Powertrain Controls - ECM/PCM

DTC 17 Camshaft Position Sensor Circuit Error:

Camshaft Position Sensor Wiring Diagram:

Circuit Description:

The camshaft position sensor is a "Hall-effect" switch, located on the front of the engine. The camshaft position sensor sends a signal to the ECM when the #1 cylinder is on the intake stroke. This signal is used by the ECM to synchronize Sequential Fuel Injection (SFI) mode of operation with each intake valve opening. If the cam reference signal is not received by the ECM, the ECM will still pulse the fuel injectors sequentially, but the fuel injectors may not be in synch with each intake valve opening. That is, fuel injector timing may not be as accurate because the ECM does not know the exact time each intake valve is opening. A loss of this signal or extra (false) cam reference signals, above 500 RPM, will set a DTC 17.

Test Description:Number(s) below refer to circled number(s) on the diagnostic chart.

1. The ECM performs a test for DTC 17 when the engine is running or during cranking.

DTC 17 will set when:

^ Cam pulse is missing on the first pass through the internal ECM self test of the camshaft position sensor.

OR

^ Cam pulse is missing for 3 seconds.

2. By repeatedly "tapping" 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 ECM should drop to near zero temporarily. This indicates that the camshaft position sensor is capable of sending a signal to the ECM.

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. - Intermittent Malfunctions