W124 Diagnostic codes etc
 

Hey guys,

I was wondering what special equiptment you need to read the computer codes.

Also is there a website that has a list of codes and definitions? thanks

The codes are not the same for all W124.
If you let us know year and model, we can help.

It's a 1991 300e thanks!

Here they are
 

The first number is the code (#of flashes). Your car should be in one of the models below.

# Flashes PROBABLE CAUSE for Mercedes vehicles 190E and 300 series (2.3L) 1990 thru 1993
1 No System Malfunctio
2 Throttle Valve Switch
3 Coolant Temperature 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 Temperature Sensor

#Flashes PROBABLE CAUSE for Mercedes vehicles 300 series (2.8L and 3.2L) 1991 and later.
1 No fault in system
2 Oxygen sensor inoperative
3 Lambda Control inoperative
4 Air injection inoperative
5 Exhaust Gas Recirculation (EGR) inoperative
6 Idle Speed Control inoperative
7 Ignition System failure
8 Coolant Temperature Sensor - Open or short circuit
9 Intake Air Temperature Sensor - Open or shor 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 Camshaft Position Sensor signal from - EZL/AKR Ignition Control Unit defective
14 Intake manifold pressure at start too low
15 Fuel throttle information defective
16 Idle speed information defective
17 Controller Area Network (CAN) data exchange - malfunction between 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 shot circuit
22 Camshaft Position Sensor signal defective
23 Intake Manifold Pressure with engine running too low
24 Starter ring gear segments defective
25 Knock Sensor defective
26 Upshift Delay Switchover Valve - open or short circuit
27 Coolant Temperature Sensor deviation between circuit No. 1 and sensor circuit No. 2
28 Coolant Temperature Sensor (Coolant Temperature Change Monitor)

# Flashes PROBABLE CAUSE for Mercedes 190E & 300 series (2.6L & 3.0L) 1991 thru 1993
1 No faults in system
2 Throttle Valve Switch (full throttle contact)
3 Coolant Temperature Sensor
4 Airflow Sensor Potentiometer
5 Oxygen Sensor
6 Not Assigned
7 TNA (engine 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 EZL Ignition Control Unit
13 Intake Air Temperature signal
14 Road Speed signal at CIS-E Control Unit
15 Not assigned
16 Exhaust Gas Recirculation (EGR)
17 Oxygen Sensor signal
18 Current to Idle Speed Air Valve
19 Not Assigned
20 Not Assigned
21 Not Assigned
22 Oxygen Sensor heating current
23 Short circuit to positive in Regeneration Switchover valve circuit
24 Not Assigned
25 Short circuit to positive in Start Valve circuit
26 Short circuit 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 Temperature circuit
29 Difference in Coolant Temperatures between CIS-E Control Unit and EZL Ignition Control Unit
30 Not Assigned
31 Loose contact in Intake Air Temperature circuit
32 Not Assigned
33 Not Assigned
34 Faulty Coolant Temperature signal from EZL Ignition Control Unit

Hope this helps.

Pesuazo,
Could use these codes for my W124.021 M102.963 aswell.
I also understand there's some information about a DIY code reader. Can you please help/point me?

Thanks!

pesuazo,

I've been on this list for a few months now, but I seem to have missed most of the information on the fault codes.

Can you please give me some basic info on how I access thse codes?

I've got a '93 320 CE (UK model, if that makes any difference)

Look to the DIY article: Evaluating engine controls etc.

To get there click the DIY icon at the top of this page.

Hi,

The DIY article is great.

Suggest that you forget the DIY LED Fault Code Reader and go to Sears. Get their $30 Multimeter with Duty Cycle function.

It will do more for the money than the LED meter will -- especially with a 300E.

Get the CD manual as well. You are going nowhere quickly without it.

Good luck,

Two things I don't like about the LED is that it can be difficult to see in bright daylight, and it is also tedious to use for high pulse counts.

I'm going to attempt to build a pulse counter with digital display from about $10 worth of Radio Shack parts. If it is successful, I'm going to post a schematic with instructions on this site.

codes for 92 500E
 

Pesuazo,

Do you have the Fault code list for my 92 500E?
I had a 2, 6, and a 9 stored but after clearing I only have a 6. When I test for the codes the check engine light comes on and after clearing seems to stay out.

I am planning on O2 replacement as P/M but would like to know what the other faults are and what probable repairs are neededas i am having some wide open throttle issues.

Jeff

How can you read codes with a Multimeter? I thought all you can do with that is measure Lambda via duty cycle setting. I think the LED DIY tool is essential.

MR PESSUAZO
 

THANKS.

Please Mr Pesuazo, what are the codes and meanings for 300E and 190 E, 2,6L, 1988.?

Mario Farias

laprefar@cantv.net

Code Reader
 

For $35 I just bought a high quality hand made code reader off ebay and a .pdf of code descriptions was included: Mercedes Diagnostic Code Reader W124 300E and Others | eBay. Seems to work perfectly.

N.B.!

Models from 04/1986 (MY1987, US/Euro/AUS and all other, KE 3) have fault diagnosis via X11 (9-pin round diagnostic socket), by means on/off ratio, without faults memory.

The California-version models MY1988-89 also have fault diagnosis via X92 socket (8-pin test coupling with pushbutton and LED) by blink codes ("On-Board-Diagnose" system with faults memory).

And US-ver. (California + federal) models MY1990 (KE5 + MAS) has fault diagnosis via X11/4 socket (16-pin test coupling, for Cali-ver. with pushbutton and LED) by blink codes with memory.

+ also models with 2E-E carburettor (190 = 201.023, 200/200 T = 124.020/080) also have fault diagnosis via X11 by mean on/off ratio, without faults memory.


Ciao! :)

Will it read and delete codes? If not, the code reader is a must.

RayH