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1996 Mercedes E320
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11 Posts
Discussion Starter · #1 ·
The car stopped working after driving it to go shopping. It wouldn't crank nor start. We tried a new battery, starter, and K40 relay. The relay was actually used but I don't think that is the problem here. We used a test light to check for power on the starter and nothing shows. The K40 relay also isn't getting any power. What could be the issue here? Any help would be greatly appreciated.
 

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W210 Section Moderator
1998 E320 base sedan @ 235K miles
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10,569 Posts
Hello:) How did you know that the K40 is not getting power ? where did you look at ?

1) You ignition switch may be bad. When you turn to start it supplies 12V to pulse module.

2) The pulse module may not be closing the circuit to the starter.

3) you may have a bad starter lock-out switch Try shifting to Neutral to start then shift back to Park and try and so on.
 

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W210 Section Moderator
1998 E320 base sedan @ 235K miles
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10,569 Posts
OK.

Locate X22/1 in the diagram below.

Remove cover, and check the voltage on Pin 4 (where violet wire is connected) with respect to chassis ground. You should see no voltage with the key in position 2. Ask someone to turn the key to "start" and keep it there while you read the voltage on X22/1 pin 4. You should read 12V there as long as the key is in Start.
 

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1991 300D, 2001 E320, 2006 SLK280
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114 Posts
I had a similar problem months ago. Long story short, the blower for the computer modules seized causing a couple of fuses to blow on the K40 unit itself. Try disabling this cooling fan connector on the K40 unit( very small connector) and check those fuses. Replace fuses if necessary while leaving computer fan unplugged. Do a search on this issue and you should come up with a few leads
 

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W210 Section Moderator
1998 E320 base sedan @ 235K miles
Joined
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10,569 Posts
I had a similar problem months ago. Long story short, the blower for the computer modules seized causing a couple of fuses to blow on the K40 unit itself. Try disabling this cooling fan connector on the K40 unit( very small connector) and check those fuses. Replace fuses if necessary while leaving computer fan unplugged. Do a search on this issue and you should come up with a few leads
He has a 1996 E320 which has a different fusing, and starting arrangement. I do not think there is a computer fan.

For 1996 E320, the ignition key contact for start supplies battery voltage for the pulse relay which applies 12V to the starter, through the Starter lockout switch (NSS).

When the ignition is ON (run), Connector E pin 6 (red/blue cable) must have battery voltage and Connector E pin 4 must be hot all the time (red wire).
 

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Registered
1991 300D, 2001 E320, 2006 SLK280
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114 Posts
That makes sense. I was looking into this further and did indeed find the earlier W210 have a different system.


He has a 1996 E320 which has a different fusing, and starting arrangement. I do not think there is a computer fan.

For 1996 E320, the ignition key contact for start supplies battery voltage for the pulse relay which applies 12V to the starter, through the Starter lockout switch in the shifter (NSS).

When the ignition is ON (run), Connector E pin 6 (red/blue cable) must have battery voltage and Connector E pin 4 must be hot all the time (red wire).
 

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W210 Section Moderator
1998 E320 base sedan @ 235K miles
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10,569 Posts
Alright, then it is very likely that you have a bad Neutral Safety Switch (starter lockout switch) which is really mounted on the transmission for your car. Maybe it could be an adjustment issue, but if it has not been changed at all, it is very likely old, and tired.

Check the attached post out from MAVA.

http://www.benzworld.org/forums/8847529-post6.html
 

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W210 Section Moderator
1998 E320 base sedan @ 235K miles
Joined
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10,569 Posts
For cranking, if you look at the attached starting circuit for your car, the K40 relay is not involved. The starter lockout/back up lamp switch (that you replaced) switches the 12V on violet wire to the violet/white wire when the gear is in either Park or Neutral and when you turn the ignition key to Start..

You said you had measured the voltage at the violet wire at X22-1 connector and there was power when the ignition was in start position.

You can test the voltage after the NSS (violet/white wire) while ignition is in Start. If no 12V, the means the switch is not in Park or Neutral.
 

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