OXYGEN SENSOR FEEDBACK VOLTAGE TEST
- Warm engine to normal operating temperature. Connect analog voltmeter to terminals VF1 or VF2 (Non-Turbo) and E1 terminals of Data Link Connector No. 1 (DLC1). (Scheme 9) Perform test procedures listed. (Scheme 10) NOTE: On Non-Turbo, VF2 terminal is used for checking 2nd oxygen sensor.
- Depending on model application, some vehicles may be equipped with a main oxygen sensor, sub-oxygen sensor and a sensor heater. See «OXYGEN SENSOR APPLICATION»(ref-21358-S11740283702001010300000) table. NOTE: Diagnostic trouble Codes 21, 25, 26, 27 and 28 (some models) are oxygen sensor circuit codes. For diagnostic trouble code charts, see articles listed below: «TESTS W/CODES - NON-TURBO»(ref-21403) «TESTS W/CODES - TURBO»(ref-21404)
| Application Type | Main Oxygen Sensor | Sub-Oxygen Sensor | Sensor Heater |
|---|
| Non-Turbo | (1) X | (3) X | (4) X |
| Turbo | X | X | (2) X |
| (1) Two oxygen sensors required. (2) Main and sub-oxygen sensor are heated. (3) Applies to California models. (4) Heater used on main oxygen sensors and sub-oxygen sensor on California models. |
| (1) | Two oxygen sensors required. |
| (2) | Main and sub-oxygen sensor are heated. |
| (3) | Applies to California models. |
| (4) | Heater used on main oxygen sensors and sub-oxygen sensor on California models. |
OXYGEN SENSOR APPLICATION
Scheme 9
Scheme 10
EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST
Note. EGR systems contain different components and have different operating parameters depending on application. see scheme 45-50. When testing EGR system and components, use proper illustration to determine component location.
Scheme 11
Scheme 11: EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST
- Ensure EGR vacuum modulator filter(s) are clean and in good condition. Clean filter(s) with compressed air (if necessary).
- Using "T" connector, install vacuum gauge in vacuum line to EGR valve. Start engine. Ensure engine runs idles smoothly to ensure proper seating of EGR valve. NOTE: The EGR system components can be checked with engine coolant temperature less than minimum temperature and engine at specified engine RPM.
- Operate engine with engine coolant temperature less than minimum temperature and at specified RPM. See «EGR TESTING SPECIFICATIONS»(ref-21358-S23609233982001010300000) table. No vacuum reading should be obtained.
- Warm engine to normal operating temperature. Operate engine at specified engine RPM again. See «EGR TESTING SPECIFICATIONS»(ref-21358-S23609233982001010300000) table. Ensure a low vacuum reading is now obtained.
- To check EGR valve operation, remove vacuum hose from EGR valve. Using vacuum pump, apply vacuum directly to EGR valve with engine idling. Engine should run rough or stall. If EGR system does not operate as described, each individual component should be tested.
| Application | Minimum Temperature | Engine RPM |
|---|
| Non-Turbo | 113°F (45°C) | 2500 |
| Turbo | 140°F (60°C) | 3500 |
EGR TESTING SPECIFICATIONS
