Hello all, I’m having a problem with my 2008 TL Type S (~130k miles). I poked around the forums looking for some thoughts, but nothing quite covers what I’m having issues with. I find threads on each of my issues, but there doesn’t seem to be anything in common with the solutions. The fact that I’m having several failures all at the same time makes me think there is ONE module/sensor that is crapping out.

While driving around today, the car reported an error : “P2138 Throttle may not operate properly. Acceleration may be reduced.” The check engine and VSA lamps lit up. And indeed, the throttle was reduced to something like 1500 rpm. Luckily I was close to home and limped in. When I turned off the ignition, the key would NOT return to the 0 position, so I couldn’t get the key out. It was as if the car was still in gear, but it wasn’t. This prevented the car from being powered off, so I disconnected the battery. At that point, I could turn the key and remove it. (assuming the ignition cylinder solenoid was de-energized)

I left the battery disconnected for a few minutes in hopes of “resetting the computer.” When I hooked everything up, the engine started perfectly, but I then got a “P1109 Error : There may be a problem with your emissions system.” I turned off the engine and again had the same problem removing the key. I disconnected the battery again, and was able to remove the key.

Long story short, I did this a couple more times and got subsequent errors. “P2628 There may be a problem with your emissions system” and then “P2631: There may be a problem with your emissions system.”

So things went south and I’m trying to figure out what the problem is. In the course of 20 minutes, the car went from running perfectly to having multiple errors, limited throttle and a stuck ignition key.

Today was the first really hot day in the area, and I’m thinking some electronics are crapping out due to the added heat/stress. Power Control Module? Engine control computer? TPS sensor? Accelerator pedal position sensor? Maybe the WTF sensor?

Any thoughts? Thanks in advance…

JP in Mass

 

When having "unusual" codes getting help from service manual is a first step.

"DTC P2628: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) LABEL Circuit High Voltage"
P2631 is the same thing, but related to bank 2 (front of the engine).

Now the difficult part is that both of those codes coming back don't make too much sense right now. So I looked for any common thing between all the codes that you listed.

DTC P1109: BARO Sensor Circuit Out of Range High - that is barometric pressure sensor that is built-in into the ECM.
DTC P2138: APP Sensor A/B (Throttle Position Sensor D/E) Incorrect Voltage Correlation


Now the interesting part is that oxygen sensor connections related to P2628 and P2631, and app sensor code P2138, all connect to ECM using the same "Connector D (17P)".
Baro code also points to something being wrong with ECM itself.





ECM is our car is located under middle of the dash. Under the HVAC unit. And since you mentioned that it's hot in the area, AC is probably running a lot. That means water, and if the tube that is supposed to route the water outside of the car gets plugged it might be possible for ECM to get wet.




Actually, on this photo, you can see a black hose on the right. Without doing any research I'm guessing that it's the hose that is supposed to route water from AC system to the outside.

Are carpets around the front of the car wet by any chance? I would start by getting to the ECM and checking for signs of water ingress. Unplug that connector D and see if it's nice and shiny. When "clearing" codes preferably use a scan tool.
I never worked with those codes but that my bet based on information provided.

 

Thank you so much for the feedback. I'm picking back up now trying to repair. Will report back with the bottom line.

Thanks

 

You should check your battery and charging system first. A weak battery or failing charging system will throw a lot of codes so verify they are good before you dive into other troubleshooting.

 

^this