I found these in the shop manual and may help you with some diagnosis:
DTC P0014
Circuit Description
The cam phasing system is a hydraulically actuated phase shifting mechanism. The powertrain control module (PCM) supplies the ignition positive driver and ground circuits. A pulse width modulated (PWM) driver controls the amount that the camshaft actuator solenoid assembly advances or retards the exhaust camshaft. The exhaust camshaft is commanded to a maximum retard position of 25 degrees. When the exhaust camshaft is retarded at the maximum rate, the duty cycle of the signal is at 100 percent. The maximum advance rate has a 0 percent duty cycle. Other than when the camshaft is at full advance, a 50 percent duty cycle is used to maintain a steady retard angle.
If the desired and actual cam phase angle error exceeds its tolerance value for a certain amount of time, then DTC P0014 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0014 Exhaust Camshaft Position (CMP) System Performance
Conditions for Running the DTC
• The engine is running.
• The PCM has enabled the cam phaser.
• DTC P0014 runs continuously when the above conditions are met.
Conditions for Setting the DTC
• The vehicle must be driven.
• The difference between the desired CAM phase angle and the actual CAM phase angle is more than 3.5 degrees.
• The CAM phaser is steady for 12.25 seconds.
• The condition is present for 12.25 seconds.
Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
• The scan tool cam phase control function increments the cam phaser in 10 percent increments. Each increment equates to 2.5 degrees of cam phasing. A cam phase angle of 15 degrees is achieved by commanding the phaser with the scan tool to 60 percent.
• Inspect any engine mechanical work that has been performed recently. Verify that the engine timing has not been altered.
• If this DTC is set along with any crankshaft position (CKP) or camshaft position (CMP) sensor DTCs, then both the CKP and CMP sensor DTCs should be diagnosed prior to performing this diagnostic. The PCM uses both inputs to determine the actual camshaft position.
• Check the following items:
- A loose CMP sensor causing a variance in the sensor signal
- A loose CKP sensor causing a variance in the sensor signal
- Excessive free play in the timing chain and gear assembly
- Debris or contamination interfering with the camshaft position actuator solenoid valve assembly
- Debris or contamination interfering with the camshaft position actuator assembly
• Engine oil has a major impact upon the camshaft actuation systems responsiveness. Oil temperature, viscosity, and quality can slow and/or inhibit the phaser's ability to reach a desired phase angle.
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Document ID# 1809545 2005 Chevrolet TrailBlazer - 4WD
Subject: DTC P0014, P0017, and/or Belt Noise - Inspect Actuator Solenoid and Crank End Play - keywords bearing cam chirp damaged debris internal light metal P0106 phaser replacement run SES squeak thrust #PIP3693B - (04/04/2006)
Models:
2005-2006 Buick Rainier
2005-2006 Chevrolet TrailBlazer
2005-2006 GMC Envoy
2005-2006 Saab 9-7x
with 4.2L Engine (VIN S - RPO LL8)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
On rare occasions, a rough idle may be encountered with a P0014 and/or P0017 DTC. Due to the rough idle, a P0106 DTC may be stored too. This concern may be due to debris in the camshaft actuator system, which may be caused by a missing camshaft actuator solenoid screen or a worn crankshaft thrust bearing. Typically, this is the result of a camshaft actuator solenoid concern. If this is due to a worn crankshaft thrust bearing, some customers may also comment on a drive belt noise.
Recommendation/Instructions:
If this concern is encountered, follow the SI diagnostics and repair as necessary. If the SI diagnostics do not isolate the cause of this concern, ensure that camshaft actuator solenoid screens 1, 2, and 3 are in place.
(1) Screen for Advance Pressure to Camshaft Actuator
(2) Screen for Pressurized Oil from Oil Pump
(3) Screen for Retard Pressure to Camshaft Actuator
If any of these screens are missing, replace the camshaft actuator solenoid, change the engine oil and filter, and evaluate the concern.
If all these screens are present, measure the crankshaft end play to determine if it is within the specification of 0.0044" - 0.0153" (0.112 - 0.388 mm). Typically, if excessive crankshaft end play is causing this concern, it will be obviously out of specification by .050" or more. If crankshaft end play is within specification, replace the camshaft actuator solenoid.
If the crankshaft end play is obviously out of specification, inspect the engine block for damage due to contact with the crankshaft.
If there is no engine block damage present, disassemble the engine and inspect the following components for damage due to thrust bearing debris in the engine oil: all bearings, all journals, all valvetrain components, all timing components, and the crankshaft