FAQ
TL;DR: 30°C heat can trigger MCM 660012; "my 1845 Actros makes a mistake when the weather temperature is over 30 degrees Celsius." This FAQ helps Actros MP4 owners fix motor flash and power loss from code 660012 with clear checks and field‑tested fixes. [Elektroda, ariateline, post #20077773]
Why it matters: It cuts downtime and avoids needless parts swaps by prioritising checks you can do fast, on-road or in-shop.
Quick Facts
- Code MCM 660012 with sensor B608 was reported as turbocharger‑related; replacing the turbo cleared the fault. [Elektroda, aliveratrans, post #20056031]
- Venturi tube location: front of engine, sensor on top; remove the sensor and clean the small orifice. [Elektroda, citromaniak, post #20303728]
- Heat sensitivity noted above 30°C; turbo pressure control unit A0001531559 suspected when hot. [Elektroda, ariateline, post #20077773]
- AdBlue over‑injection clogged the muffler/DPF; cleaning restored power and cleared errors. [Elektroda, Arti04, post #20303393]
- Under steep climbs, ECO mode reduced the fault occurrence for one driver. [Elektroda, Adrian.86, post #17385593]
What symptoms go with MCM 660012 on an Actros MP4?
Typical symptoms include a flashing engine warning, slight power loss, and MCM 660012 shown on the display. [Elektroda, Andik1313, post #17337660]
Does switching to ECO mode help when 660012 appears uphill?
Yes. One driver reports the engine light during hard climbs and that “Switching from normal to Eco driving mode helps.” It’s a temporary workaround under load. [Elektroda, Adrian.86, post #17385593]
What is the Venturi tube and where is it on the MP4?
It’s an intake Venturi with a small sensing orifice. “The venturi tube is at the very front of the engine, the sensor is screwed into it from the top.” Cleaning the orifice can restore readings. [Elektroda, citromaniak, post #20303728]
How do I clean the Venturi tube to try clearing 660012?
Three steps:
- Locate the front‑of‑engine Venturi and remove the top‑mounted sensor.
- Clear the small sensing hole/orifice of soot deposits.
- Refit the sensor, clear the code, and road‑test under load. [Elektroda, citromaniak, post #20303728]
Did replacing the Venturi tube actually fix this code for anyone?
Yes. One owner states, “the Venturi tube is replaced and the problem is gone.” Cleaning is a quicker first try, but replacement also works. [Elektroda, Andik1313, post #17386793]
Which tube should I look at—EGR pipe or turbo pipe?
Focus on the Venturi tube at the very front of the engine with the sensor on top. That’s the piece people clean or replace. [Elektroda, citromaniak, post #20303728]
I replaced boost and turbo sensors and still have 660012. What next?
Try cleaning or replacing the Venturi tube. A member reports sensors and turbo work did nothing, while Venturi cleaning resolved the fault. [Elektroda, Tiromaniak, post #20054775]
Could the turbocharger itself be the cause of 660012?
Yes. One report says replacing the turbo cleared MCM 660012 and sensor B608 faults. Verify boost control and mechanical condition before replacement. [Elektroda, aliveratrans, post #20056031]
Why did 660012 return two weeks after a new turbo?
One owner had the code return after two weeks and considered replacing related tubes next. Inspect piping near the turbo and EGR paths. [Elektroda, aliveratrans, post #20074558]
Can heat or the turbo pressure control unit trigger intermittent 660012?
Heat can matter. “My 1845 Actros makes a mistake when the weather temperature is over 30 degrees Celsius.” The pressure control unit A0001531559 was suspected. [Elektroda, ariateline, post #20077773]
Could AdBlue or DPF issues cause similar power loss and codes?
Yes. An over‑injecting AdBlue system clogged the muffler/DPF. After cleaning, performance and errors normalized. Check dosing and backpressure if regens spike. [Elektroda, Arti04, post #20303393]
Should I check NOx sensors or the AMC module if regens are frequent?
Yes. One tech notes the AMC can affect EGR control. Verify NOx sensor data first when DPF regenerations become unusually frequent. [Elektroda, ariateline, post #20075981]
Can an ECU software update resolve stubborn 660012 cases?
It can. A member fixed the error after months by updating engine computer software: “now everything is wonderful.” Use professional flashing tools. [Elektroda, elawar80, post #20583305]
Is it normal for diagnostics to show little besides 660012?
It happens. One driver saw the fault during climbs, but “Nothing showed on the website.” Capture live data under load to catch it. [Elektroda, Adrian.86, post #17385593]
