Test TC-121A: 2/1 Fuel System Lean
NOTE:
For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.
- For 2/1 bank fuel system identification, see 2/1 BANK FUEL SYSTEM IDENTIFICATION table. Check fuel pressure. A very low fuel level could cause this trouble code to set. Ensure fuel tank is at least 1/4 full. If vehicle ran out of fuel shortly before coming in for service, erase trouble codes. Test is complete. Perform TEST VER-5A . If vehicle did not run out of fuel shortly before coming in for service, go to next step.2/1 BANK FUEL SYSTEM IDENTIFICATION
Application Location Avenger & Sebring Coupe V6 Front Bank Upstream O2S - 2/1 FUEL SYSTEM LEAN DTC sets when the Powertrain Control Module (PCM) performs a test to determine if fuel system is running too lean. If fuel system is running too lean for 2 trips, Malfunction Indicator Light (MIL) illuminates and a trouble code is stored. MIL remains on for more than one trip but goes out if conditions which occurred to set code are not found on subsequent trips. Possible causes are: faulty ignition coil, failed PCM, engine parts tolerance, leaking exhaust pipe/manifold, faulty fuel pump, plugged fuel filter, faulty secondary ignition cables, low fuel level, injectors stuck closed, faulty Manifold Absolute Pressure (MAP) sensor, faulty upstream O2S, faulty fuel pressure regulator, faulty fuel pump relay, faulty spark plugs, faulty wiring or connectors. Go to next step.
- Using scan tool, read trouble codes. If any other related trouble codes are set that can cause a lean condition, perform appropriate trouble code test. If no other related trouble codes are set that can cause a lean condition, go to next step.
- Turn engine off. Inspect cam and/or valve timing. If cam and/or valve timing are okay, go to next step. If cam and/or valve timing are not okay, repair as necessary. Perform TEST VER-5A .
- Start engine. Allow engine to idle. Run engine until normal operating temperature is reached. Check exhaust system for leaks between engine and upstream O2S. If exhaust leaks are present, repair exhaust leak as necessary. Perform TEST VER-5A . If exhaust leaks are not present, go to next step.
- Using scan tool, monitor O2S 2/1 state for 20 seconds or more. If O2S 2/1 state is not switching LEAN-CENTER-RICH twice or more in 20 seconds, go to next step. If O2S 2/1 state is switching LEAN-CENTER-RICH twice or more in 20 seconds, condition required to set trouble code is no longer present. Perform TEST VER-5A .
- Using scan tool, read long term adaptive memory value. If long term adaptive memory is between positive 20 percent and positive 32 percent, go to TEST TC-121B . If long term adaptive memory is not between positive 20 percent and positive 32 percent, condition to set trouble code is no longer present. Test is complete. Perform TEST VER-5A .