Code 26, Quad-Driver Circuit 3.8L: Notes

Each PCM Quad-Driver Module (QDM) has a fault line which is monitored by PCM. PCM compares voltage values of fault line with acceptable values in PCM memory. If PCM senses values other than accepted values, a Code 26 will set.

Some QDM circuits will normally cycle between high and low, such as when brake pedal is depressed. Some scan testers may set a false Code 26 if engine is running, tester is installed and brake pedal is depressed for more than 30 seconds.

1. PCM does not know which controlled circuit set Code 26, so this chart checks each circuit to determine which is at fault. This step tests SERVICE ENGINE SOON light driver and circuit.
2. This determines which circuit is out of specification.