I get P2138 (throttle positioning sensor) and P2127 (low voltage E) I have replaced the throttle body/positioning sensor .Car will go for about 3 days and get both check engine lights and power loss. Sometimes when I fill the tank they both go out. If I open and shut the gas cap the loss of power light will go off. I don't know what voltage output the two O2 sensors are supposed to do but #1 modulates quite a bit and #2 modulates but not as big a swing as #1. Driving me nuts.
I get 2 trouble codes P2127 and P2138. Replaced throttle body/pos.sensor on 2007 Saturn Ion
This is not an answer to your troubles but I have the same issue .. Car runs good..then..just shuts down..code was a throttle body code... Replaced throttle body and that did nothing..have you figured yours out yet?
1 more answer , 4 more comments
i have the same problem p2138 throttle/pedal position sensor/switch "d" "e" voltage correlation and p2127 throttle/pedal position sensor "e" circuit low input. car randomly dies sometimes runs good for a few days and sometimes when i first start it. have you found a solution yet? what car do you have by the way?
No but I have also changed the accelerator pedal/throttle sensor (the gas pedal). It's a 2007 Saturn Ion2. I am know looking for a short and maybe have it zeroed in. I t usually happens on a damp (heavy dew) or rainy day. I am looking at the connector attached to the firewall in the engine compartment. if I can get the damn thing apart with out removing the master brake cylinder (it's behind it). I'll clean it check the connections and try it. Ill post my results.
Im goint to try today to replace (tps) throttle position sensor, the one that is just before the intake manifold . shold also check grounding and input/output voltages. Try checking when car runs normal and when it is in limp mode may se where the issues are coming from? Not shure what state to check it in but I assume engine off with the ignition on. will keep posted of my progress.
the 2127 is actually the accelerator positioning sensor on the gas pedal. it's a short in the system somewhere. have to see where "E" circuit goes to.
Mines was a dam bad battery start with your battery 1st lol