Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see RAM VAN & RAM WAGON wiring diagram in WIRING DIAGRAMS article.
Note. DTC P0171: 1/1 FUEL SYSTEM LEAN is monitored with engine running in closed loop mode, ambient/battery temperature at more than 20°F (-6.7°C), and at altitude less than 8000 feet. DTC may be stored in Powertrain Control Module (PCM) when PCM senses fuel system is running too lean on 2 sequential trips. Possible causes are: defective Engine Coolant Temperature (ECT) sensor calibration, engine mechanical problem, fuel pressure out of specification, defective 1/1 Heated Oxygen Sensor (HO2S) heater or fuel system not switching from rich to lean.
Note. 1/1 HO2S is located in upstream position.
- Turn ignition on, with engine off. Using scan tool, read DTCs. If FUEL SYSTEM LEAN or FUEL SYSTEM RICH GOOD TRIP COUNTER is displayed and displayed count is "0", go to step 3). If FUEL SYSTEM LEAN or FUEL SYSTEM RICH GOOD TRIP COUNTER is not displayed and/or displayed count is not "0", go to next step.
- At this time, DTC P0171: 1/1 FUEL SYSTEM LEAN does not exist or is an intermittent problem. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0171: 1/1 FUEL SYSTEM LEAN returns, go to next step. If DTC P0171: 1/1 FUEL SYSTEM LEAN does not return, see «INACTIVE DTC CONDITION»(ref-139160-S32382818132002042600000) . Test is complete.
- Ensure ignition is on, with engine off. Using scan tool, read ECT sensor value. If engine coolant temperature is more than 180°F (82.2°C), allow engine coolant temperature to cool down to 150°F (65.6°C) before proceeding. If engine coolant temperature is 150°F (65.6°C) or less, start engine and monitor scan tool until engine coolant temperature reaches 180°F (82.2°C). If ECT sensor value increases smoothly, go to next step. If ECT sensor value increase is erratic, check for cooling system problems and replace ECT sensor. Perform TEST VER-5A2.
- Using scan tool, actuate 1/1 HO2S while monitoring 1/1 HO2S voltage for 2 minutes. If 1/1 HO2S voltage is more than .1 volt, replace 1/1 HO2S. Perform TEST VER-5A2. If 1/1 HO2S voltage is .1 volt or less, go to next step.
- Perform fuel pressure test. See «FUEL PRESSURE TEST»(ref-555-S29372960852000030800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - TRUCKS & RWD VANS - GASOLINE article. If fuel pressure test passes, go to next step. If fuel pressure test does not pass, repair fuel system as necessary. Perform TEST VER-5A2.
- Check the following additional items as possible mechanical problems: Engine Vacuum Must Be At Least 13" In Neutral Engine Valve Timing Must Be Within Specification Engine Compression Must Be Within Specification Engine Exhaust System Must Be Free Of Restrictions Engine PCV System Must Flow Freely Engine Drive Sprockets Must Be Properly Positioned Torque Converter Stall Speed Must Be Within Specification Power Brake Booster Must Have No Internal Leaks Fuel Must Be Free Of Contamination Fuel Injectors Must Be Free Of Restrictions Fuel Injector Control Wires Must Be Installed On Correct Injector
Repair mechanical problems as necessary. Perform TEST VER-5A2. If no mechanical problems exist, test is complete.