AfterSales Diagnostic Sheet
MAS002203

From: Aftersales - TSO
To: Maserati Network
Modena, Italy | 20th May 2020

DMTL doesn’t work- Engine Warning Light (MIL,
Malfunction Indicator Light) ON on Cluster.
Issue: DMTL doesn’t work- Engine Warning Light (MIL, Malfunction Indicator Light) ON on
Cluster
Models: M157/M156/M161 Gasoline starting from MY17, DMTL-equipped..

Reference BOL:
-

-

BOL 1726561
BOL 1779716
BOL 1732942.

Issue description: Engine light switches ON on Cluster, neither effect nor symptoms affecting
the drivability.
Conditions: The Engine Warning Light may switch ON when running or at standstill.
Engine Temperature will not affect the symptom (warm or cold engine has no influence).
Engine ECU errors:
DTC in ECM module:
P043E P1405 P240C P240B -

EVAP System Leak Detection Reference Orifice Low Flow
EVAP System Leak Detection Pump Control plausibility check
EVAP System Leak Detection Pump Heater Control Circuit High
EVAP System Leak Detection Pump Heater Control Circuit Low

©2019 Maserati S.p.A.
Technical Service Operations
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P240A P2400 P2401 P2402 P2404 P2405 P2406 P2407 P0442 P0455 P0496 P0497 -

EVAP System Leak Detection Pump Heater Control Circuit/Open
EVAP System Leak Detection Pump Control Circuit/Open
EVAP System Leak Detection Pump Control Circuit Low
EVAP System Leak Detection Pump Control Circuit High
EVAP System Leak Detection Pump Sense Circuit Range/Performance
EVAP System Leak Detection Pump Sense Circuit Low
EVAP System Leak Detection Pump Sense Circuit High
EVAP System Leak Detection Pump Sense Circuit Intermittent/Erratic
EVAP System Leak Detected (small leak) => to find a leak in the EVAP system
EVAP System Leak Detected (large leak) => to find a leak in the evap system
EVAP System High Purge Flow – stuck open
EVAP System Low Purge Flow – stuck closed

Almost all the DMTL diagnosis run in Key position OFF, some others in Key position ON.

Troubleshooting:
1.

Try to get the information below from the Customer:
 Fuel refuelling habits: does the Customer overfills o trickle-fills
(Customer refuelling modulation can cause tank overfilling)?
 Possible Fuel Station Fuel pump issue (i.e. not delivering in a smooth
way) or irregular refuelling.
 Car washing habits: running engine during washing operations, highpressure jet used close to the DMTL area.
 Does the Customer use the Vehicle to trail a Boat or Trailer? In this
concern, check if the car is equipped with Tow Hook.

2.

Save first ECM scan report (Parameters + DTCs) through the MD/MD EVO tool
and attach it in BOL.

3.

If either or both the DTC P0496 or P0497, those related to a Purge valve
malfunction (Figure 4; Figure5), are not stored on ECM go to step 9.

4.

If either or both the DTC P0496 or P0497 are stored , regardless of whether other
DTCs at the same time, perform the following electrical checks on wiring harness:
 Check the Purge connector integrity (Figure 4; Figure5), make sure
there is no mark of oxidation and that pin tightness is secure and good.
 Check the fuse F39 integrity in FDU box and Purge valve wiring harness
integrity (Figure 3): absence of short circuits to Power Supply or Ground
and absence of open circuits. Perform these checks with KIN in OFF
position and disconnected battery power supply.

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Technical Service Operations
www.maserati.com

All rights reserved. Reproduction or translation
in whole or in part is not permitted without
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 Check at pin 1 (Figure 3) of the Purge Connector the power supply of
12V is present, with KIN in RUN position.
5.

Repair as necessary possible electrical issues.

6.

Perform, on ECM module, the Active Diagnosis “Canister purge valve 1” via
MD/MD EVO and check if the Purge valve is working properly, opening and
closing when modifying the duty cycle.

7.

If there still is mechanical issues at previous step proceed with Purge valve
replacement and again perform the Active Diagnosis “Canister purge valve 1” via
MD/MD EVO in order to check if the new Purge valve is working properly.

8.

Anyway:
 go to next step 9 in case, in the first ECM scan report, there were other
DMTL related DTC.
 go to step 20 in case, in the first ECM scan report, there were only
P0496 or P0497 .

9.

Erase all ECM DTCs using MD/MD EVO.

10.

Start the engine and wait for it to warm up.

11.

Perform ECM Procedure “DMTL tank leak detection” via MD/MD EVO and check
the presence of DTCs in ECM module at the end of such routine.

12.

Save a second ECM scan report (Parameters + DTCs) using MD/MD EVO and
attach it to BOL report. Perform the next steps even if no DMTL related DTC are
again stored on ECM module.

13.

Check the canister area and wheelhouse eventually notifying anomalies, crashes,
dirt or components not properly fitted, especially the rear wheelhouse guard on the
Canister side. Take pictures of the observed anomalies, if any.

14.

Verify that all the components of the Fuel vapour recirculation system are properly
fitted and well connected. These include connection pipes, DMTL, Canister, air
filter, tank, fuel filler neck (Figure 1, Figure 2) or possible leakage/ obstruction of all
system (a smoke test is advisable for this purpose). Take pictures of the observed
anomalies, if any.

15.

Check if DMTL or canister are contaminated by remarkable amount of water or
liquid fuel and eventually replace it.

16.

Perform the following electrical checks on wiring harness:
 Check the DMTL connector integrity, make sure there is no mark of
oxidation and that pin tightness is secure and good.
 Check the fuse F39 integrity in FDU box and wiring harness integrity

©2019 Maserati S.p.A.
Technical Service Operations
www.maserati.com

All rights reserved. Reproduction or translation
in whole or in part is not permitted without
authorization from Maserati S.p.A.

(Figure 3): absence of short circuits to Power Supply or Ground and
absence of open circuits. Perform these checks with KIN in OFF position
and disconnected battery power supply.
 Check at pin 4 (Figure 3) of the DMTL connector the power supply of 12V
is present, with KIN in RUN position.
17.

If there is issues at previous steps repair as necessary or proceed replacing
defected components and then go to step 19.

18.

If there is no issue at previous steps proceed with the replacement of the DMTL
pump:
 In order to avoid any kind of contamination, check and clean the canister
area during the component replacement.
 Check the integrity and cleanliness of the connection pipes from DTML
to Canister and eventually replace them. Make some pictures of the
possible anomalies.

19.

Quickly seal all the replaced components in order to avoid any external
contamination.

20.

Weigh the canister (excluding DMTL and pipes) and report the measured value on
BOL in grams. If the value exceed the threshold of fully saturated filter (2180
g/76.89 oz ) proceed even to replace the canister.

21.

Delete ECM DTCs with MD/MD EVO.

22.

Start the engine and warm it up.

23.

Perform ECM Procedure “DMTL tank leak detection” via MD/MD EVO and check
the presence of DTCs in ECM module at the end of such routine.

24.

Save a third ECM scan report (parameters + DTCs) and attach it to BOL.

25.

Seal and properly package all the replaced components to make them ready for
possible return request.

26.

Collect all the information and measurements requested and open a BOL as
Support Request type through the service Entry website.

©2019 Maserati S.p.A.
Technical Service Operations
www.maserati.com

All rights reserved. Reproduction or translation
in whole or in part is not permitted without
authorization from Maserati S.p.A.

Figure 1: Fuel vapour recirculation system on Sedan models.

Figure 2: Fuel vapour recirculation system on Levante.

©2019 Maserati S.p.A.
Technical Service Operations
www.maserati.com

All rights reserved. Reproduction or translation
in whole or in part is not permitted without
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Figure 3: - Connection diagram of the evaporative emissions control system.

Figure 4: - Canister Purge valve on Sedan Models.

Figure 5: - Canister Purge valve on Levante.

Aftersales - TSO
Gionathan Lunetta
©2019 Maserati S.p.A.
Technical Service Operations
www.maserati.com

All rights reserved. Reproduction or translation
in whole or in part is not permitted without
authorization from Maserati S.p.A.