a post‑repair scan. [Elektroda, adrbis2, post #16786715]
What is OBD and why is this van said to be “great at OBD”?
OBD is onboard diagnostics. Members note the Jumper exposes rich live data through OBD, which makes root‑cause identification fast with a capable interface and technician. Use that strength to see what the ECU sees when power drops. [Elektroda, kortyleski, post #16784193]
