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Scan tool identified faulty cam sensor, in a 96 5.2L does that refer to the pick up in the distributor or is there a seperate sensor for the cam. I know there is a crank position sensor on the engine but i have also been tricked by the scan tool identification of the code. I tried to order a cam sensor from a parts store but hey showed no listing. An engine this old if the cam sensor is the distributor pick up i would rather install a reman distributor. Anybody know which way to go?
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After replacing crank sensor Perform the crankshaft position system variation learn procedure. Refer to Crankshaft Position System Variation Learn !
No you don't need to replace the balancer !
Install a scan tool.
Monitor the powertrain control module (PCM) for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information for the applicable DTC.
Select the crankshaft position variation learn procedure with a scan tool.
The scan tool instructs you to perform the following:
4.1. Accelerate to wide open throttle (WOT).
4.2. Release the throttle when fuel cut-off occurs.
4.3. Observe the fuel cut-off specifications for the applicable engine.
4.4. The engine should not accelerate beyond the calibrated RPM value.
4.5. Release the throttle immediately if the value is exceeded.
4.6. Block the drive wheels.
4.7. Set the parking brake.
4.8. DO NOT apply the brake pedal.
4.9. Cycle the ignition from OFF to ON.
4.10. Apply and hold the brake pedal.
4.11. Start and idle the engine.
4.12. Turn the A/C OFF.
4.13. The vehicle must remain in Park or Neutral.
4.14. The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components:
• Crankshaft position (CKP) sensors activity--If there is a CKP sensor condition, refer to the applicable DTC.
• Camshaft position (CMP) signal activity--If there is a CMP signal condition, refer to the applicable DTC.
• Engine coolant temperature (ECT)--If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.
Enable the crankshaft position system variation learn procedure with the scan tool and perform the following:
Important: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete.
5.1. Accelerate to WOT.
5.2. Release when fuel cut-off occurs.
5.3. Test in progress.
The scan tool displays Learn Status: Learned this ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to DTC P0315. If any other DTCs set, refer to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information for the applicable DTC.
Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.
The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set.
• Engine replacement
<p><b><span>3.2) <span> </span><u>CMP - Cam
shaft Position </u>(sensor)<u> </u></span></b><br />
<p><b><u><br /></u></b><br />
<p><b><span>What is it?</span></b><span><span>
</span>This electrical device is very similar in concept to the crank position
sensor (above) in that it detects the position of the rotation of a shaft, in
this instance the cam shaft.<span> </span>It is the
cam shaft signal that indicates to the ECU that cylinder one is at top dead
centre at compression and in the process provides the ECU with the timing reference
for fuel injection.<span> </span>The cam shaft sensor
provides extra information, to that of the crank sensor, to fine tune timed
events such as injection and spark delivery.</span><br />
<p><span> </span><br />
<p><b><span>Where is it located?</span></b><span> The location of this
device depends on the design and age of engine.<span>
</span>On many modern overhead cam shaft engines the cam shaft sensor is
located either on the end, or to the side of the end, of the cam shaft housing.<span> </span>On older pushrod engines the cam sensor is found
where the distributor would once have been located.<span> </span>This type sensor assembly makes use of the
distributor shaft meshing directly, at its bottom end, with a gear on the cam
within the engine block.<span> </span>In this respect
the distributor shaft is just an extension of the cam shaft.<span> </span>On the top end of this distributor shaft is a
magnetic armature.<span> </span>The cam shaft sensor,
that measures the movement of this armature, is located in the cover and uses
either magnetic or 'Hall effect' pickup modules.<span> </span></span><br />
<p><b><span> </span></b><br />
<p><b><span>How does it work?</span></b><span><span> </span>The sensor detects the position of a magnet
or set of teeth on the gear on the end of the cam.<span> </span>An electrical waveform output signal is sent
to the ECU as the cam turns.<span> </span>The cam
sensor tells the ECU that cylinder 1 is at TDC on its compression stroke prior
to ignition. <span> </span>The cam sensor ensures the
correct timing of the fuel injection cycle.<span>
</span>If the timing belt ever jumps a tooth on the cam the lack of agreement between
the respective signals from the cam and crank sensors is indicated as an error condition
by the ECU. </span><br />
<p><b><u><span><span> </span></span></u></b><br />
<p><b><u><span>Symptoms of faulty cam sensor</span></u></b><br />
<p><b><span>Associated OBD2 error codes DTCs: <span> </span>P0341 - P0349; P1345</span></b><br />
<p><b><span> </span></b><br />
<ul>
<li><b><span>Hesitant acceleration - </span></b><span>miss-timing
of fuel injection due to a faulty CMP can cause intermittent loss of power.<b></b></span></li>
<li><b><span>Starting
difficulty/failure.<span> </span></span></b><span>If the
faulty CMP timing problems are severe they may cause the engine not fire
at all, or to fire and then stall, or stall at some random time without
warning.<b></b></span></li>
<li><b><span>Hot engine stall and failure to
restart - </span></b><span>Sometimes the fault of the CSS only manifests
itself when the engine is hot.<span> </span>Over
time thermal stress can cause cracking and can weaken electrical junctions
within the CMP.<span> </span>The CMP may work
well at cold start up but can then cause a hot running engine to stop with
little chance of restart whilst the engine is still hot;<span> </span>once cooled the down the engine may
readily restart and again run for a limited period until hot.</span></li></ul>
<p><b><u><span>Note </span></u></b><span>The cam sensor body often
protrudes into the cam shaft gallery and when it's 'o' ring seal<span> </span>becomes age hardened, engine oil may leak
back into the sensor electrical socket plug connector causing errors due to
interruption of signal. </span><br />
<p><b><span> </span></b><br />
<p><b><span>How to check? </span></b><span>It is not technically<b> </b>easy<b>
</b>to determine that the CMP is at fault and, like the crank sensor, may
require the use of an oscilloscope.<span> </span>If
it is part of a sophisticated on board diagnostics system its failure may be
logged as a specific error code in the ECU. Due to the variability problems
with engine running are often experienced well before any error codes are set
by the ECU.</span><br />
<p><span> </span><br />
<p><span><span> </span>2
pin socket (magnetic - sine wave output).<span>
</span>One pin is 'ground' the other is 'signal'.<span> </span>A voltmeter set to 2 volts AC should measure
a signal in the 0.2 to 2 volts range on the 'signal' pin.</span><br />
<p><span><span> </span>3
pin socket (Hall effect, magneto - square wave form output).<span> </span>One pin is 'reference' (5volts), one pin is
'ground' and the third pin is 'signal'.<span>
</span>A DC voltage should be detectable in the 0.5 to 1.5 volt range from the
'signal' pin.</span><br />
<p><span>It is important that
the voltage measurement take place at start up when the engine is cold and
again, 20 minutes later, when the engine has fully warmed up to operating
temperature. Often the voltage output from faulty sensors declines with
temperature rise.</span><br />
<p><span> </span><br />
<p><b><span>How to fix?<span>
</span></span></b><span>If the CMP failure is due oil leakage into the
electrical connector then a thorough clean and a renewal of the oil seal on the
CMP may correct the situation.<span> </span>It can be
a wise precaution to change the connecting cable as oil migration beneath the
insulation may possibly contaminate components at some distance to the CMP.<span> </span></span><br />
<p><span>If the CMP has an
internal fault then it must be replaced.</span><br />
Have the crank sensor checked, some times a generic scan tool or code reader will pull a code but list cam sensor and then when code is read with a gm tool it reads crank sensor, can you give me the code #? you may also have a wiring problem to cam sensor or faulty ecm or bcm. ( computer) engine control module) good day but still have the crank tested ,good day
The 4 cyl and 6 cyl engines use a distributor, so no crank and cam sensors. There is a pick-up coil in the bottom of the distributor that could be failing. Code 12 means the battery has been disconnected or the ECM has lost power since the last scan.
Stip by any good parts store (Autozone, Advance, etc..) and have an OBII scan done - they do this free. It will identify all faults that computer has tracked and will identify what is causing running issues.
OBD Code 12 - No Distributor Reference Pulse (Diagnostic Test Active)
The Engine Control Module-ECM uses the distributor reference pulse to calculate the engine speed. On
newer engines, the Crank Shaft Position Sensor performs this function.
Symptoms:
When flashing the Check Engine Light to read codes, code 12 will always display first, indicating the diagnostic system is active
The engine will not run with a "hard" code 12 set
Common Problems:
Chances are you will never need to diagnose a code 12. Rather, the problem would be a crank, no-start condition.
If code 12 does not flash, that would indicate a communication problem with the ECM.
Code 12 does not show when reading codes with a scan tool. If there
is a communication problem, the scan tool will let you know.
OBD Code 46 - Pass-Key II System Error - Circuit out of Frequency Range
The ECM receives a signal from the Pass-Key module. When the correct signal is
received, the ECM will allow the engine to start and run. Please review
the RepairPal article on the GM Pass-Key Anti-theft systems for more information.
Symptoms:
Engine may not start
Common Problems:
Faulty ignition lock cylinder
OBD Code 43 - Knock Sensor error
The ECM receives a signal from the Knock Sensor based on the amount of engine ping detected. The ECM uses information from this sensor to help calculate fuel delivery and spark timing.
What all did the
mechanic check ? Just codes . Did the mechanic check engine sensor data paramitors ?
Checks
Action
DEFINITION: The engine runs unevenly during idle. If the condition is severe, the engine or the vehicle may shake. The engine idle speed may vary in RPM. Either condition can be severe enough to stall the engine.
Preliminary Check
Refer to Symptoms - Engine Controls .
Sensor Checks
• Check the heated oxygen sensor (HO2S).
Check for silicon contamination from fuel or from an improperly-used sealant. The sensor will have a white powdery coating. The sensor will produce a high but false signal voltage, or indicate a rich exhaust. The control module will reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
• Check the throttle position (TP) sensor. If a sticking throttle shaft or binding linkage causes a high TP sensor open throttle indication, the control module will not control the idle. Monitor the TP sensor voltage. A scan tool or voltmeter should read less than 0.85 volts with the throttle closed.
• Check the engine coolant temperature (ECT) sensor using the scan tool in order to compare the engine coolant temperature with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5 degrees more than or less than the ambient air temperature on a cold engine, check for a high resistance in the coolant sensor circuit or the sensor itself.
• Check the manifold absolute pressure (MAP) sensor response and accuracy.
Fuel System Checks
• Check the fuel pressure. Refer to Fuel System Diagnosis .
• Check to determine if a rich or lean system causes the condition. Drive the vehicle at the speed of the complaint. Monitoring the fuel trim will help to identify the problem.
- Lean--The long term fuel trim is more than 150.
- Rich--The long term fuel trim is less than 115.
• Perform the fuel injector balance test. Refer to Fuel Injector Balance Test with Tech 2 .
• Check the fuel injector driver circuit.
1. Disconnect the injector harness connector at the injectors.
2. Connect an injector test lamp between the terminals of each injector connector and note the lamp while cranking.
3. If the test lamp fails to blink at any connector, the test lamp has a faulty injector drive circuit harness, connector, or terminal.
• Perform the fuel injector coil test. Refer to Fuel Injector Solenoid Coil Test .
• Check the evaporative emission (EVAP) control system.
Ignition System Checks
• Check the ignition output using the J 26792 Spark Tester or the equivalent. Refer to Distributor Ignition (DI) System Diagnosis .
• Check for the following conditions:
- Wet plugs
- Cracks
- Wear
- Improper gap
- Burned electrodes
- Blistered insulators
- Heavy deposits
• Check the spark plug wires by connecting a DMM to the ends of each wire in question. If the meter reads over 30,000 ohms, then replace the wires.
Additional Checks
• Check for vacuum leaks. Vacuum leaks can cause a higher than normal idle and low idle air control (IAC) counts.
• Check the IAC operation. Refer to Idle Air Control (IAC) System Diagnosis .
• Check the control module grounds for being clean, tight, and in their proper locations.
• Check the scan tool to determine if the control module is receiving an A/C signal. If a problem exists with the A/C ON, check the A/C system operation.
• Check for the exhaust gas recirculation (EGR) being ON while idling which will cause roughness, stalling, and hard starting.
• Check the battery cables and ground straps. The cables and straps should be clean and secure.
• Check the crankcase ventilation valve for proper operation by placing a finger over the inlet hole in the valve end several times. The valve should snap back. If the valve does not snap back, replace the valve.
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