K6JRF at the mic K6JRF's Page
formerly W6FZC


My Mercedes Benz
S500 Coupe

K6JRF's MB S500 Cpe
(Updated: Jun 10, 2014)

Analyze and Troubleshoot "Check Engine" MIL and Electronic Control Units (ECU)!

Becker Radios

Becker Radio Repair
If you want to keep your Becker radio and Bose speaker system intact due to a failure in the radio or other major parts of the system, then consider replacing it with a combination radio/CD option. Or if you just want to upgrade your older radio to one of the newer models, check out Car Radio.de. They can supply a upgrade harness to make your older Mercedes compatible with the newer version radio/CD combos.

If your radio is 'clicking', 'popping' and has intermittant operation, then it probably needs repair. A good source here in San Diego, is The Radioman.    Call John at 619-298-6700 for details and directions to his shop.


Entering Radio Codes
After changing a battery or removing the radio's power connector, the radio will show "codes" on the display when powered up. Loss of power causes the radio to possibly 'think' that's it's being stolen! So to prevent car radio 'hijacking', the radio requires that you enter the five digit code that is unique to that radio.  Press the buttons for the five digits and then press "SC" to enter the codes into the radio.  If they are correct, the radio will play.  If you get a "wait", then either the codes were incorrect or the radio is dead.

Becker Connector Pins DIN-ISO pin out for 1994-1997 MB (Becker) Radios
Ever wondered what the pin out is for your Becker radio? I came across this information and thought it should be of interest to somebody at some time in the future. And that somebody could be me!

For more detailed information on the Becker Model 1492 radio ('94 - '96) for 'S' class cars, click the link for the repair, removal and operational info.

Pin 'A' 'B' 'C'
1 Speed dependent volume control Right rear + Connection
2 Not used Right rear - for Becker
3 Phone mute (ground to activate) Right front + CD changer
4 Constant 12V Right front -
5 Ant trig (12V when radio on) Left front +
6 Illumination Left front -
7 Ignition Left rear +
8 Ground Left rear -


Change from European to American Operation
Some of the Becker radios get set for operation in Europe. Thus it tunes in 9Khz increments instead of 10Khz and you cannot quite tune American radio AM stations because it tunes in like this: 756am. . .765am . . 774am, etc. Also the FM stations tune in 100Khz increments instead of the standard 200Khz. Thus 95.1. . .95.2. . . 95.3 instead of 95.1, 95.3, 95.5, etc.

The following procedure will get the radio tuned for American broadcast standards. Also it can set for European standards if you wish.

- Turn Ignition key to 'ON'
- Turn Becker radio 'ON'
- Press the 'TONE' button
- Immediately press the top two buttons (AM/FM and WB) simultaneously. 'TEST' will display
- Immediately press the 'SEEK' button. 'MODEL' will display
- Press the 'SEEK' button four (4) more times until 'FMAMR' displays.
- Press the 'TUNE' button until '200:10' appears. This means American standards: 200Khz FM and 10Khz AM spacing. Alternately, 100:9 means 100Khz FM and 9Khz AM spacing.
- Press and hold the 'SC' button until 'FMAMR' reappears
- Turn the radio off.

It has now been programmed to American radio standards.

Thanks to information from Horst Becker via Willy Mena


Description and Operation
The Becker two-piece radio has a self-diagnostic system. The system verifies data exchange via the BUS cable between the dash mounted radio control module (A2/4), CD changer (A2/6) and trunk mounted tuner/amplifier (A2/3). If a fault is detected, a DTC E1 thru E5 will appear on the radio display panel.

No procedure is required to access radio DTC's. The diagnostic chart below cross references DTC's - possible cause - remedy. If more than one remedy is listed, they are to be performed in the sequence listed.

Fault Table, DTC Readout, Radio Control Module (A2/4)
DTC Possible Cause Remedy
E1 EEprom in radio control module defective Replace radio control module (A2/4)
E2 Radio control module, CD changer and tuner/amp will not turn on due to open circuit or poor BUS connection



No voltage
Check BUS cable connections on radio control module (A2/4) and CD changer (A2/6)
Check for continuity between pins on BUS cables
Check condition of fuse on rear of CD changer and tuner/amp (A2/3)
Check for circuits 15, 30 and 31 at the radio control module, CD changer and tuner/amp
Replace tuner/amp (A2/3)
E3 Tuner/amp will not turn on due to open circuit or poor BUS connection between CD changer and tuner/amp


No voltage to tuner/amp (A2/3)
Check BUS cable connection on CD changer (A2/6) and tuner/amp (A2/3)
Check for continuity between pins of BUS cable from CD changer to tuner/amp
Check condition of fuse on rear of tuner/amp
Check for circuits 30 and 31 at tuner/amp
Replace tuner/amp (A2/3)
E4 Tuner/amp and/or CD changer will not turn ON. BUS communication OK
Replace tuner/amp (A2/3) and/or CD changer (A2/6)
E5 Tuner/amp will not turn ON. Bus communication OK Replace tuner/amp (A2/3)

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