1999 Jeep Grand Cherokee Transmission Faults: P0700 and P1790 Codes - Engine at 3000 RPM at 60 MPH
Hello, I'm experiencing issues with my 1999 Jeep Grand Cherokee. The vehicle shows diagnostic trouble codes P0700 and P1790. When driving, the engine reaches 3000 RPM while the vehicle only moves at approximately 60 miles per hour. This suggests a transmission shifting problem. I'm not sure what these specific codes mean or how to resolve them. Can anyone explain what P0700 and P1790 indicate in this context? Is my vehicle in limp mode? What should I check next, such as transmission fluid level or other related components?
Have you used an OBD2 scanner to retrieve the full diagnostic codes, including any additional P0700-related sub-codes or OSS (Output Shaft Sensor) faults? Any recent maintenance, repairs, or transmission work has been done? The P0700 code indicates a transmission control system issue, while P1790 points to a shift malfunction. Without full diagnostic data, it's hard to pinpoint the exact cause. Your vehicle may be in limp mode—this means the transmission is not shifting properly and only allows limited operation to get you home. Avoid over-revving the engine. Check the transmission fluid level and condition. A low or contaminated fluid could be contributing to the problem. Addressing these steps should help identify and resolve the issue.