MTU 20V4000C55, Operating Instructions Manual

Page: 70 / 226

834 – AL Gas Path Warning
Cause Corrective action
Emission fault summary alarm 1. Check for additional messages.
2. Contact Service.
835 – AL Gas Path Fault
Cause Corrective action
Emission fault summary alarm 1. Check for additional messages.
2. Contact Service.
857 – AL NOx ATO1 Sensor Defect
Cause Corrective action
The NOx sensor (B88) in the
exhaust line after LP
turbocharger, B side, supplies
incorrect signal or no signal. 1. Check engine wiring (→ Page 158).
2. Check NOx sensor and replace as necessary (→ Page 164).
3. Contact Service.
871 – AL NOx ATO1 Communication Lost
Cause Corrective action
The ECU can no longer detect the
NOx sensor (B88) after LP
turbocharger, B side, on the bus. 1. Check engine wiring (→ Page 158).
2. Check NOx sensor and replace as necessary (→ Page 164).
3. Contact Service.
872 – AL EGR FlpA Wear Limit3
Cause Corrective action
Fast reference run of EGR shutoff
flap (M53) faulty (executed after
every ECU restart). 1. Check state of charge of batteries (plant side).
2. Check operation of EGR shutoff flap (→ Page 113), (→ Page 159).
3. Contact Service.
877 – AL Bypass FlpA Wear Limit3
Cause Corrective action
Fast reference run of bypass flap
(M52) faulty (executed after every
ECU restart). 1. Check state of charge of batteries (plant side).
2. Check operation of bypass flap (→ Page 113), (→ Page 159).
3. Contact Service.
879 – AL Dispenser Flp Wear Limit3
Cause Corrective action
Fast reference run of dispenser
flap (M55) faulty (executed after
every ECU restart). 1. Check state of charge of batteries (plant side).
2. Check operation of dispenser flap (→ Page 113), (→ Page 159).
3. Contact Service.
70 | Troubleshooting | MS15043/00E 2016-04
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