Mercedes OBD/OBD2 Codes

Table of Contents

NOTE: 96 & later are OBD2 systems and require a scanner. For an OBD2 code list, please see our Mercedes-Benz code list or the appropriate generic list.

Mercedes: Accessing Diagnostic Trouble Codes

With Impulse Counter

  • With ignition switch On and shift lever in P/N position, connect impulse counter.
  • Depress Start button for at least two seconds but no more than four seconds, read codes.
  • Read codes until first code displayed appears again.
  • Codes will appear in ascending order.

With On-Off Ratio Readout

  • On models equipped with on board diagnostics, depress non-locking switch to convert control unit to read on-off readout ratio codes.
  • On all models, install on-off readout ratio tester to diagnostic socket.
  • Allow engine to idle and oil temperature to reach 140-176°F (60-80°C).
  • Read and record on-off readout ratio codes.

With Scan Tool

  • A hand-held tester can be connected to the underhood data link connector (DLC) X11/4 located at module box, or a generic scan tool can be connected to the generic connector X11/22 located in the tower edge of the instrument panel.
  • To access diagnostic trouble codes, follow the tool manufacturer’s instructions.

Mercedes: Clearing Diagnostic Trouble Codes

With Impulse Counter

  • Complete required repairs resulting from recorded codes.
  • With impulse code displayed, wait two seconds then depress Start button for at least six seconds.
  • Each code must be erased individually.
  • If no number is displayed, then diagnostic trouble codes are erased from memory.
  • If code higher than one appears, codes are still stored in memory.

With Scan Tool

To clear DTC’s, follow the scan tool manufacturer’s instructions.

Mercedes: Common OBD1 Diagnostic Trouble Codes

90-93 190E & 300 series (2.3L)
1No system malfunction.
2Throttle valve switch.
3Coolant temp sensor.
4Airflow sensor position indicator.
5Oxygen sensor.
6Not used.
7Td signal.
8Altitude correction capsule.
9Electro-hydraulic actuator (EHA).
10Throttle valve switch and/or Idle speed contact.
11Not used.
12EGR temp sensor.
91 & later 300 series (2.8L and 3.2L)
1No faults.
2Oxygen sensor inoperative.
3Lambda control inoperative.
4Air injection inoperative.
5EGR inoperative.
6Idle speed control inoperative.
7Ignition system failure.
8Coolant temp sensor-open or short circuit.
9Intake air temp sensor-open or short circuit.
10Voltage at Air Mass sensor too high or low.
11TN (RPM) signal defective.
12Oxygen sensor heater open or short circuit.
13Cam position sensor signal from-EZL/AKR ign. control unit defective.
14Intake manifold pressure at start too low.
15Full throttle Info defective.
16Idle speed info defective.
17CAN Data exchange-Malfunction between control units.
18Adjustable camshaft timing solenoid-open or short circuit.
19Fuel injectors-open or short circuit or Emission control system adaptation at limit.
20Speed signal missing.
21Purge switchover valve-open or shorted.
22cam position sensor signal defective.
23Intake manifold pressure w/ engine running too low.
24Starter ring gear segments defective.
25Knock sensors.
26Upshift delay switch over valve-open or shorted.
27Coolant temp sensor deviation between sensor ciruits 1 & 2.
28Coolant temp Sensor.
91-93 190E and 300 series (2.6L and 3.0L)
1No faults in system.
2Throttle valve switch(full throttle contact).
3Coolant temp sensor.
4Airflow sensor potentiometer.
5Oxygen sensor.
7TNA (RPM) signal.
8Altitude pressure signal from EZL Ignition control unit.
9Current to Electro-hydraulic actuator.
10Throttle valve switch(idle contact).
11Air injection system.
12Absolute pressure valves from ELZ ignition control unit.
13Intake air temp signal.
14Road speed signal at CIS-E control unit.
17Oxygen sensor signal.
18Current to idle speed air valve.
22Oxygen sensor heating current.
23Short to positive in regeneration switch over valve circuit.
25Short to positive in start valve circuit.
26Short to positive in shift point retard circuit.
27Data exchange fault between CIS-E control unit and EZL ignition control unit.
28Loose contact in coolant temp sensorcircuit.
29Difference in coolant temps between CIS-Eunit and EZL unit.
31Loose contact in intake air temp sensor circuit.
34Faulty coolant temp sensor signal from EZL unit.

Mercedes: Diagnostic Trouble Codes by Model / Year

ModelYearEngine identificationSystem
C220/280 (202)1994-006 cylinderBosch/Siemens
C230K/240/280 (202)1993-004/6 cylinderBosch ME 1.0/2.0/ ME-SFI 2.1
C·Ciass (202)20004 cylinderBosch ME 2.1
C-Ciass (203)2000-054 cylinderSiemens ME SIM4
C-Ciass (203)2006-086 cylinderBosch ME 2.7/2.7.1/9.7
C-Ciass (204)20086 cylinderBosch ME 2.7/2.7.1/9.7
CL (215)2000-048 cylinderBosch ME 2.0/2.8
CL (215)2005-0612 cylinderBosch ME 2.7/2.7.1/9.7
CL (216)2007-088/12 cylinderBosch ME 2.7/2.7.1/9.7
CL500/600 (140)1993-998/12 cylinderBosch ME 1.0/2.0/ ME-SFI 2.1
CLK (208)2000-036/8 cylinderBosch ME 2.0/2.8
CLK (209)20046/8 cylinderBosch ME 2.8
CLK (209)2006-086/8 cylinderBosch ME /2.7.1/2.8.1/9.7
CLK320 (208)1998-026 cylinderBosch ME 1.0/2.0/ ME-SFI 2.1
CLS (219)2005-088 cylinderBosch ME 2.7/2.8/9.7
E280/320 (124)1993-02/956 cylinderBosch/Siemens
E320 (210)1997-026 cylinderBosch ME 1.0/2.0/ ME-SFI 2.1
E-Ciass (210)2000-036/8 cylinderBosch ME 2.0/2.8
E-Ciass (211)2002-046/8 cylinderBosch ME 2.8
E-Ciass (211)2003-086 cylinderBosch ME 2.7/2.7.1/9.7
G-Ciass (463)2002-088 cylinderBosch ME 9.7
GL450 (164)2007-088 cylinderBosch ME 9.7
M-Ciass (163)2000-046/8 cylinderBosch ME 2.0/2.8
M-Ciass (164)2005-086/8 cylinderBosch ME 2.7/2.7.1/2.8/2.8.1/9.7
R-Ciass (251)2006-086/8 cylinderBosch ME 2.7.1/2.8.1/9.7
S320 (140)1994-996 cylinderBosch/Siemens
S320/420/500/6001993-996/8 cylinderBosch ME 1.0/2.0/ ME-SFI 2.1
S-Ciass (220)2000-048 cylinderBosch ME 2.0/2.8
S-Ciass (220)2005-068/12 cylinderBosch ME 2.7/2.7.1/2.8/2.8.1/9.7
S-Ciass (221)2007-086/8 cylinderBosch ME 2.7.1/2.8.1/9.7
SL (129)2000-026/8 cylinderBosch ME 2.0/2.8
SL (230)2002-048 cylinderBosch ME 2.8
SL (230)2005-086/8 cylinderBosch ME 2.7.1/2.8.1/9.7
SL320 (129)1993-976 cylinderBosch/Siemens
SL500/600 (129)1995-028/12 cylinderBosch ME 1.0/2.0/
SLK (170)2000-044/6 cylinderSiemens ME SIM4/ Bosch ME 2.8
SLK (171)2005-088 cylinderBosch ME 2.7/2.7.1/2.8/2.8.1/9.7
SLK 230 (170)1999-024 cylinderBosch ME 1.0/2.0/ ME-SFI 2.1
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3 years ago

I have a 2005 Mercedes 500 ML and where the odometer reading it is flashing a code of two wrenches then -1200 then -1300 and now -1400. Can you tell e what this means?

Kwaku baffoe
Kwaku baffoe
1 year ago

Hello friends my problem is this Mercedes ml 163 the jear didn’t write on the panel help me

Bob Turner
Bob Turner
4 years ago

Did you ever get a reply?

Alfredo arcilla
Alfredo arcilla
4 years ago

My car is 1988 Mercedes 560sl and diagnostic code is number 4.what would be the problem.