Diagnostic Procedure
WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.
DIAGNOSIS PROCEDURE - P0171-FUEL SYSTEM 1/1 LEAN;
| TEST | ACTION | APPLICABILITY |
|---|---|---|
| 1 |
NOTE:
Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved silicone, oil and coolant.
NOTE:
Diagnose any Misfire DTC(s) first, if set along with the fuel system DTC. Ignition on, engine not running.With the DRBIII®, read DTCs and record the related Freeze Frame data.Is the Good Trip Counter displayed and equal to zero?Yes --> Go To 2No --> Refer to the INTERMITTENT CONDITION .Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 2 |
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Install a fuel pressure gauge.Ignition on, engine not running.With the DRBIII®, actuate the ASD Fuel System test and observe the fuel pressure gauge.
NOTE:
Fuel pressure specification is 400 kPa +/- 34 kPa (58 psi +/- 5 psi). Turn the ignition off.Choose a conclusion that best matches your fuel pressure reading.Within SpecificationGo To 3Below SpecificationGo To 12
CAUTION:
Stop All Actuations.
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| 3 |
NOTE:
If one of the O2 Sensors Signal or Return circuits are shorted to ground or voltage, all the other O2 Sensor voltage readings will be affected.
NOTE:
After the repairs have been made, verify proper O2 Sensor operation. If all the O2 Sensor voltage readings have not returned to normal, follow the diagnostic procedure for the remaining O2 Sensors. Start the engine.Allow the engine to reach normal operating temperature.With the DRBIII®, read the O2 Sensor voltage.Is the voltage switching between 2.5 and 3.4 volts?Yes --> Go To 4No --> Go To 9 |
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| 4 | Turn the ignition off.
NOTE:
Allow the O2 Sensor to cool down before continuing the test. The O2 voltage should stabilize at 5.0 volts. Raising the hood may help in reducing under hood temps. Ignition on, engine not running. With the DRBIII®, actuate the O2 Heater Test. With the DRBIII®, monitor O2 Sensor voltage for at least 2 minutes. Does the voltage stay above 4.5 volts? Yes --> Replace the O2 Sensor. Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Go To 5 |
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| 5 | Ignition on, engine not running. With the DRBIII®, read the TP Sensor voltage. While monitoring the DRBIII®, slowly open and close the throttle. Does the voltage increase and decease smoothly? Yes --> Go To 6 No --> Replace the Throttle Position Sensor. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 6 | Turn the ignition off. Connect a Vacuum Gauge to a Manifold Vacuum source. Start the engine. Allow the engine to idle.
NOTE:
If engine will not idle, maintain a constant RPM above idle. With the DRBIII® in Sensors, read the MAP Sensor vacuum value. Is the DRBIII® reading within 1" of the Vacuum Gauge reading? Yes --> Go To 7 No --> Replace the MAP Sensor. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 7 |
NOTE:
For this test to be valid, the thermostat must be operating correctly.
NOTE:
This test works best if performed on a cold engine (cold soak) Ignition on, engine not running.With the DRBIII®, read the Engine Coolant Temperature (ECT) Sensor value. If the engine was allowed to sit overnight (cold soak), the temperature value should be a sensible value that is somewhere close to the ambient temperature.
NOTE:
If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is reached. Start the Engine.During engine warm-up, monitor the ECT Sensor value. The temperature value change should be a smooth transition from start up to normal operating temperature 82°C (180°F). The value should reach at least 82°C (180°F).Did the ECT value increase with a smooth transition and did it reach at least 82°C?Yes --> Go To 8No --> Replace the Engine Coolant Temperature Sensor.Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 8 | Check for any of the following conditions/mechanical problems. AIR INDUCTION SYSTEM - must be free from leaks. ENGINE VACUUM - must be at least 13 inches in neutral ENGINE VALVE TIMING - must be within specifications ENGINE COMPRESSION - must be within specifications ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks. ENGINE PCV SYSTEM - must flow freely TORQUE CONVERTER STALL SPEED - must be within specifications POWER BRAKE BOOSTER - no internal vacuum leaks FUEL - must be free of contamination FUEL INJECTOR - plugged or restricted injector; control wire not connected to correct injector Are there any engine mechanical problems? Yes --> Repair as necessary. Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Test Complete. |
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| 9 | Ignition on, engine not running. Disconnect the O2 Sensor harness connector. With the DRBIII®, monitor the O2 Sensor voltage. The O2 Sensor voltage should read 5.0 volts on the DRBIII® with the connector disconnected. Using a jumper wire, jump the O2 Signal circuit to the O2 Return circuit at the O2 Sensor harness connector.
NOTE:
The voltage should drop from 5.0 volts to 2.5 volts with the jumper wire in place. Did the O2 Sensor volts change from 5.0 volts to 2.5 volts? Yes --> Replace the O2 Sensor Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Go To 10 |
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| 10 | Turn the ignition off. Disconnect the O2 Sensor harness connector. Ignition on, engine not running. With the DRBIII®, monitor the O2 Sensor voltage. Is the voltage above 4.8 volts? Yes --> Go To 11 No --> Check the O2 Signal circuit for a short to ground, open, or short to voltage. Inspect the O2 Sensor connector and the PCM harness connector. If OK, replace and program the Powertrain Control Module in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 11 | Turn the ignition off. Disconnect the O2 Sensor harness connector. Ignition on, engine not running. Measure the voltage on the O2 Return circuit in the O2 Sensor harness connector. Is the voltage at 2.5 volts? Yes --> Check the fuel system for contaminants. Also, check the exhaust system for any leaks. Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Check the O2 Return circuit for a short to ground, open, or short to voltage. Inspect the O2 Sensor connector and the PCM harness connector. If OK, replace and program the Powertrain Control Module in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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| 12 | Turn the ignition off.
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Raise vehicle on hoist, and disconnect the fuel pressure line at the fuel pump module. Install special 5/16 fuel line adapter tool #6539 between the disconnected fuel line and the fuel pump module. Attach a fuel pressure test gauge to the T fitting on the tool #6539 Turn the ignition on. With the DRBIII®, actuate the ASD Fuel System test and observe the fuel pressure gauge.
NOTE:
Fuel pressure specification is 400 kPa +/- 34 kPa (58 psi +/- 5 psi). Is the fuel pressure within specification? Yes --> Repair or replace fuel supply line as necessary. Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Go To 13
CAUTION:
Stop All Actuations.
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| 13 | Turn the ignition off.
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer. Is the Fuel Inlet Strainer plugged? Yes --> Replace the Fuel Pump Inlet Strainer. Perform POWERTRAIN VERIFICATION TEST VER - 5 . No --> Go To 14 |
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| 14 | If there are no possible causes remaining, view repair. Repair Replace the Fuel Pump Module. Perform POWERTRAIN VERIFICATION TEST VER - 5 . |
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