Diagnostic Aids

When PCM is in backup fuel, rough idle and poor performance problems will exist. If DTC 17 is also stored, a problem with the 5-volt reference circuit or the sensor ground circuit may exist.

Fig 1: DTC 18 Schematic Pump Cam Reference Pulse Error

Fig 2: DTC 18 Flow Chart ("C" & "K" Series) Pump Cam Reference Pulse Error