Powertrain Controls - ECM/PCM

Trouble Code 17 Chart:

Camshaft & Crankshaft Sensors Wiring Schematic:

CIRCUIT DESCRIPTION
The camshaft position sensor is a "Hall-effect" switch located on the front of the engine. This sensor sends a signal to the Powertrain Control Module (PCM) indicating when to begin sequencing the injectors starting with cylinder number one. If the cam reference signal is not received by the PCM, the injectors will pulse sequentially, although proper sequencing may not occur resulting in a rough or unstable idle.

DIAGNOSTIC TROUBLE CODE (DTC) 17 WILL SET WHEN
Cam reference pulses are not detected by the PCM for 3 seconds while the engine is running.

ACTION TAKEN (PCM) WILL DEFAULT TO
The PCM will pulse the injectors sequentially though possibly not in the correct sequence. The malfunction indicator lamp (MIL) will not be illuminated.

DTC 17 WILL CLEAR WHEN
A current DTC 17 will clear when the cam signal begins to toggle. A History DTC 17 will clear after 50 consecutive ignition key cycles without a current DTC 17 being stored.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. The PCM performs a test for DTC 17 when the engine is running or during cranking.
2. By repeatedly "bumping" the starter, the camshaft timing mark and the camshaft position sensor will align with each other. At this point, the voltage from the sensor applied to the PCM should drop to near zero temporarily. This indicates that the camshaft position sensor is capable of sending a signal to the PCM.
3. Before replacing the camshaft position sensor, inspect the sensor for proper installation.

DIAGNOSTIC AIDS
An intermittent cam reference signal can be caused by poor connections, cracked sensor or internal engine problem.