When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Star cannot communicate to ESP ABC or ESM(electronic selector) modules.
With no comms to the 3 modules I had an idea that there was a problem causing all three to be down.
Things I've tried.
1. Replaced ESP module, no fix.( I have a spare ABC module too haven't installed it)
2. Disconnected each modules wiring one by one to see if one was causing the rest to not communicate.
3. Brake light switch
4. Rear sam(had water damage, lights weren't working before)
5. Tested K cable to contrul unit N15/5 ESM
With the K table test star tells you to test the resistance of X11/4 9 and 1.3 (n15.5)
I have no idea what 1.3 means.
Connector 1 pin 3? It's not clear. X11/4 9 means pin 9 I believe.
Anyways, I did test Pin 9 > pin 4(red cable with stripe) and I have 94 ohms on it.
I have no reading on pin 3, so pin 4 looks to be the correct one.
Star calls for less than an .6 ohm.
94ohms(assuming correct pins i diagnosed) means there is an open circuit.
Where do I go from here?
Can the Driver sam cause this?
I did buy one used on ebay but found out it has a lot of corrosion on it.
BTW the car runs and drives. If the ESM was dead, I don't believe the car would even start due to drive authorization
Normally when you have an issue affecting multiple control units or systems, the guided tests in Xentry are not worthwhile, but in this case it looks like you are on the right track and they actually got it spot on, but rather than blindly hooking up a meter and looking at the number, you still need to know/understand what you are testing. K-line is an early form of single wire network communication (which has been replaced by LIN, CAN, or Flex-Ray in modern cars). In this case, there is a dedicated k-line communication wire from X11/4 (obd port) to ESP/BAS (N47/5), ABC (N51/2), and ESM (N15/5). This wire is only used for diagnostic purposes (ie communication between the OBD port and these control units) so the vehicle should most likely be operating normally despite your issue. The test is correct as written. You already know you have a problem, so don't try to make your test results match the "known good" value. The k line wire goes from X11/4 pin 9 to connector X35/66 (driver's foot-well). From there it is split to three individual wires at Z6/33z2 (just a group of 4 wires crimped/soldered together, also in the driver's foot-well). These wires go to N47/5 pin 13, N51/2 pin 1, and N15/5 pin 3. If you have an open circuit to N15/5 pin 3, you have proved that your issue is in this k-line circuit (pin 4 is the kick-down signal, so it has nothing to do with this circuit). To be extra sure, you could also check continuity to the other 2 control units, but it's a pretty safe bet that the result will be the same. Your next step is to move to connector X35/66 and check continuity from there in each direction. Unless the connector itself is damaged or disconnected, you will find good continuity to either X11/4 or all 3 of the other control units, and high resistance/open circuit to the other end of the circuit. From there, trace the wire to find the damage. If you're lucky, the issue will be at/near X35/66 or the z-splice. If the issue is not between X11/4 and X35/66, you can assume that it's between X35/66 and the z-splice because any problem after the z-splice would only affect a single control unit.
Normally when you have an issue affecting multiple control units or systems, the guided tests in Xentry are not worthwhile, but in this case it looks like you are on the right track and they actually got it spot on, but rather than blindly hooking up a meter and looking at the number, you still need to know/understand what you are testing. K-line is an early form of single wire network communication (which has been replaced by LIN, CAN, or Flex-Ray in modern cars). In this case, there is a dedicated k-line communication wire from X11/4 (obd port) to ESP/BAS (N47/5), ABC (N51/2), and ESM (N15/5). This wire is only used for diagnostic purposes (ie communication between the OBD port and these control units) so the vehicle should most likely be operating normally despite your issue. The test is correct as written. You already know you have a problem, so don't try to make your test results match the "known good" value. The k line wire goes from X11/4 pin 9 to connector X35/66 (driver's foot-well). From there it is split to three individual wires at Z6/33z2 (just a group of 4 wires crimped/soldered together, also in the driver's foot-well). These wires go to N47/5 pin 13, N51/2 pin 1, and N15/5 pin 3. If you have an open circuit to N15/5 pin 3, you have proved that your issue is in this k-line circuit (pin 4 is the kick-down signal, so it has nothing to do with this circuit). To be extra sure, you could also check continuity to the other 2 control units, but it's a pretty safe bet that the result will be the same. Your next step is to move to connector X35/66 and check continuity from there in each direction. Unless the connector itself is damaged or disconnected, you will find good continuity to either X11/4 or all 3 of the other control units, and high resistance/open circuit to the other end of the circuit. From there, trace the wire to find the damage. If you're lucky, the issue will be at/near X35/66 or the z-splice. If the issue is not between X11/4 and X35/66, you can assume that it's between X35/66 and the z-splice because any problem after the z-splice would only affect a single control unit.
Thanks for the information, big help, greatly appreciated.
I have CAN B PDF for the benz that shows where a few connectors are, but do you have one on hand that pinpoints the location of the other ones you mentioned?
I will dig around online for them in the meantime, once I have the information I'll give everything a run down.
03-25-2019, 02:02 PM
