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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Automatic Transmission - Diagnosis - 4L80-E >> Diagnostic Charts >> Code 68 - Overdrive Ratio Error >> Diagnostic Aids

Diagnostic Aids

Check transmission pass-through connector. Code 68 will set if transmission defaults to 2nd gear. If problems are still present, check for possible internal transmission problems.

Fig 1: Code 68 Troubleshooting Diagnostic Flow Chart
G92F14113Courtesy of GENERAL MOTORS CORP.