DTC P0343 Camshaft Position (CMP)
Sensor Circuit High Voltage
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 for the
Camshaft Position sensor tests for a loss of Camshaft Position sensor signal.
Observe that as long as
the Crankshaft Position sensor 24X signal is available, 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 incorrectly synchronized
to the exhaust stroke and will re-sync to the opposite cam position. A slightly
longer cranking time may be a symptom of this condition.
Conditions
for Running the DTC
- The ignition voltage is between
5.0 volts and 17.0 volts.
- The engine speed is less than
4,000 RPM.
Conditions
for Setting the DTC
The PCM detects the
Action
Taken When the DTC Sets
- The PCM illuminates the malfunction
indicator lamp (MIL) on the second consecutive ignition cycle that the
diagnostic runs and fails.
- The PCM records the operating
conditions at the time the diagnostic fails. The first time the diagnostic
fails, the PCM stores this information in the Failure Records. If the
diagnostic reports a failure on the second consecutive ignition cycle, the
PCM records the operating conditions at the time of the failure. The PCM
writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions
for Clearing the MIL/DTC
- The PCM turns OFF the malfunction
indicator lamp (MIL) after 3 consecutive ignition cycles that the
diagnostic runs and does not fail.
- A last test failed, or current DTC,
clears when the diagnostic runs and does not fail.
- A history DTC clears after
40 consecutive warm-up cycles, if no failures are reported by this or
any other emission related diagnostic.
- Use a scan tool in order to clear
the MIL and the DTC.
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 contaminate intrusion into the PCM.
- For any test that requires probing the PCM or a
component harness connector, use the Connector Test Adapter Kit J 35616-A .
Using this kit prevents damage to the harness connector terminals.
- The following mechanical conditions
may cause this DTC to set:
- Poor connections/terminal tension
at the sensor. Refer to Intermittents and Poor Connections Diagnosis in
Wiring Systems.
- Camshaft reluctor
wheel damage
- The sensor coming in contact with
the reluctor wheel
- Using Freeze Frame and/or Failure
Records data may aid in locating an intermittent condition. If you cannot
duplicate the DTC, the information included in the Freeze Frame and/or
Failure Records data can aid in determining how many miles since the DTC
set. The Fail Counter and Pass Counter can also aid determining how many
ignition cycles the diagnostic reported a pass and/or a fail. Operate the
vehicle within the same freeze frame conditions (RPM, load, vehicle speed,
temperature etc.) that you observed. This will isolate when the DTC
failed.
- For an intermittent, refer to Symptoms
.
The numbers below refer
to the step numbers on the diagnostic table.
- This step tests the
Camshaft Position sensor signal circuit. Applying a voltage causes the
- A duty cycle that is
present,
indicates the condition is intermittent. Inspect the jumper harness for poor
connections.
|
Step |
Action |
Value(s) |
Yes |
No |
|
Did
you perform the Powertrain On-Board Diagnostic
(OBD) System Check? |
-- |
|||
Does
the scan tool parameter increment? |
-- |
|||
Does
the scan tool indicate that this diagnostic failed this ignition? |
-- |
Go to Diagnostic Aids |
||
Does
the DMM display near the specified value? |
B+ |
|||
|
Measure
the voltage from the Camshaft Position sensor ignition feed circuit to the
Camshaft Position sensor ground circuit using the DMM J 39200 . Does
the DMM display near the specified voltage? |
B+ |
|||
Does
the |
-- |
|||
Does
the DMM display a percentage within the specified range? |
45-55% |
|||
Did
you find and correct the condition? |
-- |
Go to Diagnostic Aids |
||
Does
the DMM display near the specified voltage? |
B+ |
|||
|
Measure
the voltage from the Camshaft Position sensor ignition feed circuit to the
Camshaft Position sensor ground circuit using the DMM J 39200 . Does
the DMM display near the specified voltage? |
B+ |
|||
Is
there continuity and is the resistance within the specified range? |
0-5ohms |
|||
|
Probe
the CMP signal circuit with the DMM J 39200
connected to ground. Is the voltage less than the specified value? |
1.0V |
|||
|
Probe
the CMP signal circuit with the Test Lamp J 34142-B
connected to B+. Does the test Lamp illuminate? |
-- |
|||
Is
there continuity and is the resistance within the specified range? |
0-5ohms |
|||
|
Test
the CMP ignition feed circuit for the following:
Did
you find the condition? |
-- |
|||
Is
there continuity and is the resistance within the specified range? |
0-5ohms |
|||
Is
there continuity and is the resistance within the specified range? |
0-5ohms |
|||
Did
you find and correct the condition? |
-- |
|||
Did
you find and correct the condition? |
-- |
|||
|
Repair
the CMP ignition feed circuit for an open or a short to ground. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
Did
you find and correct the condition? |
-- |
|||
|
Repair
the CMP ground circuit for an open. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
Did
you find and correct the condition? |
-- |
|||
|
Repair
the CMP signal circuit for an open. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
|
Repair
the CMP signal circuit for a short to voltage. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
|
Repair
the CMP signal circuit for a short to ground. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
|
Repair
the CMP ignition feed circuit for:
Refer
to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
Did
you find and correct the condition? |
-- |
|||
|
Repair
the CMP ground circuit for an open. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
|
Repair
the CMP signal circuit for an open. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
Did
you find and correct the condition? |
-- |
|||
|
Replace
the Camshaft Position sensor. Refer to Camshaft
Position (CMP) Sensor Replacement . Is the action complete? |
-- |
-- |
||
Did
you find and correct the condition? |
-- |
|||
|
Important: Program the replacement
PCM. Refer to PCM
Replacement/Programming . Replace
the PCM. Is the action complete? |
-- |
-- |
||
Does
the scan tool indicate that this test ran and passed? |
-- |
|||
|
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 applicable DTC
Table |
System OK |