NHTSA ID Number: 10170539
Manufacturer Communication Number: LI54.21-P-070658
TSB/Document Date: 2020-01-21
Summary
SRS Message Displayed in Instrument Cluster
SRS Message Displayed in Instrument Cluster
Topic number
LI54.21-P-070658
Version
1
Function group
54.21 Control units / basic modules
Date
12-17-2019
Validity
A-Class (177)
CLA-Class (118)
Reason for change
Reason for block
Complaint:
A fixed SRS message is displayed in the instrument cluster. Cause is not safety-relevant and does not affect function
of safety systems.
Cause:
Higher resistance values at the SRS control unit connector for various SRS components (squibs, tensioners, pyrofuse, etc.). Complaint vehicles contain the stored fault code "There is an open circuit" for various squibs.
Remedy:
Note: If there are active faults or short circuit faults, this document does not apply. Further vehicle diagnosis is required.
Fault-trace wire for affected component and ensure that there is no chafing or damaged areas. Ensure that all
connections are secure and wires are firmly attached to connectors. If the inspection does not find a root cause, proceed with the attached work instructions.
If the SRS Control Unit is erroneously replaced per the attached work instructions, the warranty claim is subject to debit.
Attachments
File
Description
Harness attach to vent.jpg
Figure 1. SRS harness is attached to the AC Vent
SRS CU Q Level 3.jpg
Figure 2. Location of Q-Level
Work Instructions.pdf
Work Instructions
Symptoms
Body / Safety system / Airbag/Supplemental restraint system SRS / Indicator lamp / SRS indicator lamp / lit
Body / Safety system / Seat belt / Seat belt indicator lamp / lit
Body / Safety system / Airbag/Supplemental restraint system SRS / Indicator lamp / Airbag / lit
Control unit/fault code
Control unit
12-19-2019 6:27 PM
© Copyright Mercedes-Benz
AG
Fault code
Fault text
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Page 1/5
N2/10 - Supplemental restraint B000313
system (SRS) (ORC177)
The squib for the vent valve 'Driver airbag' has a malfunction.
There is an open circuit.
N2/10 - Supplemental restraint B003813
system (SRS) (ORC177)
The squib for the right rear sidebag has a malfunction. There is
an open circuit.
N2/10 - Supplemental restraint B001013
system (SRS) (ORC177)
The squib for the front passenger airbag (stage 1) has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B1B3613
system (SRS) (ORC177)
The squib for the emergency tensioning retractor at the center of
the first seat row has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B275013
system (SRS) (ORC177)
The squib for the sidebag 'Driver' has a malfunction. There is an
open circuit.
N2/10 - Supplemental restraint B284F13
system (SRS) (ORC177)
The squib for pyrofuse 'High-voltage on-board electrical system'
has a malfunction. There is an open circuit. (OCM177)
N2/10 - Supplemental restraint B001213
system (SRS) (ORC177)
The squib for the vent valve 'Front passenger airbag' has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B001113
system (SRS) (ORC177)
The squib for the front passenger airbag (stage 2) has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B275113
system (SRS) (ORC177)
The squib for the sidebag 'Front passenger' has a malfunction.
There is an open circuit.
N2/10 - Supplemental restraint B000113
system (SRS) (ORC177)
The squib for the driver airbag (stage 1) has a malfunction. There
is an open circuit. (OCM177)
N2/10 - Supplemental restraint B00E313
system (SRS) (ORC177)
The squib for the left rear emergency tensioning retractor has a
malfunction. There is an open circuit.
N2/10 - Supplemental restraint B008013
system (SRS) (ORC177)
The squib for belt force limiter 'Driver' has a malfunction. There is
an open circuit.
N2/10 - Supplemental restraint B007913
system (SRS) (ORC177)
The squib for the emergency tensioning retractor 'Belt end
fitting' (driver) has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B00E613
system (SRS) (ORC177)
The squib for the emergency tensioning retractor at the right of
the third seat row has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B001313
system (SRS) (ORC177)
The squib for the front passenger kneebag has a malfunction.
There is an open circuit.
N2/10 - Supplemental restraint B00E413
system (SRS) (ORC177)
The squib for the right rear emergency tensioning retractor has a
malfunction. There is an open circuit.
N2/10 - Supplemental restraint B002113
system (SRS) (ORC177)
The squib for the left windowbag/headbag has a malfunction.
There is an open circuit.
N2/10 - Supplemental restraint B007A13
system (SRS) (ORC177)
The squib for the emergency tensioning retractor 'Belt end
fitting' (front passenger) has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B00E713
system (SRS) (ORC177)
The squib for the emergency tensioning retractor at the left of the
third seat row has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B273513
system (SRS) (ORC177)
The squib for pyrofuse 'On-board electrical network line' has a
malfunction. There is an open circuit.
N2/10 - Supplemental restraint B002213
system (SRS) (ORC177)
The squib for the left rear windowbag has a malfunction. There is
an open circuit.
N2/10 - Supplemental restraint B000113
system (SRS) (ORC177)
The squib for the driver airbag (stage 1) has a malfunction. There
is an open circuit.
N2/10 - Supplemental restraint B002A13
system (SRS) (ORC177)
The squib for the right rear windowbag has a malfunction. There
is an open circuit.
12-19-2019 6:27 PM
© Copyright Mercedes-Benz AG
ROTOOLE
Page 2/5
N2/10 - Supplemental restraint B007E13
system (SRS) (ORC177)
The squib for emergency tensioning retractor 'Driver' has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B002913
system (SRS) (ORC177)
The squib for the right windowbag/headbag has a malfunction.
There is an open circuit.
N2/10 - Supplemental restraint B1C1E13
system (SRS) (ORC177)
The "Driver" seat occupancy recognition has a malfunction. There
is an open circuit.
N2/10 - Supplemental restraint B000213
system (SRS) (ORC177)
The squib for the driver airbag (stage 2) has a malfunction. There
is an open circuit.
N2/10 - Supplemental restraint B007F13
system (SRS) (ORC177)
The squib for emergency tensioning retractor 'Front passenger'
has a malfunction. There is an open circuit.
N2/10 - Supplemental restraint B003013
system (SRS) (ORC177)
The squib for the left rear sidebag has a malfunction. There is an
open circuit.
N2/10 - Supplemental restraint B000413
system (SRS) (ORC177)
The squib for the driver kneebag has a malfunction. There is an
open circuit.
N2/10 - Supplemental restraint B008213
system (SRS) (ORC177)
The squib for belt force limiter 'Front passenger' has a malfunction. There is an open circuit.
Parts
Part number
ES1 ES2 Designation
A 177 900 04 04
Quantity Note
CONTROL UNIT, COMPLETE 1
EPC
Not every repair requires replacement. Follow attached work instructions.
X
Operation numbers/damage codes
Op. no.
Operation text
Time
Damage
code
Note
82485 73
Repair type 7 for exercising connector
82485 73
Repair type 1 for replacing SRS CU
Attachments
12-19-2019 6:27 PM
© Copyright Mercedes-Benz AG
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Page 3/5
Harness attach to vent.
jpg:
12-19-2019 6:27 PM
© Copyright Mercedes-Benz AG
ROTOOLE
Page 4/5
SRS CU Q Level 3.jpg:
12-19-2019 6:27 PM
© Copyright Mercedes-Benz AG
ROTOOLE
Page 5/5
If there is a CURRENT
fault code in the SRS CU,
this document is not
valid and should not be
used.
START
Is the SRS harness
secured to AC vent?
See Figure 1
YES
NO
Short circuit faults or
Current open/excessive resistance
faults?
YES
NO
YES
Short circuit faults or
Active open/excessive resistance
faults?
NO
Any faults stored in SRS CU?
Not relevant to this LI
document. Further
diagnose vehicle.
No
Remove & inspect SRS
Control Unit
YES
Disconnect SRS Control Unit.
Inspect for corrosion or cable
strain in connectors
SRS Control Unit
Q1/Q2? See Figure 2
Open PTSS Case with
relevant
documentation.
Exercise connector by dis‐/
reconnecting cable 5 times.
Do not use cleaner
NO
Clear stored faults.
Open PTSS case with
relevant
documentation
YES
Replace SRS Control Unit
and
secure harness. See
Figure 1.
YES
Secure SRS harness
to AC vent. See Figure 1.
SRS Message in IC?
NO
Release Vehicle
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TSB/Document ID: LI54.21-P-070658
Replacement Service Bulletin Number:
MFR Communication Date: 2019-12-17
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL
MFR Component System:
MFR Component Subsystem:
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