Output Codes/Tests

In addition to tests related to input sources, the control units are also capable of generating certain output signals to test the operation of various components. During each test, a code will be displayed from the engine warning light in the instrument cluster to identify the test being performed. The test sequence must be run from the beginning each time; a test cannot be repeated, and an individual component cannot be tested out of sequence.
To begin the output test sequence:
1. Turn the ignition OFF.
2. Insert a spare fuse into the socket on top of the fuel pump relay.
3. Turn ignition ON.
4. Close the full throttle switch to activate the indicated test.
Note; If the ignition is turned ON before the fuse is inserted, or if the starter is operated after the fuse is inserted, the control unit will automatically switch to input testing.
The four output tests are, (in order):
1. 4341 Differential pressure regulator
2. 4343 Charcoal canister shut-off solenoid
3. 4431 Idle stabilizer valve
4. 4443 Cold start valve