Circuit Description
The Camshaft Position sensor is mounted through the top of the engine
block at the rear of the valley cover. The CMP sensor works in conjunction
with a 1X reluctor wheel on the camshaft. The reluctor wheel is
inside the engine immediately in front of the rear cam bearing.
The PCM provides a 12 volt power supply to the CMP sensor as well
as a ground and a signal circuit.
The CMP sensor determines whether a cylinder is on a firing stroke or
on an exhaust stroke. As the camshaft rotates, the reluctor wheel interrupts
a magnetic field produced by a magnet within the sensor. The sensors
internal circuitry detects this and produces a signal which the
PCM reads. The PCM uses this 1X signal in combination with the
Crankshaft Position sensor 24X signal in order to determine crankshaft
position and stroke. This diagnostic monitors for a loss of Camshaft
Position sensor signal.
Observe that as long as the PCM receives the Crankshaft Position sensor
24X signal, the engine will start. The PCM can determine top dead center for
all cylinders by using the Crankshaft Position sensor 24X signal alone.
The Camshaft Position sensor 1X signal is used by the PCM to determine
if the cylinder at top dead center is on the firing stroke, or the exhaust
stroke. The system attempts synchronization and looks for an increase
in engine speed indicating the engine started. If the PCM does not
detect an increase in engine speed, the PCM assumes it incorrectly
synchronized to the exhaust stroke and re-syncs to the opposite
cam position. A slightly longer cranking time may be a symptom
of this condition.
Diagnostic Aids
Important
- Remove any debris from the PCM connector surfaces before servicing
the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM.
Ensure that the gaskets are installed correctly. The gaskets prevent
contaminant intrusion into the PCM.
- For any test that requires probing the PCM or component
harness connectors, use the
connector test adapter kit. Using this kit prevents
any damage to the harness connector terminals. Refer to
Using Connector Test Adapters
in Wiring Systems.
The following conditions may cause this DTC to set:
- Poor connections/terminal tension at the sensor. Refer to
Testing for Intermittent and Poor Connections
in Wiring Systems.
- Camshaft reluctor wheel damage
- The sensor coming in contact with the reluctor wheel
For an intermittent, refer to
Symptoms
.
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Powertrain On-Board Diagnostic (OBD) System
Check?
| --
|
Go to Step 2
| Go to
Powertrain On Board Diagnostic (OBD) System Check
|
2
|
- Install a scan tool.
- Idle the engine.
- Monitor the CAM signal input - High to Low transition in the Engine
Data List 1 using the scan tool.
Does the scan tool parameter increment?
| --
|
Go to Step 3
|
Go to Step 4
|
3
|
- Turn ON the ignition with the engine OFF.
- Review the Freeze Frame and/or Failure Records data for this DTC
and observe the parameters.
- Turn OFF the ignition for 15 seconds.
- Idle the engine.
- Operate the vehicle within the conditions required for this diagnostic
to run, and as close to the conditions recorded in Freeze Frame/Failure
Records as possible. Special operating conditions that you
need to meet before the PCM will run this diagnostic, where
applicable, are listed in Conditions for Setting the DTC.
- Select the Diagnostic Trouble Code (DTC) option, the Specific
DTC option, then enter the DTC number using the scan tool.
Does the scan tool indicate that this diagnostic failed this ignition?
| --
|
Go to Step 4
| Go to Diagnostic Aids
|
4
|
- Disconnect both PCM connectors. Refer to
PCM Replacement/Programming
.
- Jumper the Camshaft Position sensor ground circuit at the PCM
connector C1 (sensor side) to a known good ground.
- Jumper the Camshaft Position sensor ignition feed circuit at the
PCM connector C2 (sensor side) to B+ using a fused jumper wire. Refer to
Using Fused Jumper Wires
in Wiring
Systems.
- Measure the duty cycle from the Camshaft Position sensor signal
circuit with the
DMM.
- Crank the engine.
Does the DMM display a duty cycle within the specified range while cranking
the engine?
| 45-55%
|
Go to Step 17
|
Go to Step 5
|
5
|
- Turn OFF the ignition.
- Reconnect the PCM connectors. Refer to
PCM Replacement/Programming
.
- Remove the intake manifold in order to gain access to the Camshaft
Position sensor. Refer to
Intake Manifold Replacement
in Engine Mechanical 5.7L.
- Disconnect the Camshaft Position sensor electrical connector.
- Turn ON the ignition with the engine OFF.
- Measure the voltage from the Camshaft Position sensor B+ supply
circuit to the battery ground with the DMM.
Does the DMM display the specified voltage?
| B+
|
Go to Step
6
|
Go to Step 8
|
6
| Measure the voltage from the Camshaft Position sensor B+ supply circuit
to the Camshaft Position sensor ground circuit with the DMM.
Does the DMM display the specified voltage?
| B+
|
Go to Step
9
|
Go to Step 7
|
7
| Test for an open in the Camshaft Position sensor ground
circuit. Refer to
Testing for Continuity
in Wiring Systems.
Did you find an open ground circuit?
| --
|
Go to Step 13
|
Go to Step 17
|
8
| Test for an open or a short to ground in the Camshaft Position
sensor B+ reference circuit. Refer to
Circuit Testing
in Wiring Systems.
Did you find the circuit open or shorted to a ground?
| --
|
Go to Step 12
|
Go to Step 17
|
9
|
- Turn ON the ignition with the engine OFF.
- Measure the voltage at the Camshaft Position sensor signal circuit
to ground with the DMM.
Is the voltage less than the specified value?
| 1V
|
Go to Step
10
|
Go to Step 14
|
10
| Probe the CMP signal circuit with the test lamp
connected to battery voltage.
Does the test lamp illuminate?
| --
|
Go to Step
15
|
Go to Step 11
|
11
|
- Turn OFF the ignition.
- Disconnect the PCM connector C1 located on the same side as
the manufacturer's logo. Refer to
PCM Replacement/Programming
.
- Test the continuity of the Camshaft Position sensor signal circuit
with the DMM. Refer to
Testing for Continuity
in Wiring Systems.
Is the resistance less than the specified value?
| 2ohms
|
Go to Step 18
|
Go to Step 16
|
12
| Repair the open or short to ground
in the Camshaft Position sensor B+ reference circuit. Refer to
Wiring Repairs
in Wiring Systems.
Is the action complete?
| --
|
Go to Step
20
| --
|
13
| Repair the open
in the Camshaft Position sensor ground circuit. Refer to
Wiring Repairs
in Wiring Systems.
Is the action complete?
| --
|
Go to Step
20
| --
|
14
| Repair the short
to voltage in the Camshaft Position sensor signal circuit. Refer to
Wiring Repairs
in Wiring
Systems.
Is the action complete?
| --
|
Go to Step
20
| --
|
15
| Repair the short
to ground in the Camshaft Position sensor signal circuit. Refer to
Wiring Repairs
in Wiring Systems.
Is the action complete?
| --
|
Go to Step
20
| --
|
16
| Repair the open
in the Camshaft Position sensor signal circuit. Refer to
Wiring Repairs
in Wiring Systems.
Is the action complete?
| --
|
Go to Step
20
| --
|
17
|
- Inspect for poor connections at the PCM. Refer to
Testing for Intermittent and Poor Connections
in
Wiring Systems.
- If you find a poor connection, repair as necessary. Refer to
Repairing Connector Terminals
in
Wiring Systems.
Did you find and correct the condition?
| --
|
Go to Step 20
|
Go to Step 19
|
18
| Replace the Camshaft Position
sensor. Refer to
Camshaft Position (CMP) Sensor Replacement
.
Is the action complete?
| --
|
Go to Step
20
| --
|
19
|
ImportantProgram the replacement PCM. Refer to
PCM Replacement/Programming
.
Replace the PCM.
Is the action complete?
| --
|
Go to Step
20
| --
|
20
|
- Select the Diagnostic Trouble Code (DTC) option and the Clear
DTC Information option using the scan tool.
- Idle the engine at the normal operating temperature.
- Select the Diagnostic Trouble Code (DTC) option and the Specific
DTC option, then enter the DTC number using the scan tool.
- Operate the vehicle within the Conditions for Running the DTC
as specified in the supporting text, if applicable.
Does the scan tool indicate that this test ran and passed?
| --
|
Go to Step 21
|
Go to Step
2
|
21
| Select the Capture Info option and the Review Info option using the
scan tool.
Does the scan tool display any DTCs that you have not diagnosed?
| --
| Go to the applicable
DTC Table
| System OK
|
