Transmission automatic shifts rough 2003 Saturn ion

Asked by Jun 02, 2017 at 02:11 AM about the 2003 Saturn ION Base

Question type: Maintenance & Repair

Jerks hard from1st through 3rd

2 Answers


Would you scan for codes? Go to AutoZone and have them scan for free. How many miles on her?


There is no 'protect' mode for the transmission, tcm or ecm. If you see the reduced power mode indicator, the engine computer (ecm) is alerting you to a serious problem with the drive by wire system - the APP (pedal), TAC (throttle body) and wiring. Reduced power mode is not a transmission limp home mode. If, for any reason, a disruption in electrical connections or electronic communications should ever occur between either the APP or TAC and ecm the ecm defaults to a program termed 'reduced power mode' as the ecm determined it has no valid feedback signals from either the pedal or throttle position sensors (four sensors). The ecm will not allow full engine power but just enough to drive/limp off a highway to a safe place to make the emergency call instead of dying on the road. Reduced power or 'limp home' mode is the programmed default for drive by wire systems and a well designed safety net against any thoughts or possibilities of a runaway engine. Think California Toyota Lexus deaths resulting in the car supposedly having a runaway engine with its drive by wire system when it was determined to be a dealer installed aftermarket floor mat bunching up and causing the pedal to stick wide open. The deaths supposedly by an uncontrolled drive by wire system and investigation was followed world wide by every car manufacturer using drive by wire systems (including me). If you experienced and can verify reduced power mode you may have more than one problem, considering the high mileage (my guess) with several error codes. Reduced power mode, as mentioned, has its own list of possible causes while P0700 indicates the tcm sent an error code to the ecm to turn on the check engine light. The tcm is merely communicating an error with the other transmission error code(s) pointing to a specific area or part. And to complicate things, the possible remaining error codes are related to engine problems. At the least, three areas need to be addressed. Personally, high mileage may be one indication of long term wear and tear of EFI system and transmission parts that may need a closer look into what's worn and contributing to the overall symptom of poor transmission shifts/reduced power mode. I believe the engine problems (reduced power mode) should be addressed first as the transmission is the slave to how the engine performs - a poorly running engine won't allow automatic transmissions to operate correctly. Worn transmission parts are usually solenoids and leaking seals. P0171, P0174 and P0507 are engine related issues that may be simply worn out parts like the O2 sensors. P0507 may be a dirty throttle preventing proper commands from moving the throttle plate and the feedback sensors aren't matching expected responses from the ecm. Any hoses deteriorated, allowing vacuum leaks? Dirty maf sensor or vacuum leak between the maf sensor and throttle? P0971 is a transmission error code pointing to the line pressure control solenoid

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