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cx-9 2010 ecm Looses connection with every other modules as soon as it rains.
I recently purchased a 2010 cx-9 with 200,000kms on it. Its awesome! The car works great! But not when it rains. When it does rain, the ecm Looses contact with every single computer on the car, bcm, tcm, fan, cluster, seats etc. Symptoms are: hard shift, stuck in 3rd Gear (because if the tcm), cluster not working (vehicle speed data invalid), fans goes nuts, every lights IS on in the dashboard. I took apart the ecm but there isnt any water damage. Still sealed it good though. I looked at the most obvious connections/grounds and put Grease on them. I got two scrapyard computers that I will try later on once I program the keys to it. Is this a known issue please help me!
here is the link to a video i took of the issue: https://youtube.com/shorts/HEA7bJccdow?si=8ZI-sD4lvO1YkU5C
Even though you didn't find any visible water damage, it's still possible that water might be getting into the ECM or other electrical connections. Water can sometimes cause intermittent issues without leaving obvious traces. Check that all connections and seals are intact and in good condition.
So first thing is to get a REAL Diagnostic scanner and NO BLUETOOITH.
Then go you your OBDII diagnostic connector plug in the diagnostic scanner
Then start over!
The first thing to do is note all the DTC then go to monitors and note which are not READY.
Then go to pending DTC which is different from active DTC and note them.
Then reset EVEYTHING also the Monitors. Don't worry the pending file remains until the problem is solved.
Once you do a completely cold start as soon as the engine check light appears quickly connect to the OBDII connector and get the active DTC.
The other very important thing to do is to check the battery health and the terminals on the battery as well the starter lead and especially the ground lead.
Checking the health of the battery means having it properly load tested. Please don't comment the age of the battery it is useless information!
If you insist and continue to use a blue tooth device ...well good luck with that and you will likely at some point, be towed to a service shop.
__________________________________________________ __________________________________________________ __________ Chubby As for water getting into the ECU .... I highly doubt that is what is happening as you would get ECU failure and not what you are reporting if we could believe the Bluetooth device used for reporting.
You would have been better "GUESSING" that it is a failing ECU then water damage as how the problem is described on that year ECU
Look Chubby I have read a few of your responses and they are not bad information, but you are in the wrong time period. You have to shift from what you knew prior about 1995 will give a little benefit of doubt to say 2001 to present. The systems on these platforms have changed drastically and old school wisdom very seldom applies anymore.
Honestly if you were a Certified Automotive Technical (mechanics are altogether different) but your last current certification was older then 20 years ago I am not sure I would hire you?
cx-9 2010 ecm Looses connection with every other modules as soon as it rains.
