M17x.xxx Check Engine Light on with Misfire DTC's
Topic number

LI07.61-P-070707

Version

4

Function group

07.61 ME fuel injection/ ignition system

Date

01-17-2020

Validity

M17x.xxx Engine Group

Reason for change

Read all steps

Reason for block

Complaint:

The customer complains of a check engine light (CEL) on. May also complain of the engine running roughly and/or a
loss of power.

Cause:

Multiple Causes

Remedy:

NOTE: Work through each step of the following. If at any point you must open a PTSS case reference step (8) for a
list of what must be included. Failure to include all attachments from step (8) will result in the case being sent back.
1.

Check that the ME Control Unit Software is Up to Date
•
Read out the injector performance data then update the ME SW
along with the VGS, PTCU, and FSCU control units (as available).
If ME update is not available STOP and proceed to step (2).
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Ensure that all ignition coils are part number A 177 906 42 02 or 177 906 95 00
Clear out the mixture adaptation data and perform 2 AMG Engine Adaptation Drives (this can be found in
the AMG User's Guide)
Read out the injector performance data, label this "IPDA" 5. Perfrom 2 more AMG engine adaptation drives
(do NOT clear the mixture adaptation data again), then read out and upload the injector performance data.
Label this "IPDB"
Perform a line graph version of the fault counter per the attachment: "Hot-Cold Misfire Detection"
Create a PTSS case and upload the old (showing the fault codes) IQT, the new (after ME update) IQT, IPDA, IPDB, and Fault Counter Readout
The data will be reviewed and you will be given instructions on
whether to release the vehicle or perform additional measures

2.

Smoke Test the Intake/Exhaust and Check for Leaks per the Attachment "Smoke Check"
•
Repair as necessary. NOTE: Smoke emanating from the wastegate arm bushing on the center section of
the turbo is normal when the turbo is cold.
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If no leaks are found, or repair of leak(s) does not remedy the complaint proceed to step (3).

3.

Perform a Compression Test (via PICO-Scope or Manually)
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If cylinders are not within 15% of each other in the compression test perform a leakdown test
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During the leakdown test, attempt to identify where the leakage is eminating from (head, valve(s),
block, ring(s)

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•

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Open a PTSS case and include your findings from step (2) Then proceed to step (4).
If cylinders are within 15% of each other, perform a leakdown test
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If leakage between cylinders is also within 15% proceed to step (4)
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If leakage between cylinder is not within 15%, attempt to identify where the leakage is eminating from
(head, valve(s), block, ring(s)
•
Open a PTSS case and include your findings from step (2) as well as previous steps. Then proceed
to step (4).

4.

Measure the Following Grounds.
•
If any reading is above 0.5 ohm, check the grounding locations of the model you're diagnosing (in the attachments).
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ME Connector F, Pin 1 to ground
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ME Connector F, Pin 2 to ground
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ME Connecter F, Pin 4 to ground
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ME Connector M, Pin 6 to ground
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Rework grounding locations by removing and cleaning the chassis ground point(s) regardless of ohm readings
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If rework/replacement does not remedy complaint, proceed to step (5)

5.

Inspect Ignition Coils and Verify they are PN: A 177 906 42 02 or 177 906 95 00
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Inspect the pins on the coil(s) of misfiring cylinder(s)
•
Inspect for physical damage on the coil(s) of misfiring cylinder(s)
•
If all coils are in good condition and PN A 177 906 42 02 or 177 906 95 00 swap the coil(s) of the misfiring
cylinder(s) with those of cylinder(s) that are not misfiring and road test the vehicle.
•
If the misfires move with the coils, replace the coils and the spark plugs on the original misfiring cylinder(s)
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Afterwards complete steps 1.3-1.7 and await further instruction
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If the misfires do not move with coils, or if the misfires do not reappear proceed to step (6)

6.

Boroscope the Tops of the Injectors and Look at Each Injector's IMA Code
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Ensure that the physical location of each injector matches what is coded in the ME
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If the injectors are not coded correctly, correct this in Xentry
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Afterwards complete steps 1.3-1.7 and await further instruction
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If injectors are coded correctly proceed to step (7)

7.

For Each Bank Perform a Xentry Guided High Pressure Fuel Test from Cold Start
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If the test fails for either bank, replace the high pressure fuel pump for that bank
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Afterwards complete steps 1.3-1.7 and await further instruction
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Include in your PTSS case the test results from the high pressure fuel test
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If the test passes for both banks, allow the vehicle to idle until operating temperature is achieved
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Shut the vehicle off and boroscope each cylinder, starting with the misfiring cylinder(s)
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Look for signs of a leaking injector
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If a leaking injector is found, upload pictures of it as well as all information gathered from steps 1-7 to
a PTSS case
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If no leaknig injector is found proceed to step (8)

8.

Test the Holding Pressure for Each Bank
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Allow the vehicle to idle until operating temperature is achieved
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Once operating temperature is reached, shut the vehicle down
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Monitor the fuel pressure on each bank at 15 minute intervals for 1 hour
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Record the fuel pressure reading for each bank at each 15 minute intervals

9.

Open a PTSS Case
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The following MUST be included in the case before it is sent:
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The original injector performance data from (step 1)
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Printouts of the SW level of the ME, VGS, and PTCU (step 1)
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The results of a compression test (PICO or manual (step 3)

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The results of a leakdown test (step 3)
Engine performance data (as a .pdf)
Line graph version of the fault counter from cold start (see attachment "Hot-Cold Misfire Detection)
The results of a high pressure fuel test from cold start for each bank (step 7)
The results of the fuel pressure hold test (step 8)

Attachments
File

Description

Hot-Cold Misfire Detection.pdf

Hot-Cold Misfire Detection

Smoke Check.pdf

Smoke Check

BR253_ground_points.pdf

253 Ground Points

C_Class Ground Points LS1.pdf

205 Ground Points

facelift 463 ground check.pdf

463 Ground Points

Ground points LS2_BR213_englx.pdf

213 Ground Points

GT Ground Check.pdf

190 Ground Points

Ground Points LS2_BR222 (002).pdf

222 Ground Points

Massestellen LS2_BR290_engl.pdf

290 Ground Points

Symptoms
Power generation / Engine management / Engine running / Runs rough/shakes
Power generation / Engine management / Indicator lamp / Engine diagnosis / lit
Power generation / Engine management / Engine performance / No/poor output

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