FixVault

Code 79, Transmission Fluid OVERTEMP: Notes

WARNING: This page is about a different car, the 1994 Cadillac Fleetwood. However, it is still accessible from the selected car via links, so may be relevant.

PCM supplies and monitors a 5-volt reference to sensor. As transmission temperature changes, sensor resistance changes, affecting monitored voltage. When fluid is cold, resistance is high, resulting in a high monitored voltage.When fluid is hot, resistance is low, resulting in a low monitored voltage.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. Checks for out-of-calibration sensor or shorted circuit.
  2. Simulates Code 59.