Table of ContentsNOTE: 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) |
|---|
| 1 | No system malfunction. |
| 2 | Throttle valve switch. |
| 3 | Coolant temp sensor. |
| 4 | Airflow sensor position indicator. |
| 5 | Oxygen sensor. |
| 6 | Not used. |
| 7 | Td signal. |
| 8 | Altitude correction capsule. |
| 9 | Electro-hydraulic actuator (EHA). |
| 10 | Throttle valve switch and/or Idle speed contact. |
| 11 | Not used. |
| 12 | EGR temp sensor. |
| 91 & later 300 series (2.8L and 3.2L) |
|---|
| 1 | No faults. |
| 2 | Oxygen sensor inoperative. |
| 3 | Lambda control inoperative. |
| 4 | Air injection inoperative. |
| 5 | EGR inoperative. |
| 6 | Idle speed control inoperative. |
| 7 | Ignition system failure. |
| 8 | Coolant temp sensor-open or short circuit. |
| 9 | Intake air temp sensor-open or short circuit. |
| 10 | Voltage at Air Mass sensor too high or low. |
| 11 | TN (RPM) signal defective. |
| 12 | Oxygen sensor heater open or short circuit. |
| 13 | Cam position sensor signal from-EZL/AKR ign. control unit defective. |
| 14 | Intake manifold pressure at start too low. |
| 15 | Full throttle Info defective. |
| 16 | Idle speed info defective. |
| 17 | CAN Data exchange-Malfunction between control units. |
| 18 | Adjustable camshaft timing solenoid-open or short circuit. |
| 19 | Fuel injectors-open or short circuit or Emission control system adaptation
at limit. |
| 20 | Speed signal missing. |
| 21 | Purge switchover valve-open or shorted. |
| 22 | cam position sensor signal defective. |
| 23 | Intake manifold pressure w/ engine running too low. |
| 24 | Starter ring gear segments defective. |
| 25 | Knock sensors. |
| 26 | Upshift delay switch over valve-open or shorted. |
| 27 | Coolant temp sensor deviation between sensor ciruits 1 & 2. |
| 28 | Coolant temp Sensor. |
| 91-93 190E and 300 series (2.6L and 3.0L) |
|---|
| 1 | No faults in system. |
| 2 | Throttle valve switch(full throttle contact). |
| 3 | Coolant temp sensor. |
| 4 | Airflow sensor potentiometer. |
| 5 | Oxygen sensor. |
| 7 | TNA (RPM) signal. |
| 8 | Altitude pressure signal from EZL Ignition control unit. |
| 9 | Current to Electro-hydraulic actuator. |
| 10 | Throttle valve switch(idle contact). |
| 11 | Air injection system. |
| 12 | Absolute pressure valves from ELZ ignition control unit. |
| 13 | Intake air temp signal. |
| 14 | Road speed signal at CIS-E control unit. |
| 16 | EGR. |
| 17 | Oxygen sensor signal. |
| 18 | Current to idle speed air valve. |
| 22 | Oxygen sensor heating current. |
| 23 | Short to positive in regeneration switch over valve circuit. |
| 25 | Short to positive in start valve circuit. |
| 26 | Short to positive in shift point retard circuit. |
| 27 | Data exchange fault between CIS-E control unit and EZL ignition control
unit. |
| 28 | Loose contact in coolant temp sensorcircuit. |
| 29 | Difference in coolant temps between CIS-Eunit and EZL unit. |
| 31 | Loose contact in intake air temp sensor circuit. |
| 34 | Faulty coolant temp sensor signal from EZL unit. |
Mercedes: Diagnostic Trouble Codes by Model / Year
Hello friends my problem is this Mercedes ml 163 the jear didn’t write on the panel help me
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?
Did you ever get a reply?
My car is 1988 Mercedes 560sl and diagnostic code is number 4.what would be the problem.