Test TC-157A - Intermittent Loss Of CMP Or CKP

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION Directory. For wiring diagram, see WIRING DIAGRAMS article.

A Camshaft Position (CMP) sensor or Crankshaft Position (CKP) sensor signal loss can be detected by an RPM change, trouble code or pattern on an oscilloscope. If this trouble code is being diagnosed with an oscilloscope, go to next step. If this trouble code is not being diagnosed with an oscilloscope, go to TEST TC-157B.
Using oscilloscope voltage lead, backprobe CMP sensor signal circuit. Start engine. Observe CMP sensor voltage pattern on oscilloscope. If any CMP sensor signals missing, go to next step. If any CMP sensor signals are not missing, go to step 5).
Turn ignition off. Disconnect CMP sensor connector. Inspect CMP sensor connector for pushed out terminals or damage. Repair CMP sensor connector as necessary. Perform TEST VER-2A. If CMP sensor is okay, go to next step.
Disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for pushed out terminals or damage. Repair PCM connector as necessary. Perform TEST VER-2A. If PCM connector is okay, replace CMP sensor. Perform TEST VER-2A.
Using oscilloscope voltage lead, backprobe CMP sensor signal circuit at Powertrain Control Module (PCM) connector terminal No. 33. See PCM TERMINALS 32 & 33 CONNECTOR WIRE IDENTIFICATION table. While observing oscilloscope pattern, wiggle wiring harness from CMP sensor connector to PCM connector. If any signals were missing when wiring harness was wiggled, repair wiring harness as necessary where wiggling caused problem to appear. Perform TEST VER-2A. If signals were not missing when wiring harness was wiggled, go to next step.
Turn ignition off. Using oscilloscope voltage lead, backprobe CKP sensor signal circuit. See CKP SENSOR CONNECTOR WIRE IDENTIFICATION table. Start engine. Observe CKP sensor voltage pattern on oscilloscope. If any CKP sensor signals are missing, go to next step. If any CMP sensor signals are not missing, go to step 9).
Turn ignition off. Disconnect CKP sensor connector. Inspect CKP sensor connector for pushed out terminals or damage. Repair CKP sensor connector as necessary. Perform TEST VER-2A. If CKP sensor is okay, go to next step.
Disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for pushed out terminals or damage. Repair PCM connector as necessary. Perform TEST VER-2A. If PCM connector is okay, replace CKP sensor. Perform TEST VER-2A.
Using oscilloscope voltage lead, backprobe CKP sensor signal circuit at PCM connector terminal 32. See PCM TERMINALS 32 & 33 CONNECTOR WIRE IDENTIFICATION table. While observing oscilloscope pattern, wiggle wiring harness from CKP sensor connector to PCM connector. If any signals were missing when wiring harness was wiggled, repair wiring harness as necessary where wiggling caused problem to appear. Perform TEST VER-2A. If signals were not missing when wiring harness was wiggled, go to next step.
Condition to set trouble code is not present at this time. INTERMITTENT LOSS OF CMP OR CKP DTC sets if expected cam signal level disagrees with actual cam signal level. Possible causes are:
- Open or shorted 8-volt supply circuit
- Open sensor ground
- Open or shorted signal circuit
- Excessive clearance between crankshaft sensor and crankshaft pulse ring
- Excessive clearance between camshaft sensor and target magnet
- Damaged target magnet
- Damaged crankshaft pulse ring
- Failed sensor
- Failed PCM.
Inspect all related wiring and connectors and repair as necessary. Perform TEST VER-2A. If no problems were found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION . Test is complete. Perform TEST VER-2A.

PCM TERMINALS 32 & 33 CONNECTOR WIRE IDENTIFICATION

Application	Wire Color
PCM Terminal No. 32 (CKP Sensor Signal Circuit)	Dark Blue/White
PCM Terminal No. 33 (CMP Sensor Signal Circuit)	Dark Blue/Red