1998 GMC Savana CAM senser

What size engine? What are the symtoms? Timing injector and ignition coils are pulsed by the crank sensor, the cam sensor reads cam position so the VCM can determine which cylinder is misfiring.

It's in the distributor, test like this: TESTS W/CODES - 5.7L -1998 GMC Savana G1500
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DTC P0341 - CAMSHAFT POSITION SENSOR (CMP) CIRCUIT PERFORMANCE

NOTE: For circuit reference, see WIRING DIAGRAMS - 5.7L article.

Circuit Description
If cam/crank sensor pulse ratio is skewed, DTC will set. Fault is not a solid or consistent failure and may not act the same way twice.
Conditions for setting this DTC:
à   With engine running, CMP sensor reference pulse is not detected at correct interval.
Diagnostic Procedures
1.Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step. 2.Check for intermittent short to voltage or electromagnetic interference (i.e., wires running along side spark plug wires, high power transmitters such as mobile radios) in camshaft position sensor wires. If a problem is found, go to next step. If no problem is found, go to step 4). 3.Repair short to voltage or EMI interference as necessary. After repairs, go to next step. 4.Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2). 5.Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC is intermittent, see TESTS W/O CODES - 5.7L article.

8/4/2008

TESTS W/CODES - 5.7L -1998 GMC Savana G1500
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NOTE: For circuit reference, see WIRING DIAGRAMS - 5.7L article.

DTC P0340 - CAMSHAFT POSITION SENSOR CIRCUIT
Circuit Description
Camshaft Position (CMP) sensor is used to indicate camshaft position so that VCM can determine which cylinder is misfiring when misfire is present. Sensor also checks if high voltage switch is properly installed.
Conditions for setting DTC:
à   Engine running and camshaft position sensor reference pulse is not seen once every 2 revolutions of crankshaft.
Diagnostic Procedures
1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK, then go to next step. 2. Install scan tool. With engine idling, record FREEZE FRAME and FAILURE RECORDS for DTC. Wait one minute with engine idling. Observe LAST TEST FAILED for DTC recorded in FREEZE FRAME. If failed, turn engine off and restart. Check if Malfunction Indicator Light (MIL) is illuminated. If MIL is illuminated, go to next step. If MIL is not illuminated, go to step 8). 3. Turn ignition off. Disconnect camshaft position sensor connector. Turn ignition on, with engine off. Using test light, probe ignition feed circuit of camshaft position sensor connector (engine harness side) to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step 9). 4. Connect test light between ground circuit and ignition feed circuit of camshaft position sensor connector (engine harness side). If test light illuminates, go to next step. If test light does not illuminate, go to step 11). 5. Turn ignition off. Install Gray jumper wires from Connector Test Kit(J 35616-A) between engine harness connector and camshaft position sensor. Start engine. Using DVOM, check voltage on signal circuit. If voltage is 5-7 volts, go to step 15). If voltage is not 5-7 volts, go to next step. 6. Check for open in camshaft position sensor signal circuit. If a problem is found, go to step 13). If no problem is found, go to next step. 7. Check for short to ground in signal circuit. If a problem is found, go to step 13). If no problem is found, go to step 12). 8. DTC is intermittent. If no additional DTCs are set, see DIAGNOSTIC AIDS. If any additional DTCs are set, go to applicable DTC test. 9. Check for open in ignition feed circuit. If ignition feed circuit is open, go to step 13). If circuit is okay, go to next step. 10. Repair short to ground in ignition feed circuit. After repairs, go to step 17). 11. Repair open in ground circuit. After repairs, go to step 17). 12. Check for poor connection at camshaft position sensor. If a problem is found, go to next step. If

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TESTS W/CODES - 5.7L -1998 GMC Savana G1500
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no problem is found, go to step 14). 13. Repair circuit as necessary. After repairs, go to step 17). 14. Replace camshaft position sensor. After replacing sensor, go to step 17). 15. Check for poor connection at VCM connector. If a connection problem is found, go to step 13). If no problem is found, go to next step. 16. Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step. 17. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2). 18. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.
Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC is intermittent, see TESTS W/O CODES - 5.7L article.

8/4/2008