O2 sensors heater and turbo control valve circuits low...

[93blade]

Hi, help...
I have reduced power and multiple fault codes on a 2010 cl500 blue efficiency bi turbo v8.
I am assuming it is an electrical issue as too many components failing. I've checked fuses and some connectors and wastegate valve has 11 ohms resistance. Also coming up on dash is cooling fan fault. Not sure where to turn at moment. Some pointers would be good. I'll attach screenshot of faults..
Many thanks
Steve.

 

[ajlsl600]

How is battery. Or batteries? Use decent code reader note all above. Clear all see what comes back. Then Google the codes. Go from there.

 

[93blade]

How is battery. Or batteries? Use decent code reader note all above. Clear all see what comes back. Then Google the codes. Go from there.

Battery is good. Not that old.

 

[mattkh]

Also coming up on dash is cooling fan fault.

When did you last hear the cooling fan running..?

 

[ajlsl600]

Read codes. Don't own modern benz without decent code reader or deep pockets. Modern benz, n prob most others are DESIGNED to take money off you. ABOVE and some basic ability, interest is only way to mitigate this designed in feature.

 

[93blade]

When did you last hear the cooling fan running..?

Not sure.

 

[93blade]

Quick update, found fuse 23 20A blown. Blows as soon as I replace. Pulled relay c for terminal 87 engine and fuse doesn't blow. Disconnected turbo solenoid valve and evap control valve, also unplugged fan. Still blew. Just need to unplug o2 sensors and see what happens then. But they seem to be a pig to get at...

 

[93blade]

Checked everything now. Fuse 23 still blowing and has a short to earth on dead side of fuse. Unplugged o2 sensors but still no joy. Wiring all looks good as far as I can see..

 

[93blade]

Hi. I have a cl500 bi turbo 2010. It's blowing fuse 23. I've unplugged o2 sensors, turbo control valve and evap valve, also cooling fan, but fuse still blowing, wiring looks OK not sure where to go next.. Wiring diagram would be helpful...

 

[ajlsl600]

If blowing fuse and all attach components isolated(dissconected) u have a wiring to ground issue..

 

[93blade]

If blowing fuse and all attach components isolated(dissconected) u have a wiring to ground issue..

That's my thinking. But really struggling to locate at moment. Fault codes read all o2 sensor heaters low, turbo wastegate solenoid low and also have a cooling fan fault. Didn't know if this was on same supply.

 

[ajlsl600]

If one of them is blowing fuse. First test is all connected. New fuse , see which one blows fuse . Money on cooling fan. Or wres to, from. But check all.

 

[93blade]

Update... Fixed.... Sort of.
Fuse 23 feeds term 87 engine. Located this connector in plastic cable trunking underneath ecu unit. They are red with green stripe wires. Had to separate wires on this connector and test each one to earth. Found the culprit and tried to trace but seems to go down rear of engine under throttle body somewhere. Left disconnected and crimped the rest together. Replaced fuse and all held up. Cleared faults and engine and fan etc all back to normal with full power. Took for a test run then done another scan with a better scanner, thinking disconnected feed would throw up a fault for me, but no faults found and all is working...?
Has anyone got access to engine wiring diagram for M278 engine?

 

[93blade]

Update... Fixed.... Sort of.
Fuse 23 feeds term 87 engine. Located this connector in plastic cable trunking underneath ecu unit. They are red with green stripe wires. Had to separate wires on this connector and test each one to earth. Found the culprit and tried to trace but seems to go down rear of engine under throttle body somewhere. Left disconnected and crimped the rest together. Replaced fuse and all held up. Cleared faults and engine and fan etc all back to normal with full power. Took for a test run then done another scan with a better scanner, thinking disconnected feed would throw up a fault for me, but no faults found and all is working...?
Has anyone got access to engine wiring diagram for M278 engine?

 

[alexanderfoti]

What engine ecu connector number does it go to? If multiple wires crimped into one, you are describing a Z connector.

 

[93blade]

These wires are a positive feed to all the sensors around the engine, eg, o2 sensors and turbo waste gate solenoid. The returns from each go to the ecu.

 

[alexanderfoti]

What is first 6 digits of VIN

 

[AMGeed]

Best I can do is the fuse diagrams and layouts for the M278.

Fuse Box Diagram Mercedes-Benz CL-Class /S-Class 2006-2014

Fuse box diagram (location and assignment of electrical fuses and relays) for Mercedes-Benz CL-Class (CL550, CL600, CL63, CL65) / S-Class (S250, S280, S300, S320, S350, S400, S420, S450, S500, S550, S600, S63, S65) (C216/W221; 2006-2014).

fuse-box.info

A workshop manual including wiring diagrams can be downloaded for £9 95 from

Mercedes CL Class CL500 2006-2014 Workshop Repair Manual Download

Mercedes CL Class CL500 2006-2014 Workshop Manual used by Mercedes garages worldwide. Service & Repair, illustrations, Wiring Diagrams etc. Instant Download

workshopmanuals.org

 

[93blade]

What is first 6 digits of VIN

216373

 

[93blade]

Best I can do is the fuse diagrams and layouts for the M278.

Fuse Box Diagram Mercedes-Benz CL-Class /S-Class 2006-2014

Fuse box diagram (location and assignment of electrical fuses and relays) for Mercedes-Benz CL-Class (CL550, CL600, CL63, CL65) / S-Class (S250, S280, S300, S320, S350, S400, S420, S450, S500, S550, S600, S63, S65) (C216/W221; 2006-2014).

fuse-box.info

A workshop manual including wiring diagrams can be downloaded for £9 95 from

Mercedes CL Class CL500 2006-2014 Workshop Repair Manual Download

Mercedes CL Class CL500 2006-2014 Workshop Manual used by Mercedes garages worldwide. Service & Repair, illustrations, Wiring Diagrams etc. Instant Download

workshopmanuals.org

Perfect, thankyou..