OldRockyTop

Hi everyone, I've been trying to wrestle a few issues to the ground recently and I'm coming back to a common theme.

I'm concerned my engine wiring harness is going bad. I'm new to the GL450 so I've not had much experience with this.

I have a code P0410 that keeps creeping back. Recently my car stalled three times while at moderate speed (40-55 mph). During those stalls, the car threw several codes at me including: P0393, P0340, P0102, P0607, P0101, P0343, P0348, P0368

These codes suggest that all of the camshaft sensors are having trouble and at the same time the MAF sensor is bad if I'm not mistaken.

All of these systems (MAF, Camshaft Sensors, and the Secondary Air Pump) feed through that same wiring harness.

To test my theory I pulled the power cable on the secondary air pump and tested the ground side. There was resistance between the pump ground connector and the ground on the car. I then moved the wiring harness during this measurement to witness the resistance change dramatically.

Has anyone else had these issues or something similar? I've had the car to the dealer who failed to diagnose the stall issue and incorrectly diagnosed the secondary air problem. Since they didn't say that the ECU is bad I'm hoping that it isn't the whole computer.

I would appreciate any thoughts you might have!

gl450x164

what year is your gl might neeed a new timing chain

007_e350

I think youre going down the right path, front Sam also had a notorious history of failures, signal actuator module, search it

OldRockyTop

It's an 07 GL 450, with about 95k on it. Is the timing chain a common issue I should consider? I honestly hadn't thought of that. Thanks for the heads up!

OldRockyTop

thanks so much for that thought 007_e350!

I'll research how to test that and report back soon!

ecmexchange

Sorry to hear you're having issues with your ride. If it turns out you do need work done on your ecu we offer a repair service that is well below dealer pricing. Let's hope it doesn't come to that though!

OldRockyTop

An update on my issue:

I removed the front SAM (located under passenger seat) and disassembled the module that might have been the culprit. No obvious damage to the unit and it does appear to be in good condition. No loose leads, so scorching, no water infiltration. (Photos attached)

If anyone has had issues with the SAM before, was the issue obvious? Or was the damage simply in the programming of the module and therefore can't be seen without SDS?

Is there a way to test this module without SDS (probably not)? I reinstalled the module after giving it a good canned air cleaning just in case in introduced any unwanted contaminants.

I think I'll pull the wiring harness just to see if there is anything obvious.

If there are any other thoughts I'm very open to listening. Thanks again!

Other recent work I did that may or may not be relevant:

1. Replaced Airmatic Compressor, filter, and input hose

2. Replaced Crankshaft Position Sensor (possible solution to stall issue)

007_e350

I lost the previous car due to Sam draining battery and dealership couldn't diagnose, months later I saw a tsb on this, they revised the unit ... the way to test my problem which may or maybot be relevant to yours, I hooked up an ammeter in series to the battery positive terminal and locked the car, let it sleep in 15 mins or so.. there should be no drainage from that point on .. my car would draw 3 amps every 30 mins... and battery would be done in 3 weeks ... I took fuses out repeated the rest etc but could not nail down the exact source and ended up trading the car, to my surprise one day another guy was getting Sam replaced due to tsb about it and it burnt my ********* to ashes

alx

Before you do any digging into the wiring remove cam sensors and look inside if the markings have moved. It certainly sounds like your timing (chain) is bad.

What resistance to ground are you observing? There might be some but it should be in the ohms range. Up to 60-100 is prolly ok.

OldRockyTop

Thanks 007_350 and ALX for your help with this. I'm still not sure that I've worked out all of the issues at this point.

However I did pull the top of the wiring harness apart this morning. I followed the ground wire of the Secondary air pump and voila, bad ground. That system is working perfectly now, and I'm posting a picture of the wiring harness ground location for anyone who might need to check that as part of an electrical issue. (I've marked it's location between the last and second to last ignition coils on the passenger side of the engine. Note the orange marker)

I'm not sure if that ground might have impacted the cam sensors, but I'll wait and see if those issues come back. They probably aren't related but a man can hope.

I'm sure the timing chain would be an undertaking that I'm not capable of, so do you know what I should plan to pay for such an operation?

Thanks again!

gl450x164

minimum 5k...ask me how i know

007_e350

Great find!!
One of the symptoms of extended timing chain is clattering sound on cold start, plenty of info on here, there's actually a fellow member that wrote up full diy with pics not too long ago, let me know if you can't find that post

OldRockyTop

gl450x164, that sounds awful, but somewhere in the ballpark I was expecting sadly.

Around what mileage did you do have to swap the chain?

gl450x164

i replaced mine at 166k it only affected the 07 mainly. it did start to show symptoms around 150k. it really varies by driver and maintenance though

dmiller00

Hello everyone. I have a 2009 GL 450 that keeps displaying a 'Malfunction' indicator with an arrow pointing underneath the vehicle. The back bounces as I ride down the street. It doesn't do this all the time. What could be the issue?

alx