SFCabs

CLK 350 with M272

Car died while running and wouldn't restart afterwards.

I didn't initially have any codes, but did eventually get P0336 Tooth space on sensor rotor temporarily not detected or wire fault.

I replaced the Crankshaft position sensor and now there isn't any codes but the car still won't start. I popped up the rear seats and I'm not hearing the fuel pumps turn on when in position 2 or when cranking.

For the CPS sensor, I've read that you might need to Index the new sensor or do a sensor adaption?

My next steps are to check the gas (tank is full) and then check/replace the fuel pumps? Could a bad pump give the P0336 code?

insame1

a. did you use an OE cps?
b. check fuses and relays for the fuel before you go replacing everything.

SFCabs

Yup, I checked the fuel pump fuse and it was ok. I tried a new relay for the fuel pump too.

It's an OEM CPS.

If the fuel is bad, shouldn't I still hear the pump turning on?

Rudeney

Where did you buy the CPS? If Amazon or eBay, it might be a "fake".

SFCabs

I bought it at AutohausAZ or FCPEuro. It's the OEM part with the Mercedes logo scratched off. I'm thinking my CPS was actually ok and it's a pump problem.

insame1

yeah if you turn the key to po2 and cant here the pump prime fuel is the issue. Open the port on the end of the fuel rail and see if you have any pressure in there. If not I would test for power at the pump if no power then you need to trace that back. If you have power its probably the pump

xliemx717

this should help below. My car did the same think (CLK550) but had to get a new ECU due to processor gone bad. hence, would start when cold hear the fuel pump come on, but when hot nothing. Read this:

DTB
Date:
March 17, 2009
Order No.:
S-B-54.21/215a
Supersedes:
S-B-54.21/215 dated Feb. 11, 2009
Group:
54
Revision History
Revision
Date
Purpose
a
3/17/09
Technical Content Revised
-
2/11/09
Initial issue
SUBJECT:
All Models Equipped with Engine M272 and M273
Engine Cannot Be Started When Engine is Hot but Will Start After Engine has Cooled
If you receive customer reports in the above model vehicles that the engine cannot be started when the engine is hot but will start after the engine has cooled and there are no Diagnostic Trouble Codes stored in the ME control unit, check the signal that activates the fuel pump from the ME Control unit by monitoring pin 17 + and pin 4 on the small socket of N3/10 ME Control unit:
1. With the key in position 2 there should be 12 volts present across the pins, if not check the wiring from the ME control unit to the fuel pump relay or the fuel pump control module.
2. When cranking the engine, the 12 volts should go to 0 volts, if not it may be due to an open circuit in the ME control unit. In this case, replace the ME control unit and retest the signal to the fuel pump relay or the fuel pump control module. Refer to EPCnet for applicable part number. Note: A copy of the short test and all tests performed must accompany returned parts. If the documentation is missing or does not support the diagnosis, the warranty claim may be debited. Note: The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated on March 17, 2009. Please refer to Netstar �� Star TekInfo �� Star Time for the most current labor time allowance


My dealership confirmed and wanted to charge me $2540 for new ECU and reprogramming. I sent my old ECU to see if it could be rebuilt to Pressertech in Smyrna GA, got a remanufactured ECU with a stage 2 tune for half the cost with 2 year warranty. Car runs better plus has 417hp and 426tq.

Glyn M Ruck

Next time it cranks but won't start check the fuel pressure at the Schrader valve on the front fuel rail that links the injectors. s/b > 55psi while cranking. Sounds like intermittent fuel pump. Happens as rust particles stick to the magnets & ultimately seize the pump.