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 speed is greater than 1,350 RPM. |
| • | The PCM has enabled the cam phaser. |
| • | The system voltage is greater than 11 volts. |
| • | 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 3.75 degrees. |
| • | The CAM phaser is steady for 3 seconds. |
| • | The condition is present for 3 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. |
| • | Inspect 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 CMP actuator solenoid valve assembly |
| - | Debris or contamination interfering with the CMP actuator assembly |
| • | Engine oil has a major impact upon the camshaft actuation system's responsiveness. Oil temperature, viscosity, and quality can slow and/or inhibit the phaser's ability to reach a desired phase angle. |
| • | If an intermittent condition exists, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||||
2 |
Does the Cam Phase Angle Actual remain close to the Cam Phase Angle Desired at all commanded positions? | -- | Go to Step 3 | Go to Step 4 | ||||||||||
3 |
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||||||
4 | Allow the engine to idle. Does the engine run rough or stall? | -- | Go to Step 9 | Go to Step 5 | ||||||||||
5 |
Is the engine oil level within operating range? | -- | Go to Step 6 | |||||||||||
6 |
Does the oil pressure gage indicate engine oil pressure less than the specified value? | 193 kPa (28 psi) | Go to Step 7 | |||||||||||
7 |
Does the Cam Phase Angle Actual increment at all? | -- | Go to Step 8 | Go to Step 10 | ||||||||||
8 |
Does the resistance measure within the specified value? | 8-12 ohms | Go to Step 13 | Go to Step 20 | ||||||||||
9 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Does the test lamp turn ON and OFF? | -- | Go to Step 10 | Go to Step 15 | ||||||||||
10 |
Did you find a condition? | -- | Go to Step 20 | Go to Step 11 | ||||||||||
11 |
Does the spool valve move from fully closed to fully opened? | -- | Go to Step 12 | Go to Step 18 | ||||||||||
12 | Inspect for the following conditions:
Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 13 | ||||||||||
13 |
Does the resistance measure more than the specified value? | 5 ohms | Go to Step 16 | Go to Step 14 | ||||||||||
14 | Measure the resistance on the low reference circuit with a DMM. Refer to Circuit Testing . Does the resistance measure more than the specified value? | 5 ohms | Go to Step 17 | |||||||||||
15 | Test the CMP actuator high control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 19 | ||||||||||
16 | Repair the high resistance on the CMP actuator high control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 22 | -- | ||||||||||
17 | Repair the high resistance on the CMP actuator low reference circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 22 | -- | ||||||||||
18 | Test for an intermittent and for a poor connection at the CMP actuator solenoid valve assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 20 | ||||||||||
19 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 21 | ||||||||||
20 | Replace the CMP actuator solenoid. Refer to Camshaft Position Actuator Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||||
21 | Replace the PCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||||
22 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 23 | ||||||||||
23 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||||
