2005 Subaru Legacy Speed Control & Cruise Problems

While driving, cruise control and check engine light comes on and then the car won't accelerate. Engine revs really high and when pushing accelerator pedal, car will not move. The check engine code states "throttle position sensor". This has happened more than 20 times

DRIVING SOUTHBOUND ON HWY 17 AT 60MPH 11/15/2020 ENGINE SUDDENLY WENT TO IDLE. THROTTLE BECAME UNRESPONSIVE. CHECK ENGINE LIGHT ILLUMINATED. I DRIFTED TO SAFETY OFF THE HIGHWAY. ENGINE STILL IDLING, THROTTLE UNRESPONSIVE. AFTER CHECKING UNDER THE HOOD, I RESTARTED THE CAR AND NORMAL THROTTLE RESPONSE RETURNED. I CAUTIOUSLY DROVE HOME AND READ THE CODE FOR THE CEL: P2138 -- THROTTLE POSITION SENSOR VOLTAGE CORRELATION. A QUICK SEARCH FOUND OTHERS HAVE SOLVED THIS PROBLEM BY CHANGING THROTTLE CONTROL TO AN UPDATED VERSION THAT USES HALL EFFECT METHOD INSTEAD OF A RHEOSTAT. I INQUIRED WITH PREVIOUS OWNER OF THIS CAR AND FOUND IT HAD HAPPENED ONCE BEFORE.

ENGINE ACCELERATED AT A RAPID SPEED ON ITS OWN POWER.. UNABLE TO STOP THE VEHICLE WITH THE BRAKES. VEHICLE WAS IN MOTION IN THE PARKING LOT..

WHILE PRESSING THE ACCELERATOR THERE WAS NO RESPONSE. THE CAR CONTINUED AT IT'S NORMAL IDLE, BUT PRESSING ON THE GAS GAVE NO RESPONSE. I WAS ABLE TO COAST TO A STOP OFF THE ROAD AND TURN THE CAR OFF AND BACK ON, WHICH FIXED THE PROBLEM THE FIRST TIME. THIS HAS HAPPENED AGAIN TWO TIMES AS OF TODAY AND IT TOOK SEVERAL TIMES TURNING THE CAR OFF AND BACK ON TO GET USE OF THE ACCELERATOR AGAIN. THIS SEEMS LIKE A SAFETY ISSUED, AND OF COURSE A PROBLEM THAT COULD EASILY LEAVE ME AND MY KIDS STRANDED OR INJURED IN AN ACCIDENT IF I WERE TRAVELING AT HIGHER SPEEDS WHEN THE PROBLEM OCCURS. I'VE READ ONLINE THAT IT SEEMS TO BE A COMMON PROBLEM WITH SUBARU. THE CODE THAT I RECEIVED WAS P2138 (THROTTLE POSITION SENSOR). *TR

TL* THE CONTACT OWNS A 2005 SUBARU LEGACY. WHILE DRIVING APPROXIMATELY 65 MPH, THE VEHICLE INDEPENDENTLY ACCELERATED. THE CONTACT HAD TO SHIFT INTO NEUTRAL AND SHUT THE VEHICLE OFF IN ORDER FOR IT TO RESUME NORMAL OPERATION. THE FAILURE RECURRED ON NUMEROUS OCCASIONS. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOT MADE AWARE OF THE FAILURE. THE VIN WAS UNAVAILABLE. THE APPROXIMATE FAILURE MILEAGE WAS 190,000.

TL* THE CONTACT OWNS A 2005 SUBARU LEGACY. THE CONTACT STATED THAT WHILE TRAVELING VARIOUS SPEEDS, THE VEHICLE SUDDENLY LOST ACCELERATION POWER. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOT CONTACTED ABOUT THE FAILURE. THE FAILURE MILEAGE WAS 110,000.

TL* THE CONTACT OWNS A 2005 SUBARU LEGACY. THE CONTACT STATED THAT WHILE ATTEMPTING TO ACCELERATE FROM A STOP, THE VEHICLE WAS SLOW TO RESPOND. THE RPM GAUGE MOVED DESPITE THE ACCELERATOR PEDAL BEING DEPRESSED AND THE VEHICLE THEN STALLED. THE VEHICLE WAS INDEPENDENTLY DIAGNOSED AS HAVING A THROTTLE BODY SENSOR FAILURE. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED OF THE INCIDENT. THE APPROXIMATE FAILURE MILEAGE WAS 146,000.

CRUISE CONTROL RANDOMLY DISENGAGES WHILE DRIVING UNDER NORMAL CONDITIONS, CAUSING A SUDDEN AND UNEXPECTED LOSS OF VEHICLE SPEED. *TR

CRUISE CONTROL ON 2005 SUBARU LEGACY WAGON IS INTERMITTENT OVER A RANGE OF OPERATING CONDITIONS (50-70 MPH, STRAIGHT/FLAT, SLOW/STEADY CURVE, UPHILL, HOT WEATHER, COLD WEATHER, ETC.). CANNOT PINPOINT TO ONE PARTICULAR COMBINATION OF OPERATING CONDITIONS. PERHAPS INTERMITTENT ELECTRICAL CONNECTION, BAD SENSOR OR COMPUTER CONTROL FAILURE. WHEN PROBLEM OCCURS, "CRUISE" LIGHT ALWAYS STAYS ON, BUT "SET" LIGHT TURNS OFF AND ENGINE LOSES ACCELERATION. RESUMING/RESETTING THE CRUISE CONTROL DOES NOT SOLVE THE PROBLEM. NOTIFIED MILFORD SUBARU (NH) DURING 22,500 MI SERVICE AND THEY COULD NOT RECREATE PROBLEM. NOTIFIED MILFORD SUBARU (NH) AGAIN DURING 30,000 MI SERVICE (THEY HAVE THE CAR NOW, WILL BE PICKING UP TONITE). HAVE NOT BEEN ABLE TO FIND NHTSA RECALLS OR SERVICE BULLETINS ON THIS TOPIC, BUT HAVE SEEN INTERNET MESSAGE BOARDS WHERE OTHER SUBARU OWNERS HAVE EXPERIENCED A SIMILAR PROBLEM WITH THE 2005 LEGACY.

UNDER NORMAL DRIVING CONDITIONS, CRUISE CONTROL DISENGAGES RANDOMLY CAUSING UNEXPECTED VEHICLE DECELERATION. *NM

2005 LEGACY 2.5I WAGON WITH MANUAL TRANSMISSION HAS ALWAYS HAD THROTTLE SURGE UNDER VERY LIGHT LOAD WITH CRUSE CONTROL ON. IS MOST NOTICABLE ON HIGHWAY GOING DOWN SLIGHT GRADE. WITH CRUSE CONTROL OFF, I ALSO CAN'T MAINTAIN DESIRED SPEED IN THIS SITUATION; MINIMUM AMOUNT OF GAS IS TOO MUCH, ANY LESS CAUSES ENGINE TO GO BACK TO IDLE AND THE CAR SLOWS TOO MUCH. DEALER SAYS THIS IS NORMAL. NOTE THAT THE CRUSE CONTROL HAS SUFFERED A SEPARATE PROBLEM (FAILED TO WORK, ALWAYS DROPPED OUT); THIS PROBLEM HAS BEEN REPAIRED AND HAS HAD NO EFFECT OF THE SUGING PROBLEM.