Codes P0301 P0223 P0122 P02135

Ozarks Driver

Looking for a place to start. I have read several throttle position sensor threads without finding what I am looking for, possibly because my search skills are poor.

I was driving in city traffic a couple of days ago when my 2010 370 with 105,00 miles developed a dead miss. I already had the plugs as it was due for them to be changed and at first I thought a plug had given up the ghost. I installed the plugs, and all were ready for replacement but showed only normal wear. I moved the throttle bodies out of the way with the wiring connected and do not believe I put excessive force on the harness. When I restarted the engine the miss was still present. I scanned the system and found P0301 (misfire cylinder 1), P0223 (throttle/pedal position sensor/switch B circuit high input), P0122 (throttle position sensor A circuit low input),and P2135 (throttle/pedal position sensor/switch A/B voltage correlation).

I replaced the coil this morning and eliminated the miss, the engine is idling very smoothly. When I press the accelerator the RPM's go to 1200 and then drop back to 1,000. I did/attempted the throttle position sensor reset (ignition to run without starting the engine and fully depress the pedal fully 5 times in less than 5 seconds) with no success. The battery has been disconnected several times for 30 minutes to over an hour in the course of work.

Where are some places to check and what might I have done to cause this problem? Both throttle body plugs seem to have tight connections, no corrosion, and have dielectric grease in them. Are there any connectors in the harness I might have pulled loose? The wires I can see without unwrapping show no visible cracks or other damage. Everything is stock. Thanks in advance.

SouthArk370Z

My first guess is that you didn't do the relearn procedure quite right - IIRC, it's very picky about timing. Several threads on this site or you can download a copy of the FSM (link in my sig) to get the official procedure,

My second guess would be a wiring problem - check the continuity of the wires going to/from the TBs.

Most problems can be solved without disconnecting the battery. But if you need/want to do it anyway, pressing on the brake pedal for 2-3 seconds will discharge all the capacitors and other storage devices in the system. No need to wait hours (or even minutes).

Edit: Disconnecting the battery will cause the ECM to lose some tuning params and you might lose radio presets. Some MYs require a window reset, too. You will also reset the ready state on the emissions system and will have to do several drive cycles to get it back to ready. IMNSHO, it's best to avoid disconnecting the battery, if possible. YMMV

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JIN2012

So back during my 350Z HR days I had similar problems with what I thought were my throttle bodies due to the codes saying there was an issue with the throttle position sensor. I tried a sparkplug change, the relearn procedure, replacing the throttle bodies...To make a long story short, I took it to the dealer with a used ECU to give that a shot and sure enough it was the ecu that had gone bad. The tech mentioned that water got through the grommet in the engine bay and got the ecu wet.