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. |
| • | The driver has the ability to detect an electrical malfunction in the ignition positive or ground circuit. If an electrical malfunction occurs, the driver signals the PCM to set this diagnostic trouble code (DTC). |
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The PCM detects an electrical malfunction in the camshaft position actuator solenoid high control or low reference circuits. |
| • | The condition is present for more than 0.25 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. |
The PCM disables the Cam phaser for the ignition cycle.
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 camshaft 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 camshaft actuation system 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 for 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 |
| - | Debris or contamination interfering with the camshaft position actuator solenoid valve assembly |
| • | Engine oil has a major impact upon the camshaft actuation system's responsiveness. Oil temperature, pressure, viscosity, and quality can slow and/or inhibit the actuator systems ability to reach a desired phase angle. |
| • | An intermittent may be caused by any of the following conditions: |
| • | A poor connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
| • | Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Repair the circuits as necessary. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Does the engine run rough or stall? | -- | Go to Step 3 | Go to Step 4 |
3 |
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 |
Does the DMM display voltage at the specified value? | B+ | Go to Step 5 | Go to Step 7 |
5 | Connect a test lamp between the camshaft position actuator solenoid high control circuit and ground. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 6 |
6 | Connect a test lamp between the low reference circuit and B+. Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 8 |
7 | Test the camshaft position actuator solenoid high control circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
8 | Test the low reference circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
9 | Test the camshaft position actuator solenoid high control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 |
10 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 |
11 | Inspect for poor connections at the harness connector of the camshaft position actuator solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 |
12 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
13 | Replace the camshaft position actuator solenoid. Refer to Camshaft Position Actuator Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
14 |
Does the DTC run and pass? | -- | Go to Step 15 | Go to Step 2 |
15 | Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
