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PEUGEOT BOXER III - Repair of the AdBlue tank PEUGEOT BOXER III, CITROEN JUMPER

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Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
  • #241 21860422
    piotrnowinski
    Level 3  
    Amazing job, full reverse engineering. Super that you managed to write down so much useful information.
    I have just pulled the tank off after the P20E8 fault (Peugeot Boxer III). I have tested everything, obviously the thermistor on the heating plate is faulty (400 ohm).
    Thermistor already ordered.

    While pulling the tank I measured the resistance on the heater plug of the wire to the injector, it looks like there is a break. Can anyone have an idea of when this circuit is checked by the controller? Is there a possibility that until winter comes I won't see the error? Is it possible to replace this heater with some kind of resistor, if so, what kind?
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  • #242 21860971
    Reflekt
    Level 17  
    the system diagnoses itself and, if there is a break in the heating system, it would indicate this with a message on the dashboard, or perhaps it is not the thermistor but the heater that has gone wrong.
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  • #243 21860982
    piotrnowinski
    Level 3  
    The thermistor is 400 ohm and does not respond to temperature change. It looks like there are two faults, but I wonder if the external heater to the injector is always tested and if the system will trip if there is a break in this heater.
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  • #244 21861098
    Reflekt
    Level 17  
    is tested by the system, plug in the didgibox and see what adblue hurts.
  • #245 21861181
    piotrnowinski
    Level 3  
    I checked with Launch, only one error P20E8 (low AdBlue pressure). After clearing the error and turning the ignition, you can hear the pump come on and initially there is no error. Pressure 4 bar (i.e. none), urea temperature 0°C, Operating Status Of The Denox System: Pump Stopped Empty. After driving a few kilometres, when it comes to AdBlue, the error appears, while nothing changes in the parameters. It looks as if there are some default parameters on the ECU that are not being updated, which is probably because the AdBlue is cut off early on. A couple of things are unclear to me: if a test is done when the ignition is turned, why does the error not appear immediately but only after some time, is this always the case or does it depend on the fault. The second thing is: if the ignition is turned on, should the pump build up a pressure of more than 4 bar? Does the pressure only build up while driving? And one more thing: if an error appears on the dashboard, there is no error in the ECU when I connect the interface, only I have to drive around a bit more and the message "Engine error" appears, and only then can I see the error in the ECU - is this normal?
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  • #246 21861188
    staszek75
    Level 12  
    The urea temperature of 0stC and the resistance of the thermistor indicate that the thermistor is defective. This should be done in the first instance.
  • #247 21862444
    piotrnowinski
    Level 3  
    After replacing the thermistor and putting a 3.3 ohm resistor on the heater circuit of the urea wire (just as a test), unfortunately it still doesn't work. The only thing that has changed is that it now shows the real temperature instead of 0°C. Does anyone know if DiagBox allows you to see some more detailed errors from the AdBlue module itself?

Topic summary

The discussion focuses on the repair and diagnostics of the AdBlue tank system in PEUGEOT BOXER III and CITROEN JUMPER vehicles, addressing common errors such as P20E8 (low urea pressure) and communication faults with the SCR (Selective Catalytic Reduction) system. Key issues include sensor failures (urea level sensor, temperature sensors on the heating plate and heater circuits), pump and solenoid valve malfunctions, and electronic board damage due to urea corrosion. The tank electronics include a microcontroller (R5F21368WKFP), pump driver circuits with an H-bridge allowing bidirectional pump control, and multiple heating circuits to prevent AdBlue freezing. Repair strategies involve visual inspection for leaks and corrosion, testing and bypassing faulty sensors (e.g., using resistor voltage dividers to simulate full tank level), replacing damaged temperature sensors with 10 kΩ thermistors, and verifying heating circuit resistances. The system requires clearing ECU errors via diagnostic tools (DiagBox) after repairs, as error messages do not always clear automatically. Some users report that the system self-bleeds air over driving distance, negating the need for manual bleeding. The pressure sensor model HM8500J is identified as critical for monitoring AdBlue pressure, with detailed testing performed. The discussion also covers the challenges of tank disassembly and repair, recommending plastic welding over gluing due to ABS plastic construction. Some users mention software or ECU programming to disable or neutralize the AdBlue system as a last resort. The importance of proper electrical connections and CAN bus communication is emphasized, as loss of communication leads to power cutoff to the tank electronics after about 30 seconds. Overall, the thread provides detailed technical insights, component specifications, diagnostic procedures, and practical repair tips for maintaining and restoring AdBlue tank functionality in PSA group diesel vehicles.
Summary generated by the language model.
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