Fuel System - MIL ON/DTC's P0170/P0171 Set

Group: FUEL SYSTEM

Number: 09-FL-005

Date: MARCH, 2009

Model:
2008 - 2009MY HD ELANTRA

Subject:
MIL ON WITH DTC P0170 OR P0171 DIAGNOSTIC PROCEDURE

DESCRIPTION:

If a 2008-2009 model year Elantra (HD) vehicle illuminates the Malfunction Indicator Lamp (MIL) with DTC P0170 or P0171:

P0170: Fuel Trim Bank 1

P0171: System Too Lean Bank 1

^ Verify that the fuel pump replacement Campaign 086 has been completed for applicable vehicles as shown below.

^ Perform the service procedures described below. Do not perform Air flow sensor or Oxygen sensor inspection and replacement. The causal part for these DTC's may be the fuel pump, not Air flow sensor or Oxygen sensor.





APPLICABLE VEHICLES

SERVICE PROCEDURE:

1. Verify that the vehicle is in the affected range by VIN and production date period.

2. If the vehicle is affected, confirm whether the fuel pump replacement Campaign 086 service has been performed.

3. If not, first conduct the campaign service following TSB 08-01-011-1. Verify vehicle has open Campaign 086 via WEBDCS.

4. After completing the campaign service, erase all DTC's using a GDS, and inspect to be sure that no DTC returned.

5. Confirm fuel trims are normal; they should remain within +/- 10%.

NOTE:
When the previous conditions are met there is no need to replace any additional parts, such as an Airflow Meter or the Linear Oxygen Sensor.

WARNING:
DO NOT REPLACE A LINEAR OXYGEN SENSOR IN A HD VEHICLE BECAUSE IT HAS A FLATLINE OUTPUT.

^ The Linear Oxygen Sensor does not switch like a conventional switching Oxygen Sensor because it has an output linear to the air fuel ratio.

^ Most of the time, such as during idle and cruise operation, its output will appear to be flatline because the air fuel ratio changes very little during driving, as the system is tightly controlling the air fuel ratio.





Normal Linear Oxygen Sensor response at idle or cruise:

^ The Linear Oxygen sensor will only show significant change during transients such as accelerations and decelerations when the air fuel ratio can significantly change.





Normal Linear Oxygen Sensor output during accelerations/decelerations:

WARRANTY INFORMATION:

Normal warranty applies.