Adblue Alarm Calorie-Free On (Fixed)

Volvo FL AdBlue Fault

A Volvo truck was presented to our workshop today, the driver had reported a fault that the musical instrument cluster was showing a alarm for AdBlue organization failure. 

Naturally the offset activity to induce got was to ship out a diagnostic code read. However when nosotros attempted to code read the AdBlue command module (ECU) it was establish to endure non communicating.

Instead carrying out a fault code read of the engine command unit of measurement was establish to endure useful, hither are the results:

• MID(128):Injection ECU, PSID:229, FMI (9):Data update frequency

• Connection employment alongside the UDS (AdBlue heart module) ECU on the SAE J1939 CAN motorcoach information line.

It became apparent that the AdBlue organization was non accessible due to a CAN motorcoach fault. 

The side past times side footstep was to monitor the CAN network at the AdBlue ECU. As nosotros explained inwards our previous CAN fault finding article, nosotros offset exam the CAN network alongside the wiring block disconnected from the AdBlue ECU. The oscilloscope was setup every bit follows:

• Channel Influenza A virus subtype H5N1 / 1 - 5vDC
• Channel B / 2 - 5vDC
• Timing - fifty nano seconds

Here is the waveform every bit viewed on the oscilloscope:

Good CAN Signal AdBlue System

As you lot tin say alongside the ECU disconnected the CAN network behaves every bit expected (equal as well as contrary traces betwixt the CAN High as well as CAN Low). Next nosotros reconnect the wire to the ECU as well as cash inwards one's chips on to monitor the CAN betoken alongside the oscilloscope, i time to a greater extent than hither are the results:

Bad CAN Signal AdBlue System

It is clear that alongside the AdBlue ECU connected at that spot is a definite fault alongside the CAN signal. Most notably on the cerise CAN Low line. This suggests that the fault lies inside the ECU as well as non the wiring.

Next nosotros removed the ECU from the AdBlue module as well as proceeded to opened upward the ECU to come across if at that spot was whatever visible corrosion or burnt components. 

We establish corrosion as well as a burnt constituent on the circuit board, hither is an icon of the burnt component: 

Blown Component Between Pins

We proceeded to lodge a novel AdBlue heart as well as ECU module, i time received it was fitted the fault codes cleared as well as the the vehicle route tested. All was proficient the fault was fixed as well as the vehicle returned to the customer.

Hopefully this article helps you lot to diagnose CAN network faults as well as attain upward one's heed if the fault is inwards the wiring or ECU.

Why non exit a comment if you lot induce got had a like experience.