I was out of town for almost two weeks. When I came back and started my 2011 E350, I noticed the outside air temperature read as "--- * F" and that the check engine light was on. The next day, the air conditioner stopped working.
The dealer wants $500 to diagnose and change two sensors (the OEM sensors are $20 on Amazon). What is the likelihood that all three of these issues are tied to a bad ambient temperature sensor? If so, where might I find it?
You can use the $500 to buy your own scanner (they are several available in $150-200 range) and DIY scanning.
You will save lot of time avoiding driving to dealer, but then you will miss free car-wash and possible donuts.
AC operates by taking data from chain of at least 7 sensor.
You break 1 link in the chain........
You can use the $500 to buy your own scanner (they are several available in $150-200 range) and DIY scanning.
You will save lot of time avoiding driving to dealer, but then you will miss free car-wash and possible donuts.
The dealer's less than two miles away, so I take advantage of those free car washes and fresh cookies fairly regularly. The $500 is probably to recoup their costs for those.
I might take it to Autozone for a free scan. The a/c must be related to the outside temperature sensor since it stopped working around the same time the outside temp started showing as "---," right? Any idea how I get to that sensor?
Start with checking the wire harness. Those thermometers don't go out just becouse.
With new technology locating the sensor becomes harder and harder. Here is what google shows https://images.search.yahoo.com/yhs/...&hsimp=yhs-001
It is likely that dashboard and ECU use different sensors, so since you have $500 burning your pocket, let the dealer worry about it.
Start with checking the wire harness. Those thermometers don't go out just becouse.
Would that cause it to read "---" as the temperature? That would be ideal, because I really don't want to spend any money on this if I don't have to. Unfortunately, I don't have a lift and can't just check it myself, so I'm going to have to take it somewhere.
The outside probe is mounted in front bumper, so lot can be done by driving car on some bricks or planks.
ECU probe can be separate on engine intake, or can be part of MAF, but that is where you need a scanner to narrow possibilities. I am not familiar with this engine, but hopefully other members will chime-in.
Are you changing your mind about leaving $500 with the stealer?
The outside probe is mounted in front bumper, so lot can be done by driving car on some bricks or planks.
ECU probe can be separate on engine intake, or can be part of MAF, but that is where you need a scanner to narrow possibilities. I am not familiar with this engine, but hopefully other members will chime-in.
Are you changing your mind about leaving $500 with the stealer?
Where in the bumper might I find it? I'd love to take a look before I take it to anyone... I don't really want to spend $500 with the stealership (or with anyone else, for that matter).
I still wouldn't start taking car apart without scanning.
When logic programs on W212 are still a lot of blank page, on older models bumper probe would never trigger CEL.
Meaning I think you have more problems that can hide under front bumper.
Since you tend to keep the $500 in your pocket, back to the question >>> why not spend $150 of it on scanner?
I still wouldn't start taking car apart without scanning.
When logic programs on W212 are still a lot of blank page, on older models bumper probe would never trigger CEL.
Meaning I think you have more problems that can hide under front bumper.
Since you tend to keep the $500 in your pocket, back to the question >>> why not spend $150 of it on scanner?
I took it to a trusted local shop and they scanned it (as expected) with a faulty ambient temperature sensor. They replaced the sensor (one hour labor and $70 for the OEM part, they wouldn't use the $20 aftermarket one). Immediately, the outside temperature began to show again and the CEL went off. But the a/c didn't work.
Knowing the computer may need a few cycles, I took the car home and drove it around. This morning, I drove it to an appointment and the a/c started working about halfway there. Knock on wood, it has been working consistently since.
Total cost around $250 (this is almost exactly half what the dealer would have charged). Could I have done it myself for cheaper? Sure. But, the time it would have taken me to try to fix it without a lift and in a neighborhood where the HOA doesn't allow working on cars in the driveway would have been more valuable than what I paid for diagnostics and labor, so I consider it a good deal.
Bottom line: Replaced ambient temperature and all the symptoms resolved, but the a/c needed about 15 hours to recognize the new sensor and start working again.
So no car wash and no donuts? Darn I was hoping for pictures
Good to hear it is working again and I just learned that on W212 bad AC will trigger CEL.
Well, my dealer doesn't require a service or anything for the free car wash, so I may go get one anyway.
And, just to clarify, the bad a/c itself doesn't trigger the CEL. The faulty temperature sensor trips the CEL, and the a/c stops working because of the sensor.
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