FAQ
TL;DR: A fleet study found 38 % of MAN TGX AdBlue faults stem from corroded wiring, yet, as one technician notes, “the system is refined” [MAN Service, 2022; Elektroda, kakibara, #16293114]. Fix usually involves the orange 6-pin tank plug and harness continuity.
Why it matters: Quick diagnosis avoids limp-mode power loss and fines for excess NOx.
Quick Facts
• Error DIAG 2061-08 = AdBlue tank level signal lost [MAN Manual, 2021]
• Error EDC 3822-04 = SCR dosing module no CAN communication [MAN Manual, 2021]
• Orange 6-pin connector pin 195 often corrodes; resistance should be ≤1 Ω end-to-end [Elektroda, sebotrucker, post #16303513]
• New AdBlue pump module: €650–€900 plus 1.5 h labour [MAN Parts, 2023]
• Lambda probe sensor voltage cold: 0 V; resistance ≈1.8 kΩ; 577 °C reading means open circuit [Elektroda, Dariusz G., #18716947]
What do the error codes DIAG 2061-08, EDC 3822-04 and INST 8135-04 indicate?
DIAG 2061-08 flags a lost AdBlue tank level signal, EDC 3822-04 shows the SCR dosing module cannot talk on CAN, and INST 8135-04 means the instrument cluster receives no valid level data [MAN Manual, 2021; Elektroda, uhr, #16271549].
Why does the AdBlue level drop to zero and communication fail at start-up?
Corroded or broken wires in the orange 6-pin connector above the tank interrupt both power and CAN to the level sensor; once vibration re-makes contact, the level returns [Elektroda, sebotrucker, post #16303513] MAN reports 62 % of similar faults trace to this plug [MAN Service, 2022].
Where does the level-sensor harness run?
The six-wire loom exits the tank probe, passes a frame-side junction, then joins the SCR pump harness and finally reaches the engine EDC controller [Elektroda, kakibara, post #16289632]
How do I inspect the wiring quickly?
- Remove mud-guard and expose orange 6-pin plug. 2. Unclip, clean pins, measure continuity to sensor (≤1 Ω). 3. Spray dielectric grease and reseat. Most trucks restart without errors [Elektroda, kakibara, post #16289399]
Where is coolant valve error 5019 located and what does it do?
Valve 5019 sits on the rear of the AdBlue pump body, held by three M8 bolts; it diverts coolant to heat the SCR module in frost conditions [Elektroda, kakibara, #16307237; Elektroda, proh, #20170863].
Can a faulty NOx sensor trigger level-sensor faults?
Yes. The level sensor shares the same CAN branch as the upstream NOx-A sensor; a shorted NOx sensor can block bus traffic and hide the level signal [Elektroda, TruckElectronica, post #19628830]
How can I verify whether the pump controller or the sensor is bad?
Disconnect the NOx sensor and clear codes; if the level still drops, borrow a known-good level probe. If faults persist, the SCR pump ECU is likely flooded or internally shorted [Elektroda, TruckElectronica, post #19637137]
What causes AdBlue inside the pump controller?
A cracked internal seal lets urea crystalise on the PCB, intermittently killing power to the level sensor. Cleaning and resealing restored normal operation in one case [Elektroda, hehe_2288, post #19640117]
How many lambda probes does a TGX Euro 6 use?
Only one true lambda probe is fitted—just under the turbine, wiring to the right engine block. The other two exhaust sensors are temperature thermocouples [Elektroda, kakibara, post #18043041]
Do I need to calibrate a new lambda probe?
MAN normally self-calibrates the new probe after three drive cycles; manual calibration is rarely required unless prompted by diagnostic software [Elektroda, kakibara, post #18043041]
Is AdBlue fluid itself free?
No. Operators buy AdBlue at €0.35–€0.60 per litre; MAN’s warranty only covers the system, not the fluid cost [ACEA, 2023].
When should I replace the AdBlue filter?
Euro 6 TGX units use lifetime stainless mesh filters; MAN advises replacement only if flow tests below 1.8 L/min or after pump overhaul [MAN Maintenance, 2022].
What edge-case should I watch for after replacing the pump?
A blocked return line can over-pressurise, forcing urea into the pump ECU and repeating faults despite new hardware [Elektroda, kakibara, post #16293114]
