Code 18, Cam/Crank Error 3.8L: Notes

During cranking, ignition module monitors dual crank sensor sync signal. Sync signal is used to determine correct cylinder pair to spark first. After synch signal has been processed by ignition module, module sends a fuel control reference pulse to PCM. When PCM receives this pulse, it will command all 6 injectors to fire for one priming shot of fuel. After priming, all injectors are held off for 2 crankshaft revolutions to allow cylinder to use fuel from priming shot. After firing, PCM begins to operate injectors in sequential mode based upon true camshaft position. PCM expects to see 6 fuel control pulses for each cam pulse. If sequence of these pulses is incorrect 10 times consecutively, Code 18 will set.

1. Determines if conditions necessary to set code still exist.
2. If 5 volts are not present at PCM harness connector terminal, cam sensor may be interfacing with magnet in camshaft sprocket. Bumping starter should correct this problem.
3. If a failure is induced in fuel control reference circuit, 5 volts on circuit should change when faulty wiring or connection is manipulated.