Code 26: Quad-Driver Circuit: Notes

WARNING: This page is about a different car, the 1990 Oldsmobile Cutlass Cruiser, 1990 Oldsmobile Cutlass Ciera, 1990 Oldsmobile Cutlass Calais, 1990 Buick Skylark, and 1990 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

Each ECM Quad-Driver has a fault line which is monitored by the ECM. The ECM compares voltage values of the fault line with acceptable values in ECM memory. If the ECM senses other than accepted values, a Code 26 will set. QDM 3 will not set a Code 26.

NOTE: Test numbers refer to test numbers on diagnostic chart.

The ECM does not know which controlled circuit set the Code 26. This tests SERVICE ENGINE SOON light driver and circuit.
QDM SYMPTOMS:
- TCC inoperative.
- Hot light on all the time, off during bulb check.
- Cooling fan on all the time or will not come on at all.
- Poor driveability due to 100 percent canister purge.