Download Tests/Procedures: Potential Causes: Tech Tips: 1. With the distributor unplugged and ignition on, check for power on the White/Red wire and ground on the Black wire. 2. If power and ground are good, check for a 5v reference on the White wire. 3. If the 5v reference is good, tap-test the White wire to ground with the key on and see if it fires the coil. If so, the distributor is bad. 4. If no 5v reference on the White wire, unplug the Air Flow Meter (AFM) and recheck. If now has 5 volts, the AFM may be shorted internally. If the AFM is not shorted, check the wire harness and powers and grounds to the Engine Control Module (ECM). Shorted Air Flow Meter (AFM) Defective Distributor Crank Angle Sensor Tapping the wire to ground simulates what the sensor in the distributor is supposed to be doing. If the AFM is shorted, there may not be a check engine light on with the key on and when the AFM is unplugged, the check engine light will come on.