2008 CX9 has codes P2101, P2104, P2110, P2111 and P2112

Hi all,

I'm new to the forum so let's see how this works out. I have a 2008 CX9 and I've had to replace the throttle body 5 times from January '22 to today (March 17, 2022). Each and every time I get codes P2101, P2104, P2110, P2111 and P2112, which from what I can tell are all TB related. The TBs don't go to catastrophic failure immediately. It might fail once one week and recover after a few minutes, then two or three times the next week, then every morning until it doesn't recover at all. I then replace with a remanufactured one from Cardone. I have never tried new, since they have no warranty here being electrical, and are very expensive from the dealership. When they start failing I can either turn the engine off wait a while and it's gone if that doesn't work I will leave it idling for a long while and it slowly goes away. This works most of the time until it just doesn't recover anymore. Codes are very difficult to clear having to repeat the clear several times. Disconnecting the battery will only clear codes occasionally. It will always have both the check engine light and wrench light on. My thoughts are that either the Cardone remans are not that well repaired (I get them from Rock Auto) or the ECM (engine control management) is bad and damaging the TB. I've checked the wiring and connector plugs. Another interesting thing is that twice, after turning the engine off during separate occasions, the A/C will turn on and only turn off if I turn the switch to start without starting or pull the neg cable from the battery... weird. After replacing the TB the CX9 will work ok for a few weeks maybe a little over a month and start failing again. Since the codes are very specific to the TB I haven't tried any other thing. Any ideas or help is good and worth trying. Big thanks in advance!!!
2009 Mazda CX-9 GT
TB don't typically fail, and the fact that you have changed the same part 5 times makes me believe that the TB isn't the issue. Sounds more like the electronics attached to it or that control it is what your problem is.

P2101: generic code for the engine control module (ECM) detecting the throttle actuator control (TAC) went out of the range of the circuit causing an open circuit to be detected in the TAC motor.

P2104: generic code for the engine control module (ECM) detecting a major failure in the throttle actuator control (TAC) system causing the ECM to go into failure mode forced idle and limiting the engine to an idle RPM limit only. The throttle will not respond to any increase in throttle.

P2110: generic code for the engine control module (ECM) detecting a major failure in the throttle actuator control (TAC) system causing the ECM to go into failure mode and limiting the engine to a specified RPM limit.

P2111: diagnostic trouble code (DTC) for "Throttle Actuator Control System - Stuck Open". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation.

P2112: general diagnostic trouble code indicating a fault with the throttle actuator control system. This code may be seen with other throttle body codes. The P2112 code tells us that the throttle body actuator control system has found a stuck closed throttle plate.

Speaking generically, these are some components that could be causing your issue.....

ECM (computer)
TPS (throttle position)
APP sensor (accelerator pedal position)
throttle actuator control motor
MAF (mas air flow)
dirty/corroded/faulty connector

I think your next step is to get the operating values of these components, grab a voltmeter and start testing. TPS, MAF and APP would be the first ones I would start with.
Hope all is well. I will get the electrical specs for the APP (should be somewhere near the gas pedal, I suppose?) and for the MAF. I did read a thread where replacing the MAF did the job with a similar issue but that included a MAF code. The connector is not crispy clean but seems to be ok (looked at it up close enlarging a pics). The TPS and Throttle control motor are both sealed (for warrrant sake) inside a module that is part of the TB, so if I would find that those are bad I'd have to replace the TB altogether anyway, which would bring me back to square one. All the codes I mentioned show up when scanned and seem to be either mechanical or electrical but related to the TB and module. Again, I will look at your recommendations, which are very sound. Could be that one problem drowns out another. Keep you posted with my findings for future reference of other members. Tons of thanks!!(y)(y)
Hi there,

I have an update. I got some values for the APP and MAF from the shop manual. The MAF was DOA. I tested it several times on the vehicle and twice off it, getting a flat line output every time. I also tested the connector just to be sure I it wasn't a bad connector. So I got new one (not a rebuild). Replaced it with the battery disconnected, while at that I took the connector apart and tested it again to be sure. I also replaced the TB with one that was intermittent but had only failed twice . Reconnected everything and turned the switch. It turned the engine on although it ran a little rough for few minutes but then stabilized. I graphed and monitored the outputs for about a half hour, shut it down let it rest for 15 minutes and cranked it again. All seemed ok and it was stable for another half hour until I started adding load to the engine, lights, radio, A/C and shifting... After going through the shifts a few times I got the throttle outputs started jumping while the input signal was flat.
I then turned it off and restarted the engine a few time getting the same bad outputs. Turned the engine off, pulled the TB connector and reconnected it. Same problem when I turned the engine on. Pulled the plug again and flushed it with electrical contact cleaner specific for plastic connectors. Put the connector back in and it started as if nothing was wrong. I let it run for about 15 minutes when all of a sudden the engine shut down buy itself. I checked the graphs I was monitoring, all were smooth. Checked for codes but none were stored. Now, when I started the engine again I had the crappy output again and now both the service engine and the wrench lights on. MAF is still good. I cleaned the connector again twice but no luck. I ordered the TB connector plug since the wires have kinks and are brittle, just in case.
That about sums it up. Meanwhile I'm trying to find out how to test the TB off of the engine.