Test TC-104A: 1/2 O2 Sensor Slow Response
NOTE:
For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see WIRING DIAGRAMS article.
NOTE:
On BE/BR bodies with 8.0L medium-duty engine, 1/2 Heated Oxygen Sensor (HO2S) is located in pre-catalyst position. On all other bodies, 1/2 HO2S is located in downstream position. On models equipped with 4 HO2S, 1/2 HO2S is located in left downstream position.
- Start engine. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If exhaust system is okay, go to next step.
- Check exhaust for excessive smoke caused by oil or coolant consumption. Repair engine mechanical condition as necessary, replace catalytic converter and HO2Ss, and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If engine mechanical condition is okay, go to next step.
- Turn ignition off. Disconnect 1/2 HO2S connector. Inspect connector and terminals for damage. Repair connector and terminals as necessary and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If connector and terminals are okay, go to next step.
- Using an external ohmmeter, check resistance between ground and 1/2 HO2S connector), sensor ground circuit (Brown/Yellow wire on TJ body; Black/Light Blue wire on all other bodies). If resistance is 5 ohms or more, repair open sensor ground circuit and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If resistance is less than 5 ohms, go to next step.
- Disconnect Powertrain Control Module (PCM) connectors. Inspect connectors and terminals for damage. Repair connectors and terminals as necessary and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If connectors and terminals are okay, replace 1/2 HO2S and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES .