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My crank position sensor keeps going out. I have checked online, i have looked on the forums and videos etc and i can not find an answer.
Let me tell you my mods.
(Mods)
I have a 2007 SL55 motor my E55 is a 2003, Dual high flow AEM fuel pumps, Upgraded VRP fuel pump harness wiring bypassing the top hat, Star Motor werks looped fuel rail, 550cc injectors, Mid length headers, Euro charged tune, cat delete, X pipe, Bosch 010 pump, -10 Fan Mod, 77mm super charger pully, 168 Crank Pully, XL heat exchanger, belt wrap kit, 80mm throttle body. I think that is all. Not sure how much HP im making, probably 650+ or so
(Detailed explanation of the issue I have)
I have had this issue for a while and i will do my best to be as descriptive as possible without typing a 10,000 word essay and I will do recap.
I had owned the car for about 3 months so far. I first experienced the CPS going out when i was sitting in the car 100+ degree weather ( I live in California ) I had the A/C on at full blast and i was sitting there for about 20 minutes with the A/C on. i then left and i was at the stop light ( about 8 minutes from the time i left ) and the car just shut off on me. I would crank and would not start, i did this twice, i then pushed the car to the side and waited, i then just decided to crank it to see what would happen again and the car started right up. I thought everything was good until it shut off down the road about 10 minutes. and it continued to do that. At the time i didn't know what the issue was until another E55 owner on Instagram told me he was 95% sure that the CPS sensor was the issue. I changed it and sure enough it started right up and i had no issues. about 2 months later from driving off and on, it went out again. I was able to identify the issue right away and I changed it and I was good again. It continued to go out I have gone through at least 6-8 sensors, about 4-5 were OEM Bosch and the others were aftermarket import direct because I had no other choice at the time. I changed the sensors when the engine cools down, and I changed it with out even letting the car cool down, I changed it on the spot in about 10 minutes ( yes I burned my hands ) each time I changed it the car would work perfect right after It was changed.
Recap
-I had car for 3 months, CPS went out after sitting in 100+ degree heat with AC on.
-I had to replace CPS sensor every 2-3 months.
Has not been fixed.
Now let me explain other issues I have had and have. Just incase the info is needed.
(Issues)
1. I did have fuel issue, it was due to the tank fuel hose connected to the fuel pump being a little to large. The hose would pop off under pressure. I got the correct size, replaced it and that issue was fixed, never had a problem after that.
2. I had a miss fire. I had a check engine light so made it more simple. My secondary air pump was not working properly. I bought and replaced with a used one, works well. I also replaced the relay. Issue was fixed.
3. I had a issue with the fuel pump wiring. One day I lost power and car shut off and would not turn on, I thought it was the CPS sensor and I changed it and didn’t turn off, I checked fuel pressure and I had no pressure, so I checked the fuel tank ( just incase it was the hose). I noticed the top hat connection to the harness was brown and I looked and it was burned. Wiring harness was not affected. I purchased a upgraded fuel pump wiring kit from VRP speed. I bypassed the top hat connectors and connected the wires straight to the fuel pumps. Others have done this many times before on their cars. So I feel that it was fixed.
4. My speed cluster keeps going off and on. It resets randomly and the clock turns and does its thing. Light from the cluster shuts off and then on and stays on until it resets again. When that happens, the radio sometimes restarts and other times it stays on. Issue has NOT been fixed.
5. My rear left light has a bad connection, one of the light bulbs is not working and needs to be fixed. Not fixed yet.
I have only one heat exchanger and the Bosch 010 pump. Is it possible that I would need more cooling??? Secondary heat exchanger? Split cooling? Engine bay tank? Any ideas or thoughts would be appreciated.
My crank position sensor keeps going out. I have checked online, i have looked on the forums and videos etc and i can not find an answer.
Let me tell you my mods.
(Mods)
I have a 2007 SL55 motor my E55 is a 2003, Dual high flow AEM fuel pumps, Upgraded VRP fuel pump harness wiring bypassing the top hat, Star Motor werks looped fuel rail, 550cc injectors, Mid length headers, Euro charged tune, cat delete, X pipe, Bosch 010 pump, -10 Fan Mod, 77mm super charger pully, 168 Crank Pully, XL heat exchanger, belt wrap kit, 80mm throttle body. I think that is all. Not sure how much HP im making, probably 650+ or so
(Detailed explanation of the issue I have)
I have had this issue for a while and i will do my best to be as descriptive as possible without typing a 10,000 word essay and I will do recap.
I had owned the car for about 3 months so far. I first experienced the CPS going out when i was sitting in the car 100+ degree weather ( I live in California ) I had the A/C on at full blast and i was sitting there for about 20 minutes with the A/C on. i then left and i was at the stop light ( about 8 minutes from the time i left ) and the car just shut off on me. I would crank and would not start, i did this twice, i then pushed the car to the side and waited, i then just decided to crank it to see what would happen again and the car started right up. I thought everything was good until it shut off down the road about 10 minutes. and it continued to do that. At the time i didn't know what the issue was until another E55 owner on Instagram told me he was 95% sure that the CPS sensor was the issue. I changed it and sure enough it started right up and i had no issues. about 2 months later from driving off and on, it went out again. I was able to identify the issue right away and I changed it and I was good again. It continued to go out I have gone through at least 6-8 sensors, about 4-5 were OEM Bosch and the others were aftermarket import direct because I had no other choice at the time. I changed the sensors when the engine cools down, and I changed it with out even letting the car cool down, I changed it on the spot in about 10 minutes ( yes I burned my hands ) each time I changed it the car would work perfect right after It was changed.
Recap
-I had car for 3 months, CPS went out after sitting in 100+ degree heat with AC on.
-I had to replace CPS sensor every 2-3 months.
Has not been fixed.
Now let me explain other issues I have had and have. Just incase the info is needed.
(Issues)
1. I did have fuel issue, it was due to the tank fuel hose connected to the fuel pump being a little to large. The hose would pop off under pressure. I got the correct size, replaced it and that issue was fixed, never had a problem after that.
2. I had a miss fire. I had a check engine light so made it more simple. My secondary air pump was not working properly. I bought and replaced with a used one, works well. I also replaced the relay. Issue was fixed.
3. I had a issue with the fuel pump wiring. One day I lost power and car shut off and would not turn on, I thought it was the CPS sensor and I changed it and didn’t turn off, I checked fuel pressure and I had no pressure, so I checked the fuel tank ( just incase it was the hose). I noticed the top hat connection to the harness was brown and I looked and it was burned. Wiring harness was not affected. I purchased a upgraded fuel pump wiring kit from VRP speed. I bypassed the top hat connectors and connected the wires straight to the fuel pumps. Others have done this many times before on their cars. So I feel that it was fixed.
4. My speed cluster keeps going off and on. It resets randomly and the clock turns and does its thing. Light from the cluster shuts off and then on and stays on until it resets again. When that happens, the radio sometimes restarts and other times it stays on. Issue has NOT been fixed.
5. My rear left light has a bad connection, one of the light bulbs is not working and needs to be fixed. Not fixed yet.
I have only one heat exchanger and the Bosch 010 pump. Is it possible that I would need more cooling??? Secondary heat exchanger? Split cooling? Engine bay tank? Any ideas or thoughts would be appreciated.
Where are you sourcing the replacement crank sensors? If not from MB, then that should be your next step.
Where are you sourcing the replacement crank sensors? If not from MB, then that should be your next step.
From FCP Euro. And i will try that now that you mention it thank you. Someone on Facebook also recommended I check the relays to see if they are good just in case, so i will also do that.
Have you inspected the fuel pump relay? The OEM 40-amp relay is notorious for overheating and shutting the car down. After it cools, it may (or may not) function again.
Perform an advanced search on "E55 fuel pump relay and fuse maintenance" for more than you ever want to know about this issue. Since you have a 2003, this could very well be it. If it is, pull the fuel pump relay and the socket and replace with a 70-amp relay.
Have you inspected the fuel pump relay? The OEM 40-amp relay is notorious for overheating and shutting the car down. After it cools, it may (or may not) function again.
Perform an advanced search on "E55 fuel pump relay and fuse maintenance" for more than you ever want to know about this issue. Since you have a 2003, this could very well be it. If it is, pull the fuel pump relay and the socket and replace with a 70-amp relay.
I second this. I was having a similar issue and discovered the fuel pump relay melting. At first the relay would get hot and stop working. Then it cooled and worked fine. I also, thought it was Crank sensor and replaced it only to discover it was the fuel pump relay.
From FCP Euro. And i will try that now that you mention it thank you. Someone on Facebook also recommended I check the relays to see if they are good just in case, so i will also do that.
FCP should be selling MB source parts. May check with them to be sure. the MB part number is 003 153 28 28. It should be visible on the part. If not, then may not be from MB.
Have you inspected the fuel pump relay? The OEM 40-amp relay is notorious for overheating and shutting the car down. After it cools, it may (or may not) function again.
Perform an advanced search on "E55 fuel pump relay and fuse maintenance" for more than you ever want to know about this issue. Since you have a 2003, this could very well be it. If it is, pull the fuel pump relay and the socket and replace with a 70-amp relay.
I have not checked that out. I was reading up on it a little bit on the forums after i saw your reply. And some people are mentioning that they are having issues with their fuel especially people with aftermarket fuel pumps ( i have 2 AEM 320lph high flow pumps) So i will for sure check this out. What is odd to me though, the fact that i have changed the CPS sensor right after i had a stalling issue and "burnt cps sensor" issue, i change it and it runs perfect again. So that's why i mentioned its the CPS sensor and that it keeps going out.
Now check this out. Something i just noticed.
Just yesterday 06/07/2024 i was driving the car, hot day! over 100 degrees. Drove to the store, was on the freeway, driving back home, i forgot something and went back to the store right away, total driving was about 30 min. Before i was able to return home, my car stalled at the light. I waited a few seconds, turnkey and car struggled to turn on, but it turned on enough for me to be able to get out of the road and i kept going until the next stop light. The car shut off on me about 10 times LOL i did not want to pay $140 for a tow knowing that i can get the car home in pauses. A 15 min trip took me an hour!! to get the car home but i saved $140 by taking an hour to get home. Anyway. (Important) As the car stalled over and over, I noticed that when i press the break to slow down to a stop, the car stalled. If i was just at a light, the car stalled. if i was accelerating, the car was not stalling. I had never noticed this, reason being i would coincidently be close to home and it would stall once or twice and then i would change the sensor. Yesterday was the longest drive i have had and got it home. So, I feel that it can be fuel related somehow. What doesn't make sense to me, again, the CPS sensor would be changed and boom, it would be just fine. Maybe someone can explain the correlation.
FCP should be selling MB source parts. May check with them to be sure. the MB part number is 003 153 28 28. It should be visible on the part. If not, then may not be from MB.
Thats what i thought as well. Should be OEM but I will double check the part number to verify.
I second this. I was having a similar issue and discovered the fuel pump relay melting. At first the relay would get hot and stop working. Then it cooled and worked fine. I also, thought it was Crank sensor and replaced it only to discover it was the fuel pump relay.
Interesting. Do you happen to also have aftermarket fuel pumps? and was your E55 a 2003?
Just pull the trunk panel and look at the relay. If the relay is melted, the socket is melted, and the insulation is burned off the wires, you found the problem.
Taking the time to change the CPS gives the relay sufficient time to cool down and function again.
Been there, done that, got the T-shirt.
Takes 15-20 minutes to pull the trunk trim, pull floor panel, disconnect 12-volt socket, slip out the two illumination lights, remove plastic trim around hinges, and pull the panel. Your '03 should only have a 30-amp fuse and a single 40-amp relay over the passenger side rear wheel well. Your air pump relay is under the cabin air filter under hood rear passenger side. '04 and '05 are different and the '06 had yet another configuration.
The stock fuel pumps' amperage draw melts the stock relay. With your aftermarket pumps I am amazed it's still running...
Just pull the trunk panel and look at the relay. If the relay is melted, the socket is melted, and the insulation is burned off the wires, you found the problem.
Taking the time to change the CPS gives the relay sufficient time to cool down and function again.
Been there, done that, got the T-shirt.
Takes 15-20 minutes to pull the trunk trim, pull floor panel, disconnect 12-volt socket, slip out the two illumination lights, remove plastic trim around hinges, and pull the panel. Your '03 should only have a 30-amp fuse and a single 40-amp relay over the passenger side rear wheel well. Your air pump relay is under the cabin air filter under hood rear passenger side. '04 and '05 are different and the '06 had yet another configuration.
The stock fuel pumps' amperage draw melts the stock relay. With your aftermarket pumps I am amazed it's still running...
I really hope this is the case. I didnt have time yesterday to check and honestly I was avoiding looking at it late at night sonindont stay up stressing about it LOL. So I will check it out today. I will keep you all posted.
Just pull the trunk panel and look at the relay. If the relay is melted, the socket is melted, and the insulation is burned off the wires, you found the problem.
Taking the time to change the CPS gives the relay sufficient time to cool down and function again.
Been there, done that, got the T-shirt.
Takes 15-20 minutes to pull the trunk trim, pull floor panel, disconnect 12-volt socket, slip out the two illumination lights, remove plastic trim around hinges, and pull the panel. Your '03 should only have a 30-amp fuse and a single 40-amp relay over the passenger side rear wheel well. Your air pump relay is under the cabin air filter under hood rear passenger side. '04 and '05 are different and the '06 had yet another configuration.
The stock fuel pumps' amperage draw melts the stock relay. With your aftermarket pumps I am amazed it's still running...
Okay so I looked where you mentioned. But my E55 is one of the first models so different locations for the relays. I was able to find the users manual for the relay locations online. If I'm wrong anywhere, by all means let me know.
So my fuel pump fuse is in the spare wheel well, not on the passenger side like you mentioned. There is a relay there but from what in saw online, that is my air pump fuse, i sthill checked it, fuse was fine, connector was fine. So for the fuel pump fuse on mybE55 you can see it labeled on the manual as fuse box #2. located on spare tire area. So I started the car to make sure It would start, started up just fine. I then pulled the 30A fuse (where the manual says fuel pump 30A ) and the car would just crank but not start. So I did that to double check the connector, so that manual is correct.
One thing I noticed was on Fuse box #1 F4 also says Fuel pump and I have a 7.5 fuse and on the manual it says I should have a 15A, but the 7.5 was not burned. I will swap it but I just didnt have a lot of time today.
So now I feel like I'm back to square one -__- I have yet to try the OEM CPS from Mercedes, although I do have one right now on the car Bosch from FCP euro I have not swapped it out. My thought is that the car is just getting to hot and the CPS sensor is failing. During the winter the car ran longer with the CPS sensor, and summer just started and with a new sensor it lasted a week before it shut off on me, and i was just crusing.
"One thing I noticed was on Fuse box #1 F4 also says Fuel pump and I have a 7.5 fuse and on the manual it says I should have a 15A, but the 7.5 was not burned. I will swap it but I just didnt have a lot of time today."
That schematic is for the non-AMG E-class. On your AMG E-class, F4 and relay A in the Rear SAM are for the intercooler pump. In both AMG and non-AMG F4 is a 15-amp fuse and this remains the same no matter which harness variation.
Your air pump relay is located under the cabin air filter under hood.
The internet link you provided is inaccurate. I'm heading to church but will post additional info when I return home.
The harnesses are from start of production to 3/20/2003, 3/21/2003 to 8/31/2003, 9/1/2003 to 5/31/2005, and 6/1/2005 to end of E55 production.
I recommend you go ahead and replace the fuel pump relay. It's cheap to purchase and easy to replace once you get the trunk panel off.
Fuse lists from WIS follow. These cover the 2003 E55 with the original harness and the next iteration harness.
All rear prefuse lists indicate F82 is a 150 amp fuse feeding the harness over the passenger side wheel well. Early production just indicates connection to "Terminal 30 connection sleeve". I believe (based upon email conversation with an owner of one of the first E55s imported), this was the version where the 30-amp fuse was incorporated into the relay housing; I've not seen this one before or since. The 3/21/2003 to 8/31/2003 fuse list indicates connection to "Fuse box 2, right rear wheelhouse". This version has the fuel pump relay with a separate 30-amp fuse in a holder. Depending upon date of build, perhaps you have an early production model with the relay w/ fuse incorporated. If the original relay melted, the owner may have installed a standard relay, then pulled the 150-amp fuse and installed a 30-amp fuse. A feasible theory.
Hopefully the following copies are not too bad to read; the harness date is on the bottom of the copy.
"That schematic is for the non-AMG E-class. On your AMG E-class, F4 and relay A in the Rear SAM are for the intercooler pump. In both AMG and non-AMG F4 is a 15-amp fuse and this remains the same no matter which harness variation. Your air pump relay is located under the cabin air filter under hood. The internet link you provided is inaccurate. I'm heading to church but will post additional info when I return home. The harnesses are from start of production to 3/20/2003, 3/21/2003 to 8/31/2003, 9/1/2003 to 5/31/2005, and 6/1/2005 to end of E55 production."
Thank you i will take note of this.
Last edited by EliE55; 06-10-2024 at 12:00 PM.
Reason: forgot to add quote
I recommend you go ahead and replace the fuel pump relay. It's cheap to purchase and easy to replace once you get the trunk panel off.
Fuse lists from WIS follow. These cover the 2003 E55 with the original harness and the next iteration harness.
All rear prefuse lists indicate F82 is a 150 amp fuse feeding the harness over the passenger side wheel well. Early production just indicates connection to "Terminal 30 connection sleeve". I believe (based upon email conversation with an owner of one of the first E55s imported), this was the version where the 30-amp fuse was incorporated into the relay housing; I've not seen this one before or since. The 3/21/2003 to 8/31/2003 fuse list indicates connection to "Fuse box 2, right rear wheelhouse". This version has the fuel pump relay with a separate 30-amp fuse in a holder. Depending upon date of build, perhaps you have an early production model with the relay w/ fuse incorporated. If the original relay melted, the owner may have installed a standard relay, then pulled the 150-amp fuse and installed a 30-amp fuse. A feasible theory.
Hopefully the following copies are not too bad to read; the harness date is on the bottom of the copy.
Thank you for the schematics!!
And I checked my E55 is 03/21/2003. So Yes there is a 30A fuse in a fuse holder, and the relay i thought was for the air pump on the wheel well is probably the Relay for the fuel pump as you mentioned. I will try and get ahold of the previous owner and ask about the fuses to see if your theory is correct. The only question i have now is, why is the 30A fuse not burned? and why is the Relay connection not melted?? they both seem okay. So at this point im going to take pictures and post them in a collage of my fuse boxes and connectors. Im at work right now so i will get to it once i get home.
Fuel pump relay(s) for all W211 E55 models are located over the right rear wheel well. '05 has air pump relay and fuel pump relay over the right rear wheel well. '06 E55 has the air pump relay and two fuel pump relays over the right rear wheel well.
Fuel pump relay(s) for all W211 E55 models are located over the right rear wheel well. '05 has air pump relay and fuel pump relay over the right rear wheel well. '06 E55 has the air pump relay and two fuel pump relays over the right rear wheel well.
Awesome thank you!! So I remembered that mind doesn't have K27/1, K27/2 it only has one relay on the rear right wheel well location.
Last edited by EliE55; 06-10-2024 at 05:21 PM.
Reason: update informatioon
I was able to message and get ahold of the previous owner. He said he never changed any relay or fuse for the fuel pumps. Only thing that he changed was the injectors and the fuel pumps which i was already aware of. I will check relays and fuse again today but im still at work.
I will number them just in case they need to be used as reference for someone to point out.
FUSE BOX #1 rear right wheel well in trunk
FUSE BOX #2 rear spare tire well in trunk
Relay #1 Front right wheel well Relay under hood
Relay #2 right wheel well in trunk
So here are my fuse boxes and relays.
Relay number #1 is what that you guys are saying is for my Secondary air pump.
Relay #2 is fuel pump relay, correct?
Fuse box #2 is where my 30A fuel pump fuse is located correct?
Fuse box #1: Rear SAM
Fuse box #2: Rear Pre-fuse block
Relay #1: Air Pump Relay for the Secondary Air Injection
Relay #2: Fuel Pump Relay
You wrote earlier your car has a build date of 3/21/2003 which would be the first day of incorporated revisions. I'm going to go out sometime today and take a look at my pre-fuse box because it sure looks like yours incorporates the 30-amp fuse into the pre-fuse block. Photos like yours help me to fill in the various types of fuel pump electrical variations.
Fuse box #1: Rear SAM
Fuse box #2: Rear Pre-fuse block
Relay #1: Air Pump Relay for the Secondary Air Injection
Relay #2: Fuel Pump Relay
You wrote earlier your car has a build date of 3/21/2003 which would be the first day of incorporated revisions. I'm going to go out sometime today and take a look at my pre-fuse box because it sure looks like yours incorporates the 30-amp fuse into the pre-fuse block. Photos like yours help me to fill in the various types of fuel pump electrical variations.
As i wait for the sensor im just thinking and thinking about other possibilities and i thought of one other thing. Can low transmission oil be a cause of the transmission getting a little to hot and burn out the CPS?? My transmission oil was changed, its been a while but it was changed. What if they didn't put enough oil and maybe that little bit of oil that is missing is making the transmission to hot causing the sensor to fail?
OR
is it possible to have a a malfunctioning coolant temperature sensor? resulting in improper cooling of the engine, the cooling fans may not engage the fans at a proper time. I remember that my temp does fluctuate, although it doesnt overheat, it does go up and down, and from what i know, its always suppose to be at a steady temperature, on the temp reading it goes up one line and sometimes drops one line and then goes back up one line. And this happens under normal load, when crusing on the freeway or on the streets. Again its not overheating but the temp fluctuates, is the fluctuation normal?
Last edited by EliE55; 06-11-2024 at 07:33 PM.
Reason: updated info
Transmission has nothing to do with this. That would raise an entirely different basket of problems that usually result in limp mode. If key off then on and limp mode goes away, it is a mechanical/hydraulic issue with the transmission. If the limp mode does not go away after a key off/on, it is an electrical issue that can only be cleared by STAR/Xentry or equivalent. A bad conductor plate replaced with a good conductor plate will still leave the car in limp mode until the failure codes are cleared. Once cleared, the new conductor plate will function normally.
On both of my E55s (W210 analog gauge, W211 digital bar gauge), the coolant temperature will vary depending upon outside air temperature and engine load. Sometimes I look askance at the gauge but it always seems to have a hysteresis around the target temperature so all is good.
06-06-2024, 05:35 PM
