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‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
Starter only cranks when starter relay is jumped
I am starting a new thread for clarity. Recently, I encountered an issue with my car where it failed to start. The dashboard lights illuminate, followed by the appearance of the red battery light on the cluster after a few seconds. Notably, the starter and alternator are relatively new, with less than two years of use. What is peculiar is that when I jump the starter relay in the front fuse box the engine cranks but does not start. To verify fuel delivery, I removed the fuel hose from the fuel rail and used a jump wire in place of the starter relay. Observing fuel pouring out of the hose confirmed fuel supply to the engine. I am uncertain about what else to do. Could there be a bad ground connection? Anyone have the ground points for the starter, and alternator?
When attempting to start have you tried pressing down on the accelerator pedal? When my purge valve went bad the car would not start, but usually right after getting gas. I romped the accelerator pedal to the floor and it started.
Not saying your purge valve is the cause. Just something to try.
* I just read the post again and noticed the red battery warning.
Have you verified the battery is charged? Try using jumper cables/battery booster when trying to start? Put a charger on the battery.
Metal conducts electricity, unless it is heavily corroded. If starter or alternator have corrosion where they bolt on, remove, clean, and reattach.
The negative battery terminal will typically have a giant cable that attaches to the engine block and/or car frame.
Everything that is then bolted to the engine or metal car frame is grounded.
Get a voltmeter and place it in continuity mode and you can test this with greatest of ease.If there are 0 Ohms of resistance to alternator and starter from negative terminal then you have proven that ground isn’t the issue.
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
The fact that it cranks with the starter relay and getting fuel makes no sense. This video makes me think eis issue. though dashboard lights on. Next is the bcm? I get no codes when scanning the car
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
would the car crank with the starter relay jumped though if there was a ground issue ?
Originally Posted by MacVidMB-V8
Cars are made of metal.
Bolts are made of metal.
Metal conducts electricity, unless it is heavily corroded. If starter or alternator have corrosion where they bolt on, remove, clean, and reattach.
The negative battery terminal will typically have a giant cable that attaches to the engine block and/or car frame.
Everything that is then bolted to the engine or metal car frame is grounded.
Get a voltmeter and place it in continuity mode and you can test this with greatest of ease.If there are 0 Ohms of resistance to alternator and starter from negative terminal then you have proven that ground isn’t the issue.
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
To clarify, I apologize for the confusion. The fact that the vehicle fails to crank with the key in ignition position 2, yet cranks when a jump wire is used in place of the starter relay at the front sam, suggests what?
Among other things it pretty much guarantees that the starter and solenoid are good. So that is one direction you don’t need to aim the parts cannon.
But next we need to know WHICH terminals you are connecting at relay.
That relay probably only gets a 12V+ when the DAS has gone through all checks and sees that key and EIS and TCM and ECM and whatever else are ALL the right ones.
ie, there should be a 12V+ ready to connect to solenoid and another terminal that only goes 12V+ when DAS gives OK. When it gets the 12V+ it pulls the arm down connecting the solenoid to current. There will need to be a ground for the other side of the coil that pulls the arm down.
So with your multimeter, you can check which terminals are getting what current and when.
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
Pins 30 & 87.. what role would a multimeter play if I were to purchase one, given my unfamiliarity with its operation? Furthermore, the parts cannon comment seems irrelevant, considering the vehicle is approaching 20 years of age.
I recently used my multimeter when my fog light was not working and had a fault code short to ground/positive. The bulb was fine but installed a new one I had anyways. Still not working.
Used the multimeter to see what voltage I was getting at the plug. Less than 8v. So I connected directly to a ground point in the engine bay and voltage was fine. Then tested the ground wire from the plug to the ground point on the frame and sure enough it was bad. Ran a new ground wire and solved the problem. Never would have figured it out without a multimeter.
Cut and spliced in a new wire. Small butane torch for solder.
Test new ground wire for continuity to make sure the connector was fine- Good.
The setting just right of 200 at bottom is resistance with sound for continuity.
So you will get a numeric reading but beauty is you also get a “beep” sound. If you check the meter should be at 0.
So you don’t need to keep an eye on the number. First, touch probes together, you hear “beep” next you touch one to unpainted metal on car and point you want to test for ground, you should hear same beep.
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
Although I plan to try and diagnose the problem, I am not confident in my ability to do so effectively. Therefore, I will probably contact my mechanic and have him examine it further. Earlier today, I discussed the issue with him, and he believes it may be attributed to a corroded ground wire. As a final inquiry, is it possible that the N82/1 Battery control management module, which is still the original version, is preventing the vehicle from starting, considering the various updates listed on Mercedes Star?
‘16 Mercedes GLE450 amg,’15 Mercedes gla, coupe,’07 Mercedes w221,’12 Audi A
yes, I have a 40amp tender attached.
Originally Posted by TimC300
When attempting to start have you tried pressing down on the accelerator pedal? When my purge valve went bad the car would not start, but usually right after getting gas. I romped the accelerator pedal to the floor and it started.
Not saying your purge valve is the cause. Just something to try.
* I just read the post again and noticed the red battery warning.
Have you verified the battery is charged? Try using jumper cables/battery booster when trying to start? Put a charger on the battery.
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