Functional Impairment Of 48 V On-Board Electrical System (VERSION 20)

Publication date: 2025-03-25
Reference number: VERSION 20
Supersedes refnos: LI54.10-P-069698

FUNCTIONAL IMPAIRMENT OF 48 V ON-BOARD ELECTRICAL SYSTEM

TECHNICAL SERVICE BULLETIN

Reference Number(s): LI54.10-P-069698 Version 20, Date of Issue: March 25, 2025

MERCEDES-BENZ:	Model series 167, 257, 213, 238, 290 with code B01; Does Not apply to 223 or 206
FUNCTION GROUP:	54.10 - Battery, power supply, voltage converter
REASON FOR CHANGE:	Remedy Change

COMPLAINT

This LI does Not apply to 223 or 206 which use a different generation of 48V systems. Please follow the relevant guided tests for the 223 and 206.

For 223 with fault code B1FCB97 follow LI54.10-P-076026.

Various causes are possible. The faults listed in the various causes do not all have to be present at all times. Some of these complaints may overlap. Rely on the faults listed in the Cause section for identifying the correct Remedy.

No start
Yellow or red instrument cluster message for 48 V on-board electrical system battery (G1/3)
Limp home mode, overheating, A/C not blowing cold, or loss of acceleration
Check Engine Light

CAUSE

Cause 1: Software causes Intermittent No Starts with fault B183387 in DC/DC converter N83/1

Cause 2: Software causes Permanent No Start with fault B183349. May also have fault B183371.

Cause 3: Hardware short circuit in 48V system causes fault B183319 in 48V battery. May also have fault B183371.

Cause 4: Internal 48V battery Peltier cooling element failure causes fault B183397

Cause 5: This will Always have fault code B183371 but different from cause 2 and 3 - it will Not have B183349, B183319, or any other faults in the 48V battery. This will only have fault B183371 in 48V battery. Cause 5 is from the 48V battery detecting an abnormality which then causes the 48V battery to disconnect itself. The disconnected 48V battery then causes subsequent symptoms: Limp Home Mode, overheating, A/C not blowing cold, or loss of acceleration

Cause 6: Check Engine Light with fault P0606F1 in the N127 PTCU

Cause 7: Check Engine Light with possible no start and fault P057FF1

REMEDY

NOTE: each of these remedies correspond to a specific cause. Make sure to match correct Cause with Remedy.

Remedy 1:

Check the 12V power supply and LIN connection
Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons
Road test and release vehicle if no further symptoms

Remedy 2:

Charge the 12V battery (Charging current <5A)
Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons
Road test and release vehicle if no further symptoms

If the faults return or cannot be cleared:

XENTRY MUST be connected with VCI cable to correctly complete this remedy.
Complete guided test for B183349.
If guided test completes, vehicle starts, and drive cycles show no further symptoms, release vehicle.
If after guided test completes, XENTRY states to replace 48V battery: replace only 48V battery. If vehicle is a MY21 w/M256 engine, update SW in 48V battery
If this is a repeat visit for fault B183349 and guided test has already been completed, open a TIPS case.
If guided test does not complete OR symptoms are still present open a TIPS case.
If communication cannot be established with 48V battery perform physical layer check at 12V wiring to DCDC. If no abnormalities found, replace the 48V battery.
If guided test completes but a new fault code is present (such as B183319, B183371, etc.) follow the relevant Cause/Remedy for that fault in this LI.

Remedy for 3:

If fault is not Current (only Stored):
1. Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons
2. Road test and release vehicle if no further symptoms
If the faults return or this is a second visit after the SW update:
1. Complete the guided test for B183319
2. Perform XENTRY actuations for all 48V components.
3. Create a TIPS case with ALL Preliminary measures required as noted below for Remedy 5
4. Upload to TIPS case ISA performance data from the N129.
5. ISA performance data location in XD:
6. N129 control unit under Special Procedures
7. "Procedures for support queries to market support"
8. "Collation of diagnosis performance data"
9. "engine at idle"
10. After next screen loads with data click continue. The next screen will show where the .CSV file is located in your XENTRY. Navigate to this location in XD and upload this CSV file to the case.
11. Note it is important this is a .CSV file extension and Not a screenshot or print of the data values.
If fault is Current AND Stored:
1. Disconnect the 48V battery.
2. Remove terminal 40 on 48V battery to DC/DC converter N83/1.
3. Check XENTRY: is error code Current, Stored, and not erasable?
- If yes, replace 48V on-board power battery G1/3 and set damage code 540HY73.
If no, short circuit must be somewhere other than the 48V battery. Possible causes: cables, screw connections, or 48V components.

To Troubleshoot:
- Disconnect each 48V components one at a time at 48V prefuse box.
- Check after disconnecting that component if the error code "B183319" is still in the 48V battery G1/3.
- If after disconnecting the fault goes from Current to Stored, or the vehicle can be started, then that current disconnected component is defective and should be replaced.
- If unable to reproduce or cannot clear faults open TIPS case.

Remedy 4:

Order and replace only 48V battery.

Remedy 5:

Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons
Road test and release vehicle if no further symptoms

If any abnormalities or this is a return visit after SW update was performed, open a TIPS case with the following:

Initial quick test
DCDC CUL
Time and date of occurrence
Perform the following checks

Perform below physical layer check for correct model inspections looking for corrosion, abnormalities, etc.

If nothing is found release to the customer.

Check the connection at W244/1 (Bus Bar)
Check for 48V terminal 40/41 connections with following instructions
Check each screw connection:
Can the cable lug be moved? Is it wobbling? Are deformations on the cable lug? Are there discolorations or signs of overheating visible? Are paint residues or dirt visible on the bolt or cable lug?
There are two types of ground bolts M6 and M8:
For M6 bolts with paint-scraping nut, the thread cuts into the paint and the current flows through the nut and the thread into the bolts. No further contact surface on the bolt is required!
If one of these is suspected of causing a contacting problem: create a TIPS case.
For M8 ground points, the current flows through the contact surface between the bolt foot and the cable lug. For these, ensure this surface is clean and not painted. If painted remove paint.

Model: 167

W106/1 (circuit 41 on battery)
F153/2 (Pre-fuse box engine compartment to DC/DC converter terminal 40)
F150/2 A2 (Pre-fuse box battery circuit 30)
W30/11

Model: 213, 238, 257, 290

F153/2 (Pre-fuse box engine compartment circuit 40)
Powerpack 48V (circuit 30 and 31)
W106/2 (battery grounds)
W106/3
N129 (ISA circuit 40 and 41)
W30/11

Last inspect 48V cables and control unit connectors for the following

Is the plug firmly locked?
Are the contact pins in the plug locked?
Are there signs of mechanical damage to the plug or pins (e.g. due to improper repair attempts, etc.)
Are there traces of water, corrosion or traces of thermal overload?
Check lines for damage such as abrasion, animal bites or other types of damage.
Check all 48V screw and plug connections on each component present in the vehicle:
Circuit 40/41 cables on components:
Document release torque of circuit 40/41 M8 bolts and retorque to 16N-m
Protect the cleaned ground points with spray against corrosion. Here is the parts number of the primer spray for protection: A0009863250 09

If after reviewing the above nothing is found the vehicle can be released to the customer.

If any abnormalities or this is a return visit, open a TIPS case with preliminary documentation requested.

Remedy 6:

Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons
Road test and release vehicle if no further symptoms

If fault P0606F1 is Active and Stored in the N127 PTCU and cannot be cleared, replace the 48V battery only, clear all faults, and road test.

If the CEL does not return, vehicle can be released.
If CEL returns or other symptoms are still present, open a TIPS case.

Remedy 7:

Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons
Road test and release vehicle if no further symptoms

Disclaimer

NOTE: The information contained in this document is intended for use by trained, professional technicians with the knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes resulting in the same or similar symptoms or conditions described in this document, and trained professional service technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained in this document does not guarantee warranty coverage nor does it extend the vehicle's warranty in any way.

SYMPTOMS

Overall vehicle > Power supply > Battery/On-board electrical system > Battery function > Battery discharges

Overall vehicle > Power supply > Battery/On-board electrical system > Battery/on-board electrical system display message > Battery/Alternator - Serviced Required

CONTROL UNIT/FAULT CODE

Control unit	Fault text
N83/1 - DC/DC converter (DDW) (DCDC48_222)	B183216 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has not been attained. B183301 - The battery for the 48V on-board electrical system has a malfunction. There is a general electrical fault. B183214 - The 48V on-board electrical system has a malfunction. There is a short circuit to ground or an open circuit. (LIB48_222) B183217 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has been exceeded. (LIB48_222) B183371 - The battery for the 48V on-board electrical system has a malfunction. The actuator is blocked. (LIB48_222) B183319 - The battery for the 48V on-board electrical system has a malfunction. The limit value for current has been exceeded. (LIB48_222)
N83/1 - DC/DC converter (DDW) (DCDC48_222)	B183301 - The battery for the 48V on-board electrical system has a malfunction. There is a general electrical fault. B183214 - The 48V on-board electrical system has a malfunction. There is a short circuit to ground or an open circuit. (LIB48_222) B183216 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has not been attained. (LIB48_222) B183217 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has been exceeded. (LIB48_222) B183371 - The battery for the 48V on-board electrical system has a malfunction. The actuator is blocked. (LIB48_222) B183319 - The battery for the 48V on-board electrical system has a malfunction. The limit value for current has been exceeded. (LIB48_222)
N83/1 - DC/DC converter (DDW) (DCDC48_222)	B183301 - The battery for the 48V on-board electrical system has a malfunction. There is a general electrical fault. B183214 - The 48V on-board electrical system has a malfunction. There is a short circuit to ground or an open circuit. (LIB48_222) B183216 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has not been attained. (LIB48_222) B183217 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has been exceeded. (LIB48_222) B183371 - The battery for the 48V on-board electrical system has a malfunction. The actuator is blocked. (LIB48_222) B183319 - The battery for the 48V on-board electrical system has a malfunction. The limit value for current has been exceeded. (LIB48_222)
N83/1 - DC/DC converter (DDW) (DCDC48_222)	B183301 - The battery for the 48V on-board electrical system has a malfunction. There is a general electrical fault. B183214 - The 48V on-board electrical system has a malfunction. There is a short circuit to ground or an open circuit. (LIB48_222) B183216 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has not been attained. (LIB48_222) B183217 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has been exceeded. (LIB48_222) B183371 - The battery for the 48V on-board electrical system has a malfunction. The actuator is blocked. (LIB48_222) B183319 - The battery for the 48V on-board electrical system has a malfunction. The limit value for current has been exceeded. (LIB48_222)
N83/1 - DC/DC converter (DDW) (DCDC48_222)	B183301 - The battery for the 48V on-board electrical system has a malfunction. There is a general electrical fault. B183214 - The 48V on-board electrical system has a malfunction. There is a short circuit to ground or an open circuit. (LIB48_222) B183216 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has not been attained. (LIB48_222) B183217 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has been exceeded. (LIB48_222) B183371 - The battery for the 48V on-board electrical system has a malfunction. The actuator is blocked. (LIB48_222) B183319 - The battery for the 48V on-board electrical system has a malfunction. The limit value for current has been exceeded. (LIB48_222)
N83/1 - DC/DC converter (DDW) (DCDC48_222)	B183301 - The battery for the 48V on-board electrical system has a malfunction. There is a general electrical fault. B183214 - The 48V on-board electrical system has a malfunction. There is a short circuit to ground or an open circuit. (LIB48_222) B183216 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has not been attained. (LIB48_222) B183217 - The 48V on-board electrical system has a malfunction. The limit value for electrical voltage has been exceeded. (LIB48_222) B183371 - The battery for the 48V on-board electrical system has a malfunction. The actuator is blocked. (LIB48_222) B183319 - The battery for the 48V on-board electrical system has a malfunction. The limit value for current has been exceeded. (LIB48_222)

OPERATION NUMBERS/DAMAGE CODES

Op. no.	Operation text	Time	Damage code	Note
			540HY73	Battery 48 V on-board electrical system - electrical fault
			5416D73	DC/DC converter 48 V on-board electrical system