X164 GL450 CDi starting issue

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New Member
Jun 9, 2011
My apologies if this has been discussed before or it’s not at the right column…admin can move it for me pls.

My 2010 GL450 CDI couple of months ago it started having an intermittent starting issue, in the morning it will start fine at first turn if the key and then during the day it will not start, when I jump start it, it will start right way even the engine turning will be fast you can tell the turn is also excited. Indie diagnose it and said it was battery. He did drop test on it and yes he said battery. I replaced the main battery and the auxiliary battery as they are all under the seat and same area. I replace the main battery with one from dealer and it was a Varta unit and the Aux was from a diy shop this one was a Yuasa unit, but same amps as the one that came out. After I replaced the batteries the car was starting fine all day everyday. After 2-3 weeks of car starting fine one day it started again same thing well not quite so it will start in the morning and during the day it will not start but it will crank but not firing up. If I put the battery jump pack on the battery, it will start fine and will go the rest of the day ok as normal. I have no fault light on dash at all no battery warning light or eml light at all.

When scanned the car came up with the following codes:

U010087 intelligence servo module (communications with the engine ecu has a malfunction - the message is missing

This code has always been there since i bought the car.

2043-002 check component B6/1 (camshaft hall sensor) signal faulty.

This code is new!!

What I am not understanding is: why is it when the car does not start i then put a jump pack on the car starts up right away?

If it was a fuel issue wouldn’t it be the same even if I put a booster on? This someone mentioned to me that could be the case but I l don’t know and doesn’t make sense
I think its more likely you have an injector leaking off rail pressure. These typically start to get worse when hot, causing hot start issues.

The newer battery/jump pack, is masking the issue by spining the engine (and the high pressure pump) faster.

Monitor rail pressure at cold and hot start to confirm.
I asked indie and he also said it seemed to be fuel issue, when It happened again, I plugged in a diagnostic to check fuel pressure and it was below 100 when trying to crank whist the cr didn't start, then when I put a booster pack on it fired up right away and this time the fuel pressure jumped from 91 to 125 then about 132 whilst running. so could this be an injector over fueling issue or high pressure pump?
You need to run a leak off test to determine if the issue is with the high pressure pump, or an injector leaking off rail pressure.

The refresh rate on these diagnostics may be too slow to monitor the rail pressure over a short time frame (1/2 seconds. Etc)

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