Hello, I have been troubleshooting code P2102, which is a code I have had come up in the past, so I put a new genuine Toyota throttle body on it, but that did not solve the check engine light and limp mode issue. As I was checking wiring, including looking for continuity and load testing the wire back to the ecm (with ecm harness disconnected), then I put the ecm connector back on and reconnected the battery, the code was gone and limp mode was gone, but after allowing the engine to idle for about 10 minutes, a flashing check engine light appeared and code P0302 for cyl 2 misfire, and no more P2102 code. Live data showed a rapid mis on cyl 2, which could be physically felt as well.
As I began to troubleshoot the misfire, I swapped the coil w/ another cylinder, then the spark plug, but no change. I also verified spark with the coil out of the cylinder. With the engine running and a stethoscope I can hear the injector clicking, and it sounds just like the other injectors...but I also checked continuity back to the ecm on the injector wiring and checked for 12 volts with a load (test light) on the power wire of the injector harness, so everything seems to check out, aside from actually pulling off the fuel rail and testing the injector out of the vehicle...which I would have done next, but after I was done testing wires and put the ECM connector back on and restarted the vehicle, the P0302 code is gone and it is no longer misfiring, but the P02102 code for the "throttle control circuit low" is back.
This has happened to me in the past when chasing other issues on this vehicle. Is there a known issue with the ECM connector where it may not establish good contact with all the female pins in the connector harness, which results in codes for "circuit low" or "circuit open" on various systems each time you pull off the ECM connector? I have cleaned the contacts of the ecm connector with plastic-safe electrical cleaner spray (allowed it to dry), as well as the male ecm pins, just fyi.
If not, then maybe I need to get back to troubleshooting the throttle body/wiring again, but everything has checked out, and this is a brand new genuine toyota throttle body on there now.
Thanks!
As I began to troubleshoot the misfire, I swapped the coil w/ another cylinder, then the spark plug, but no change. I also verified spark with the coil out of the cylinder. With the engine running and a stethoscope I can hear the injector clicking, and it sounds just like the other injectors...but I also checked continuity back to the ecm on the injector wiring and checked for 12 volts with a load (test light) on the power wire of the injector harness, so everything seems to check out, aside from actually pulling off the fuel rail and testing the injector out of the vehicle...which I would have done next, but after I was done testing wires and put the ECM connector back on and restarted the vehicle, the P0302 code is gone and it is no longer misfiring, but the P02102 code for the "throttle control circuit low" is back.
This has happened to me in the past when chasing other issues on this vehicle. Is there a known issue with the ECM connector where it may not establish good contact with all the female pins in the connector harness, which results in codes for "circuit low" or "circuit open" on various systems each time you pull off the ECM connector? I have cleaned the contacts of the ecm connector with plastic-safe electrical cleaner spray (allowed it to dry), as well as the male ecm pins, just fyi.
If not, then maybe I need to get back to troubleshooting the throttle body/wiring again, but everything has checked out, and this is a brand new genuine toyota throttle body on there now.
Thanks!
Oct 14, 2026 at 9:56 AM