DELPHI EFI Sensor Signal Observation NOTE: Do not cut into or pierce sensor or engine wiring to make this connection. Sensor produces a very small signal. Corrosion or damage to wiring could lead to an incorrect signal because of repairs or contamination to sensor. 1. Using a voltmeter or diagnostic software observe voltage before engine is started. With key ON, voltage should read about 1.0 volt. This voltage is generated by ECU. If it is not present, disconnect sensor and observe voltage at harness connector. If voltage is now present, there is a short in sensor or associated wiring and corrective action should be taken.
If voltage still is not present, there is a problem with ECU or engine harness. 2. Reconnect sensor and start engine. Run engine at VXIїFLHQWVSHHGWREULQJVHQVRUXSWRRSHUDWLQJ temperature. Maintain for 1 to 2 minutes to ensure that engine has gone closed loop. Once in closed loop, sensor voltage should cycle between about 100 to 250 mv (low speed idle) and 700 to 900 mv (high speed no load). If this cycling is not observed, a determination must be made, if problem is with engine or sensor. 3. Check engine harness for battery voltage on heater circuit. Removal Inspection NOTE: Apply antiseize compound only to threads.
Antiseize compound will affect sensor performance if it gets into lower shield of sensor. 1. If sensor has heavy deposits on lower shield, engine, oil, or fuel may be source. 2. If heavy carbon deposits are observed, incorrect engine fuel control may be occurring. 3. If sensor is at room temperature, measure between signal leads, black wire (Pin C) and grey wire (Pin D) attached to sensor. If resistance is less than one megohm, sensor has an internal short. 4. With sensor at room temperature measure heater circuit resistance, purple wire (Pin A) and white wire 3LQ%UHVLVWDQFHVKRXOGEHџ 5. If a damaged sensor is found, identify root cause, which may be elsewhere in application.
Refer to TroubleshootingOxygen Sensor (O 2 ) table. 6. A special "dry to touch" antiseize compound is applied to all new oxygen sensors at factory. If recommended mounting thread sizes are used, this material provides excellent antiseize capabilities and no additional antiseize is needed. If sensor is removed from engine and reinstalled, antiseize compound should be reapplied. Use an oxygen sensor safe type antiseize compound. It should be applied according to directions on label. 33 24 690 01 Rev. D KohlerEngines.com