DTC 0342

[Eglide98]

I have a 02 Sierra 2500HD with an 8.1L. It's throwing 0342 code still after changing the cam position sensor and the connector to the ECM. All DTCs were erased after the replacement but keep coming back. Any technical help would be appreciated

[xwire]

Have you checked the crank sensor? On my 01 a faulty crank sensor was throwing a cam code as well as sporadic dieing and hard to start

[gmtech4]

get the proper dtc diag chart and follow it ,,,if ya want it ,let me know

[Eglide98]

I'm don't want to start throwing $ away

replacing parts. The chart would be helpful.

[gmtech4]

DTC P0342

Circuit Description

The camshaft position (CMP) sensor works in conjunction with a 1X reluctor
wheel on the camshaft. The powertrain control module (PCM) provides a 12–volt
reference circuit to the CMP sensor as well as a low reference 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 CKP sensor 24X signal in order to
determine CKP and stroke. This diagnostic for the CMP sensor checks for a loss
of CMP sensor signal.

Observe that as long as the PCM receives the CKP sensor 24X signal, the
engine will start. The PCM can determine top dead center (TDC) for all cylinders
by using the CKP sensor 24X signal alone. The CMP sensor 1X signal is used by
the PCM in order to determine if the cylinder at TDC is on the firing stroke or
on 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 the engine speed 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.

Conditions for Running the
DTC

The engine speed is less than 4,000 RPM.

Conditions for Setting the
DTC

The PCM detects the cam signal is stuck low when the signal should be high
for 1.5 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 following conditions may cause this DTC to set:

• Camshaft reluctor wheel damage
• 
  
• The sensor coming in contact with the reluctor wheel
• 
  
• Foreign material passing between the sensor and the reluctor wheel

Using Freeze Frame/Failure Records data may aid in locating an intermittent
condition. If you cannot duplicate the DTC, the information included in the
Freeze Frame/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 or a fail. Operate the vehicle
within the same Freeze Frame conditions such as RPM, load, vehicle speed,
temperature, etc. that you observed. This will isolate when the DTC failed.

The CMP sensor output can be tested. The sensor must be supplied with a power
and a ground. The engine must be cranking to perform this test. You can measure
the duty cycle at the signal circuit of the sensor. The duty cycle should be
between 45–55 percent for a good sensor. An internally shorted CAM sensor can
pull the 12-volt reference circuit low causing DTC P0335 to set.

If the problem is intermittent, refer to Intermittent
Conditions.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. • This step verifies that the fault is present. A hard start is
     observed when a malfunction is present.
   
   
   • This step tests the CMP sensor 12–volt reference circuit from the
     PCM to the CMP.
   
   
   • This step tests the CMP sensor low reference circuit from the PCM to
     the CMP.
   
   
   • This step tests the CMP sensor signal circuit. Applying a voltage
     causes the CAM signal input - high to low and low to high parameter to increase
     if the circuit and the PCM are operating properly.
   
   
   • This step tests the resistance of the CMP sensor 12–volt reference
     circuit from the PCM to the CMP sensor.
   
   
   • This step tests the resistance of the CMP sensor low reference
     circuit from the PCM to the CMP sensor.

DTC P0342

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls
Schematics

1

Did you perform the Diagnostic System Check–Engine Controls?

—

Go to Step 2

Go to Diagnostic
System Check - Engine Controls

2

2. Install a scan tool.
3. 
   
4. Start the engine.
5. 
   
6. Monitor the CAM signal input high to low and low to high
   transition parameter using the scan tool.

Does the scan tool parameter increment?

—

Go to Step 3

Go to Step 4

3

2. Observe the Freeze Frame/Failure Records data for this DTC.
3. 
   
4. Turn OFF the ignition for 30 seconds.
5. 
   
6. Start the engine.
7. 
   
8. Operate the vehicle within the Conditions for Running the
   DTC as specified in the supporting text or as close to the Freeze Frame/Failure
   Records data that you observed.

Does the DTC reset?

—

Go to Step 4

Go to Diagnostic Aids

4

2. Turn OFF the ignition.
3. 
   
4. Disconnect the CMP sensor. Refer to Camshaft
   Position Sensor Replacement.
5. 
   
6. Turn ON the ignition, with the engine OFF.
7. 
   
8. Measure the voltage on the CMP sensor 12-volt reference
   circuit using the DMM connected to battery ground.

Does the voltage measure near the specified value?

B+

Go to Step 5

Go to Step 7

5

Measure the voltage from the CMP sensor 12-volt reference circuit to the CMP
sensor low reference circuit using the DMM.

Does the voltage measure near the specified voltage?

B+

Go to Step 6

Go to Step 9

6

2. Start the engine.
3. 
   
4. Monitor the CAM signal input high to low and low to high
   transition using the scan tool.
5. 
   
6. Momentarily and repeatedly probe the signal circuit with the
   test lamp connected to B+.

Does the CAM signal input high to low and low to high transition counters
increment when the test lamp contacts the signal circuit?

—

Go to Step 15

Go to Step 10

7

2. Turn OFF the ignition.
3. 
   
4. Disconnect the PCM connector C2 located on the opposite side
   of the manufacturers logo. Refer to Powertrain
   Control Module Replacement.
5. 
   
6. Test the resistance of the CMP sensor 12-volt reference
   circuit using the DMM.

Does the resistance measure within the specified range?

0–5 Ω

Go to Step 8

Go to Step 12

8

Inspect the CMP 12-volt reference circuit for the following:

• A grounded circuit
• 
  
• A poor connection

Did you find and correct the condition?

—

Go to Step 19

Go to Step 16

9

2. Turn OFF the ignition.
3. 
   
4. Disconnect the PCM connector C1, located on the same side as
   the manufacturer's logo. Refer to Powertrain
   Control Module Replacement.
5. 
   
6. Test the resistance of the CMP low reference circuit using
   the DMM.

Does the resistance measure within the specified range?

0–5 Ω

Go to Step 16

Go to Step 13

10

2. Turn OFF the ignition.
3. 
   
4. Disconnect the PCM connector C1 located on the same side as
   the manufactures logo. Refer to Powertrain
   Control Module Replacement.
5. 
   
6. Test the resistance of the CMP signal circuit using the DMM.

Does the resistance measure within the specified range?

0–5 Ω

Go to Step 11

Go to Step 14

11

2. Turn ON the ignition, with the engine OFF.
3. 
   
4. Test the CMP signal circuit for the following:
   • A grounded circuit
   • 
     
   • A circuit shorted to a voltage

Did you find and correct the condition?

—

Go to Step 19

Go to Step 16

12

2. Inspect the CMP sensor 12-volt reference circuit for an
   open.
3. 
   
4. If you find an open circuit , repair the CMP sensor 12-volt
   reference circuit. Refer to Wiring
   Repairs in Wiring Systems.

Did you find and correct the condition?

—

Go to Step 19

Go to Step 16

13

Repair the CMP low reference circuit for an open. Refer to Wiring
Repairs in Wiring Systems.

Did you complete the repair?

—

Go to Step 19

—

14

Repair the CMP signal circuit for an open. Refer to Wiring
Repairs in Wiring Systems.

Did you complete the repair?

—

Go to Step 19

—

15

2. Inspect for poor connections at the CMP harness connector.
   Refer to Testing for
   Intermittent Conditions and Poor Connections in Wiring Systems.
3. 
   
4. If you find a poor connection, repair the connector as
   necessary. Refer to Connector
   Repairs in Wiring Systems.

Did you find and correct the condition?

—

Go to Step 19

Go to Step 17

16

2. Inspect the PCM harness connector for poor connections.
   Refer to Testing for
   Intermittent Conditions and Poor Connections in Wiring Systems.
3. 
   
4. If you find a poor connection, repair the connector as
   necessary. Refer to Connector
   Repairs in Wiring Systems.

Did you find and correct the condition?

—

Go to Step 19

Go to Step 18

17

Replace the CMP sensor. Refer to Camshaft
Position Sensor Replacement.

Did you complete the replacement?

—

Go to Step 19

—

18

Replace the PCM. Refer to Powertrain
Control Module Replacement.

Did you complete the replacement?

—

Go to Step 19

—

19

2. Use the scan tool in order to clear the DTCs.
3. 
   
4. Turn OFF the ignition for 30 seconds.
5. 
   
6. Start the engine.
7. 
   
8. Operate the vehicle within the Conditions for Running the
   DTC as specified in the supporting text.

Does the DTC run and pass?

—

Go to Step 20

Go to Step 2

20

With a scan tool, review the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

[xwire]

But seeing as the cam sensor uses the crank sensor for reference if there is a problem with the crank sensor you will possibly show a cam sensor code

 

Garbage in = garbage out.....

 

And heavens knows these trucks had a problem with the crank sensors being a little long and coming into contact with the flywheel early on....

 

Coming from a diagnostic master tech not a parts chaser. I was simply stating don't rule out testing the crank sensor as it could give you a false cam sensor code

[Eglide98]

Between the location and breakage horror stories. Is there a removal technique that can prevent breakage

[xwire]

I have been able to come from below, reaching up above by the firewall and after moving the harness to the side been able to slide the old one out for testing. Usually ones that have made contact you can see the groove on them at the tip.

[Eglide98]

Have you had any break ? If so, how would you get it out ?

[xwire]

I've been lucky not to break any I just make sure to move the harness/hoses above it to allow it to come straight out the top... It is a long sucker for sure but if you keep from twisting it it should come out no problem

[Eglide98]

I'm going to have a diagnostic test 1st before making any decisions. Thanks for your help