Diagnostic Aids

WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Check for the following items:

A loose or missing distributor hold down bolt
A loose CMP sensor causing a variance in the sensor signal
An incorrectly installed distributor - 1 tooth off in either advance or retard positions
A loose distributor rotor on the distributor shaft
Excessive free play in the timing chain and gear assembly

If an intermittent condition is suspected, refer to Intermittent Conditions .

DTC P0016

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1	Did you perform the Diagnostic System Check-Engine Controls?	-	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Install the scan tool. Start the engine. Use the scan tool in order to monitor the engine speed. Does the engine speed fluctuate, up to twice the desired RPM?	-	Go to Step 3	Go to Step 4
3	Replace the crankshaft position sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Did you complete the replacement?	-	Go to Step 10	-
4	Perform the Camshaft Retard Offset test procedure as follows: Install the scan tool. Start the engine. IMPORTANT: The camshaft retard reading will not be accurate below 1,000 RPM. Raise the engine speed to 1,000 RPM. Monitor the camshaft retard with the scan tool. Is the camshaft retard reading within the specified range?	-20 to +20 degrees	Go to Step 5	Go to Step 6
5	Note the camshaft retard reading from the previous step. Raise the engine speed to 2,000 RPM. Does the camshaft retard reading change more than the specified value?	2 degrees	Go to Step 6	Go to Diagnostic Aids
6	With the engine at operating temperature and the engine OFF, perform the following procedure: Remove the distributor cap. Grasp the distributor rotor and gently attempt to rotate the rotor. Does the rotor turn on the distributor shaft?	-	Go to Step 8	Go to Step 7
7	Check for proper installation of the distributor. Repair as necessary. Refer to Distributor Inspection . Did you find and correct the condition?	-	Go to Step 9	Go to Step 8
8	Replace the distributor. Refer to Distributor Replacement . Did you complete the replacement?	-	Go to Step 9	-
9	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 10
10	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK