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Discussion Starter #1
Longtime lurker requesting some advice...

History:
I purchased a 2006 MDX w/112k in June of '15. Immediately changed all fluids (all OEM), spark plugs, timing belt, water pump tensioners, etc. I also added a class III tranny cooler (bypassing OEM cooler), a P/S cooler and an OEM tow hitch. Vehicle has been very reliable, save one incident in September of last year that was similar to my current issue, but easily resolved.

Current problem:
On Sunday, August 7 The fam and I took the Acura to church then had lunch and did some shopping on our way home. Leaving our last stop, the Acura displayed CEL, VTM-4 and VSA lights. I carry with me in my car (since the Sept '15 incident) a Wi-Fi OBDII adapter (https://www.amazon.com/gp/product/B00HVV60HI/ref=oh_aui_search_detailpage?ie=UTF8&psc=1) which I promptly popped into the OBDII port. The code was u0107. In the Sept '15 incident I had three codes, two of which pertained to the APP sensor and the third I can't recall, but I want to say it was something very vague referencing the PCM. In that incident I was advised by a very helpful dealer service manager to clear the codes and see if they come back and, if so write them down and call him (they were 8+ days out so it was that or wait...). Given that history, I noted this code and attempted to clear it. The code came back. Tried a few more times, no joy. Limped home.

FF to yesterday, I tried checking the electrical connection going into the throttle body after reading this post: http://www.mdxers.org/forums/73-first-generation-mdx-2001-2006/52770-u0107-cautionary-tale.html and found that mine was indeed already correctly fastened. I also checked fuse #7 15A in the fuse box near the air filter housing and it looked good. I then disconnected the air intake from the throttle body so I could see the throttle and verified that it does move if poked with my finger (I figured it would as the car was just driving fine). I took a video of the throttle (I was working alone) as I tested the service manual procedure for holding down accelerator and turning key to position II (*** ignorance alert *** I'm 99% sure this is the key position right before you engage the starter?). The throttle didn't move during the test. I re-attached the intake and was about to give up when I decided to see if I could access the relay for the throttle (under dash, passenger side - very difficult to get to). I pulled the neg(-) battery cable and removed glove box and some trim and could get my fingers on the relay, but couldn't get it out. Tried to catch the edge with a flat head screwdriver and get it out but was afraid to damage it so I abandoned that. Pushed on the top to ensure that if I had loosened it, it would be properly seated again (though the bugger didn't really move from what I could tell). Resigned myself to defeat and put the interior back together. Re-connected the neg(-) cable and, low and behold, the 45 minutes or so I had it disconnected somehow cleared things out and the car fired right up, throttle fully functional and I was able to test drive it around neighborhood. During the test drive the red battery symbol came on a few times as I let off the accelerator, but I'm not sure if this is because I forgot the Wi-Fi adapter in the car for several hours on Sunday (it was nice and warm when I removed it). Side note: alternator was just locally rebuilt by a local re-builder and batt was about $120-$130 from AutoZone last year. Came home from test drive, did the idle learn procedure (no HDS, but maybe the car still benefits from the proc?) and turned it off, turned it on, worked great. Shrugged shoulders. Went to bed with intentions to take the car to work next day (normally leave it for the fam). Went to start the car this morning & the code was back immediately - almost as if the car has sensed the throttle was missing at some point in the last 12 hours and already logged the code. Clearing it had (as expected) no benefit.

Pics attached: 1) Torque showing data from this morning (engine was running and my foot was fully on the accelerator when I took this screen grab - note: no throttle), 2) Dash lights FWIW

Two last pieces of info:
1) About a week or so before this happened, the built in button to operate the garage door stopped working. I was going to check on that when I had time (in the middle of house remodel stuff) but just grabbed a clicker I use for my motorcycle and had my quick fix.
2) When checking the electrical connector to the throttle body, I noted that two of the nuts holding the throttle body in place on the intake had a Sharpie line drawn across them. This indicates to me that at some point the throttle body was removed as I could see no other explanation for the markings.

So - question (finally - and I appreciate it for anyone who made it this far): Does anything obvious come to mind? What would you do? Continue to troubleshoot per the service manual (which I have available) testing for shorts and opens, etc? Cry uncle and take it in?

Thanks very much in advance and please let me know if you need any additional information, pictures, etc.

David
 

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Discussion Starter #2
Update my situation

I got home after work and tested the vehicle: still not working. I had a spurt of fresh optimism and decided to try to work through a few of the steps in the service manual (BTW, I did confirm where ignition spot II is - derp, shown right on the ignition...). I started by carefully jumping the SCS line with a paperclip. Turned ignition to position II. Codes were still lodged in the system. Took key out and went looking for the PCM connectors A and B. There were lots of pictures of the connectors in the manual, but I could not easily find a description of where they were located (I guess it must be common knowledge to everyone but me). I scoured the internet and also was not able to find any help. Finally I found a diagram in the manual indicating the PCM connectors were in the engine compartment near the washer fluid fill port and below the main fuse box. I was happy to find they were very easy to access. I unlatched connector A, but couldn't quite figure out how to get it off. I then unlatched B - same issue. There was a zip tie on each connector that may have been serving as a lock. In any event, I put each connector back and made sure to really seat them well. Tested the car & voila, it started up and codes were cleared. I test drove it around neighborhood, and then drove it again a couple of hours later to pick up dinner.

I will post again (for other lurkers and FWIW to anyone who sees this) if the issue returns.
 
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