Fuel System - Fuel Mixture DTC Evaluation/Diagnosis
01 07 31Mar. 29, 2007
2010560, Supersedes Technical Bulletin Group 01 number 04-10 dated May 10, 2004 due to inclusion into ElsaWeb and update to self diagnosis functions per Base 10.01.
Vehicle Information
Condition
Evaluating Fuel Mixture DTCs - How to Perform Effective Diagnosis Related to Fuel System Adaptation - System Too Rich/Too Lean
This technical bulletin applies to fuel mixture related DTCs only (i.e. system too lean or system too rich). All other engine management DTCs should be diagnosed and eliminated before proceeding.
This technical bulletin guides the technician through a procedure to establish a "before-repair" mixture adaption baseline. You will repeat this procedure "after-repair" and compare mixture values results to determine whether the repair was successful.
Technical Background
Not applicable.
Production Solution
Not applicable.
Service
Requirements
^ Oxygen sensor control before catalyst is functioning properly. Refer to ElsaWeb or Guided Fault Finding for correct component or function check.
^ Engine operating temperature of minimum 176°F (80°C).
^ Clean vehicle snow screen, if installed.
Before-Repair Diagnosis
Part 1 - Evaluating fuel system condition at idle:
^ Connect the VAS 5051/5052 Diagnostic tool.
^ Switch ignition ON.
^ Select Vehicle Self Diagnosis".
^ Interrogate and erase fault memory.
^ Select Diagnosis Function 006 - Basic setting".
^ Input 32" on keypad to select Display group 32".
^ Select Q" button to confirm.
^ If required, Press the bottom Activating" button to initiate testing.
^ Allow motor to idle for 5 minutes.
^ Print Display group 32 values after 5 minutes.
^ This is the value used to evaluate the fuel system at idle.
Part 2 - Evaluating fuel system condition at part load:
Tip
^ Select Diagnosis Function "006 - Basic setting".
^ Input "32" on keypad to select "Display group 32".
^ Select "Q" button to confirm.
^ If required, Press the bottom "Activating" button to initiate testing.
^ Reset instrument cluster trip meter.
^ Drive vehicle for approx. 10 minutes.
^ Speed should be a minimum of 35 MPH and an appropriate gear should be selected to maintain at least 2000 RPMs.
^ After 10 minutes, the minimum distance driven should be at least 4 miles.
^ If necessary, continue driving until 4 miles are indicated on the trip meter.
^ Print Display group 32 values.
^ Before-repair" baseline is complete.
Troubleshooting tips for mixture related DTCs based on MVB 032 results
Tip:
Values in the table correspond only after performing procedures outlined in this technical bulletin. Utilized Guided Fault finding or ElsaWeb for details to the suggest checks.
Perform checks in order listed, until cause is determined.
After-Repair Diagnosis
^ Erase DTC memory to reset values to 0.
^ Repeat Part 1 - Evaluating fuel system condition at idle".
^ Repeat Part 2 - Evaluating fuel system condition at part load".
Evaluating Repair
1. Correct Display group 32 values:
^ Channel 1 = 0 +/- 10% (evaluated after Part 1 completed).
^ Channel 2 = 0 +/- 10%.
2. Required improvement values:
^ Channel 1 improvement from before-repair reading must be at least 5%.
^ Channel 2 improvement from before-repair reading must be at least 5%.
^ A repair should bring Channel 1 and Channel 2 values into correct range and improve values by the amount indicated.
Examples:
Improvement values OK. Displayed value not OK.
^ Before-repair, Channel 2 value = 16.0%.
^ After-repair, Channel 2 value = 11.0%.
^ The repair has improved the value by 5.0%, but the 11.0% displayed value is still not within the correct range of +/- 10%.
Displayed values OK. Improvement value not OK.
^ Before-repair, channel 2 value = 11.0%.
^ After-repair, channel 2 value = 8.0%.
^ The repair brought the displayed value of 8.0% into the correct range but has not achieved the required 5.0% improvement.
Displayed values OK. Improvement value also OK.
^ Before-repair, channel 2 value = 13.0%.
^ After-repair, channel 2 value = 6%.
^ The repair brought the displayed value of 6% into the correct range and has improved the value by at least 5%.
Warranty
Information only.
Required Parts and Tools
No Special Tools required.
No Special Parts required. Always see ETKA for the latest part(s) information.