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Hello all,
for the past year i had an intermittent ghost issue with my ECT sensor, as it sometimes fluctuate irregularly, from constantly sitting still at 85 degress and then suddenly drops to 30 and back again to 85 and sometimes it disconnects entirely and then reconnect, the weird thing is at the same time the ambient temperature sensor starts acting up as well, from having a 25 degrees reading to suddenly giving 65 degrees, both of the temperature sensors act up at the same time and there is no pattern, sometimes it appears as soon as i start the car and sometimes after driving for a while, and sometimes with the engine off and ignition on, it just fluctuate around, honestly it's really frustrating and weird, i checked the wiring of the ect no apparent damage, i checked the resistivity of the wires and i had a 0.8 ohm reading which i think is good, i replaced the sensor but still the issue exits,
i am unable unable to pinpoint the exact reason for the issue, if it was an ECU issue it should have affected the other sensors as well since they all have the 5v reference voltage, i checked the wiring diagram for both sensors, it appears that the ECT is connected to the ECM directly while the ambient temperature sensor is connected to the front sam unit, my theory is that the ambient temperature sensor might be faulty and affecting the reference voltage of the ECT sensor,
any advices regarding this matter or if someone encountered a similar issue?
Hello all,
for the past year i had an intermittent ghost issue with my ECT sensor, as it sometimes fluctuate irregularly, from constantly sitting still at 85 degress and then suddenly drops to 30 and back again to 85 and sometimes it disconnects entirely and then reconnect, the weird thing is at the same time the ambient temperature sensor starts acting up as well, from having a 25 degrees reading to suddenly giving 65 degrees, both of the temperature sensors act up at the same time and there is no pattern, sometimes it appears as soon as i start the car and sometimes after driving for a while, and sometimes with the engine off and ignition on, it just fluctuate around, honestly it's really frustrating and weird, i checked the wiring of the ect no apparent damage, i checked the resistivity of the wires and i had a 0.8 ohm reading which i think is good, i replaced the sensor but still the issue exits,
i am unable unable to pinpoint the exact reason for the issue, if it was an ECU issue it should have affected the other sensors as well since they all have the 5v reference voltage, i checked the wiring diagram for both sensors, it appears that the ECT is connected to the ECM directly while the ambient temperature sensor is connected to the front sam unit, my theory is that the ambient temperature sensor might be faulty and affecting the reference voltage of the ECT sensor,
any advices regarding this matter or if someone encountered a similar issue?
Internally broken wire? Loose connection/pin? Intermittent connection due to motion? Perhaps checking around the connectors
03. I assume you are "reading" ECT and AAT data from your instrument cluster...yes ?
Get a scanner or an OBD2 gauge and remove the Instrument Cluster from the equation. You see, Instrument Cluster is a processed data and a 2nd hand data from ECM or Front SAM.
Just in case you Ins-Cluster is the bad dude.
If you use a scanner, the ECT and AAT data is more direct from ECM for ECT and Front-SAM for AAT
Now do the wire wiggle test at sensor body, full length wire harness and the ECM & Front SAM connector and see what happen.
Is your M271 the EVO one as in M271.8 ?
I have with me M271.8 EVO ECM wiring , but on a C200 W204. It should be the same for W212 if the engine is the same.
At ECM if a pin ID is 31, that is Ground, but since this is not the common W ground. This is "clean" ground the Z7/43.
The ECM W common ground is W16/5 OR W16/6 depending if Left Hand Drive or RHD. Again I am using C200 W204 as reference for the engine bay side grounding. But you will understand the logic if on W212 and I am sure you have complete wiring diag.
I spent time on this M271.8 EVO for a friend. Misfire, whacky one, intermittent.
The ECM was the bad dude and one of the female connector at the ECM big connector was also bad contact for Ignition 1 trigger.
Well, the ECM connector was remove/re-connected so many times during the test, no surprise the high amperage baby sized 1.2mm MLK of Ignition 1 female connector at the ECM connector goes "tired",
afterall this is a 20-50 insertion cycle class male and female connector in use. This engine is still using the dummy COP coil which its driver is at the ECM and not at the COP itself.
So all 4 baby sized 1.2mm MLK male & female connector of Ignition triggers at ECM body and ECM connector carries 10 AMPS per firing. Stupid design, because the connector at the COP itself is the robust 2.8mm one, I believe SLK 2.8
The female connector usually is the one that goes bad first always, because it has the "springy-ness" function which weakens after too many insertion cycle.
OK...good luck with the wiggle test and using scanner/OBD2 gauge.
Last edited by S-Prihadi; 10-27-2022 at 12:43 AM.
Reason: typo correction
03. I assume you are "reading" ECT and AAT data from your instrument cluster...yes ?
Get a scanner or an OBD2 gauge and remove the Instrument Cluster from the equation. You see, Instrument Cluster is a processed data and a 2nd hand data from ECM or Front SAM.
Just in case you Ins-Cluster is the bad dude.
If you use a scanner, the ECT and AAT data is more direct from ECM for ECT and Front-SAM for AAT
Now do the wire wiggle test at sensor body, full length wire harness and the ECM & Front SAM connector and see what happen.
Is your M271 the EVO one as in M271.8 ?
I have with me M271.8 EVO ECM wiring , but on a C200 W204. It should be the same for W212 if the engine is the same.
At ECM if a pin ID is 31, that is Ground, but since this is not the common W ground. This is "clean" ground the Z7/43.
The ECM W common ground is W16/5 OR W16/6 depending if Left Hand Drive or RHD. Again I am using C200 W204 as reference for the engine bay side grounding. But you will understand the logic if on W212 and I am sure you have complete wiring diag.
I spent time on this M271.8 EVO for a friend. Misfire, whacky one, intermittent.
The ECM was the bad dude and one of the female connector at the ECM big connector was also bad contact for Ignition 1 trigger.
Well, the ECM connector was remove/re-connected so many times during the test, no surprise the high amperage baby sized 1.2mm MLK of Ignition 1 female connector at the ECM connector goes "tired",
afterall this is a 20-50 insertion cycle class male and female connector in use. This engine is still using the dummy COP coil which its driver is at the ECM and not at the COP itself.
So all 4 baby sized 1.2mm MLK male & female connector of Ignition triggers at ECM body and ECM connector carries 10 AMPS per firing. Stupid design, because the connector at the COP itself is the robust 2.8mm one, I believe SLK 2.8
The female connector usually is the one that goes bad first always, because it has the "springy-ness" function which weakens after too many insertion cycle.
OK...good luck with the wiggle test and using scanner/OBD2 gauge.
i replaced the ECT, actually i confirmed the readings using an OBD scan tool, the sensors are in fact giving the same readings as the instrument cluster, i wanted to avoid stripping down the wires from the PE insulation as those are hard to come by where am from but it looks like the problem might possibly lie within a faulty ground cable, I'll check the wiring diagrams, strip down the cables and test them properly and I'll let you all know what i found.
03. I assume you are "reading" ECT and AAT data from your instrument cluster...yes ?
Get a scanner or an OBD2 gauge and remove the Instrument Cluster from the equation. You see, Instrument Cluster is a processed data and a 2nd hand data from ECM or Front SAM.
Just in case you Ins-Cluster is the bad dude.
If you use a scanner, the ECT and AAT data is more direct from ECM for ECT and Front-SAM for AAT
Now do the wire wiggle test at sensor body, full length wire harness and the ECM & Front SAM connector and see what happen.
Is your M271 the EVO one as in M271.8 ?
I have with me M271.8 EVO ECM wiring , but on a C200 W204. It should be the same for W212 if the engine is the same.
At ECM if a pin ID is 31, that is Ground, but since this is not the common W ground. This is "clean" ground the Z7/43.
The ECM W common ground is W16/5 OR W16/6 depending if Left Hand Drive or RHD. Again I am using C200 W204 as reference for the engine bay side grounding. But you will understand the logic if on W212 and I am sure you have complete wiring diag.
I spent time on this M271.8 EVO for a friend. Misfire, whacky one, intermittent.
The ECM was the bad dude and one of the female connector at the ECM big connector was also bad contact for Ignition 1 trigger.
Well, the ECM connector was remove/re-connected so many times during the test, no surprise the high amperage baby sized 1.2mm MLK of Ignition 1 female connector at the ECM connector goes "tired",
afterall this is a 20-50 insertion cycle class male and female connector in use. This engine is still using the dummy COP coil which its driver is at the ECM and not at the COP itself.
So all 4 baby sized 1.2mm MLK male & female connector of Ignition triggers at ECM body and ECM connector carries 10 AMPS per firing. Stupid design, because the connector at the COP itself is the robust 2.8mm one, I believe SLK 2.8
The female connector usually is the one that goes bad first always, because it has the "springy-ness" function which weakens after too many insertion cycle.
OK...good luck with the wiggle test and using scanner/OBD2 gauge.
later I'll retrieve the location for all ECM W common ground locations and check them one by one, i'm starting to believe it is infact a grounding issue according to the diagram the Z7/43 connector sleeve supply ground to the ECT, CPS and the intake air temperature sensor, from time to time the ecm actually throws some CPS voltage errors, the issue might lie within a faulty ground from the W common Grounds, or the Z7/43 Connector sleeve, or even the wire supplying ground from the ECM pin 33 to the connector sleeve Z7/43, but i am more inclined to an issue within the W common ground because the AAT sensor is connected to front sam not the ECM so it has to be a specific W ground point supplying both the ECM and the Front sam and accordingly affecting both AAT and ECT grounds. By the way did have luck finding the AC water drain points on the w212, I'm truly curious about their condition since i don't see any water dripping from the vehicle.
The HVAC drain hoses, 2 of them and above the tranny tunnel
If you want to get more water out from HVAC system do a sudden braking, even at low speed and more water will ooze out.
Or jump accelerate or use brake torque to dance the car rear suspension, more water from HVAC will ooze out.
This is the LEFT side one, in green. The two hoses are not of equal height, do note.
LEFT SIDE ONE
RIGHT SIDE ONE, higher
ADD, close up view
SOURCE OF THE HOSES AT HVAC ASSY- Suposedly from W212 E350
The hoses, this is from E550 W212. See one is taller.
Well, my W212 ground if for engine bay and the MAIN ONE for engine starter/block, I cleaned them all already and they are beefed up too and also for ECM
The trunk one also done, cleaned and tigtened and marked. Any red line marker on my car bolt/stud/nut, that is my doing.
Interior ones I have not done anything to it. Cali have done a lot of his interior ground points.
The follow up of the grounding thingys is ..........
For alternator superb charging algo, solution is KILL the LIN connection to it and let alternator work its own magic using its own charge controller and not by stupid ECM charging algo.
***Sensors/component direct from Engine Computer**
Connector M ( engine side ) pin 33 >> Z7/43
Z7/43 >> B17/8 Charge air temperature sensor ( intake air after aftercooler )
Z7/43 >> B11/4 Coolant temperature sensor
Z7/43 >> B70 Crankshaft hall sensor ( the other pin from Z27/41 connection )
Connector M ( engine side ) pin 68 >> Z7/41
Z7/41 >> B70 Crankshaft hall sensor ( the other pin uses Z27/43 connection )
Z7/41 >> M59 Intake manifold swirl flap actuator motor ( 1 other pin from Z7/43 )
Z7/41 >> B28/15 Pressure sensor upstream of compressor impeller
Z7/41 >> B4/6 Rail pressure sensor ( HP fuel pump rail )
Z7/41 >> B28/7 Pressure sensor downstream of throttle valve ( 1 other pin from Z7/44 )
Z7/41 >> B28/6 Pressure sensor upstream of throttle valve ( 1 other pin from Z7/44 )
Connector M ( engine side ) pin 53 >> Z6/8
Z6/8 >> B6/15 intake camshaft hall sensor
Z6/8 >> B6/16 B6/16 exhaust camshaft hall sensor ( 1 other pin from Z7/36z2 fuse 22 )
I hope the Z7/43 splice is not at the part where the engine wire harness is rubber molded.
I was looking for the capacitor and I could not find it, it is inside the freakin' rubber moulding of wire harness
Hello all,
first of i’d like to thank all of you for participating in this thread, and sorry i took so long to respond I’ve been dealing with this intermittent issue and i still i am, but i think i got to the bottom of it,
i’ve tested all the wires for the ECT and ambient Temperature sensor and the ECM ground wires, as well as every ground wire available in the wiring the diagram, checked all sensor connectors for signs of oil, I’ve even went as far as replacing the ecm and sensors but still haven’t solved this issue.
the only thing I’ve noticed is upon wiggling the female connector for the ecm, it causes the issue to disappear for a couple of weeks, i am starting to think that the issue lies within the ECM’s female connector. I will have this female connector replaced and re-pinned. As i think it is the culprit.
upon completion of replacement I’ll let you all know what happened.
Well, I did mention similar problem I had, back then...........post #4
I spent time on this M271.8 EVO for a friend. Misfire, whacky one, intermittent.
The ECM was the bad dude and one of the female connector at the ECM big connector was also bad contact for Ignition 1 trigger.
Well, the ECM connector was remove/re-connected so many times during the test, no surprise the high amperage baby sized 1.2mm MLK of Ignition 1 female connector at the ECM connector goes "tired",
afterall this is a 20-50 insertion cycle class male and female connector in use. This engine is still using the dummy COP coil which its driver is at the ECM and not at the COP itself.
So all 4 baby sized 1.2mm MLK male & female connector of Ignition triggers at ECM body and ECM connector carries 10 AMPS per firing. Stupid design, because the connector at the COP itself is the robust 2.8mm one, I believe SLK 2.8
The female connector usually is the one that goes bad first always, because it has the "springy-ness" function which weakens after too many insertion cycle.
Well, I did mention similar problem I had, back then...........post #4
I spent time on this M271.8 EVO for a friend. Misfire, whacky one, intermittent.
The ECM was the bad dude and one of the female connector at the ECM big connector was also bad contact for Ignition 1 trigger.
Well, the ECM connector was remove/re-connected so many times during the test, no surprise the high amperage baby sized 1.2mm MLK of Ignition 1 female connector at the ECM connector goes "tired",
afterall this is a 20-50 insertion cycle class male and female connector in use. This engine is still using the dummy COP coil which its driver is at the ECM and not at the COP itself.
So all 4 baby sized 1.2mm MLK male & female connector of Ignition triggers at ECM body and ECM connector carries 10 AMPS per firing. Stupid design, because the connector at the COP itself is the robust 2.8mm one, I believe SLK 2.8
The female connector usually is the one that goes bad first always, because it has the "springy-ness" function which weakens after too many insertion cycle.
Yes, I’ve seen the post, if not for you I wouldn’t have even considered it (i never would have thought that these male female connectors might have an insertion cycle you’re a genius and a life saver i truly appreciate your assistance) , i went and searched for your thread, to figure out how to re-virginize (in love with the term😂 the female connector.
Last edited by Wail maghazi; 03-18-2023 at 10:11 AM.
For 02 a loaded 3 amps test would be good enough for 0.5mm cable and 1 to 1.5mm cable you test 5 amps and bigger cable 2.5mm one you test at 10 amps. Each test 30 seconds is good enough.
While doing so, "massage" and shake the cable. This is lots of work as you need male terminals suitable for the other end of the cable too and accessing them.
Becareful when doing 02, as this is injecting power be it +12V or -12V, so all sensor/devices at the other end of the cable has to be disconnected and car battery disconnected too, surely ECM has to be disconnected too.
Example what I bought and I am not done yet actually.
I basically tried to buy many types as I do note exactly know what my W212 uses , until I de-pin some. Even WIS/EPC is not say very helpful at female terminal level.
I even buy some from MB Indonesia a few each so that I can measure and see how they look like :A003 982 73 26 terminal female, 0.75 - 1mm, MLK 1.2
10-26-2022 | 05:00 PM
the female connector.
