834 – AL Gas Line Warning
Cause
Corrective action
Emission fault summary alarm
1. Observe additional messages.
2. Contact Service.
835 – AL Gas Line Fault
Cause
Corrective action
Emission fault summary alarm
1. Observe additional messages.
2. Contact Service.
839 – AL EASF A Not Closed by ECU.
Cause
Corrective action
The emergency-air shutoff flap
on the A-side is closed without it
being activated by the ECU. With
the engine running, the signal
also trips closing of the B-side
flap if it is open.
1. Check engine wiring (→ Page 160).
2. Contact Service.
840 – AL EASF B Not Closed by ECU.
Cause
Corrective action
The emergency-air shutoff flap
on the B-side is closed without it
being activated by the ECU. With
the engine running, the signal
also trips closing of the A-side
flap if it is open.
1. Check engine wiring (→ Page 160).
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 160).
2. Check NOx sensor, replace if necessary (→ Page 166).
3. Contact Service.
871 – AL NOx ATO1 communication loss
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 160).
2. Check NOx sensor, replace if necessary (→ Page 166).
3. Contact Service.
872 – AL Flap Egr A Ref learn failed
Cause
Corrective action
Fast reference run of EGR
shutoff flap (M53) (executed
after each ECU restart) faulty.
1. Check charge state of the batteries (plant side).
2. Check operation of EGR shutoff flap (→ Page 122).
3. Contact Service.
MS150096/03E 2015-04
| Troubleshooting | 65
TIM-ID: 0000029153 - 010
