Diagnostic Aids

Check for any of the following conditions:

• Camshaft Position (CMP) sensor output may be affected by temperature. Check sensor operation and internal resistance at various temperatures. CMP sensor resistance when cold should be 835-1400 ohms at 14-122°F (-10 to 50°C). CMP sensor resistance when hot should be 1060-1645 ohms at 122-212°F (50-100°C).
• CMP sensor performance can be checked with a DMM and a scan tool. AC voltage output of CMP sensor, as measured with a DMM across sensor electrical terminals, is approximately the same as engine speed. Run engine at several different engine speeds and compare numerical value on scan tool with numerical voltage reading on DMM. If the reading of DMM and scan tool are not nearly equal, check for a faulty sensor or signal rotor.
• A DTC P0340 that sets while driving and checks OK may be caused by inadequate CMP sensor circuit shielding. Verify CMP sensor circuit is properly shielded and drain wire is fastened securely to ground.

An intermittent malfunction may be caused by a fault in CMP sensor electrical circuit. Check wiring harness and components for an intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 1.8L VIBE article. Repair any electrical circuit faults that were found. Information included in freeze frame data can be useful in determining vehicle operating conditions when DTC first set.