Fuel System - Fuel Pump Self Diagnosis DTC Information

Group:
ENGINE

Number:
2-20-009

Date
MAY, 1989

Model:
SONATA

Subject
SERVICE TIP: FUEL PUMP SELF DIAGNOSIS TROUBLE CODE INFORMATION

If the Sonata is operated with a very low fuel level, fuel pump cavitation may occur as the pump intermittently pumps liquid and vapor. The ECU can mistakenly diagnose this operating condition as a fuel pump defect, and store a fuel pump trouble code (Code 42) in its self-diagnostic memory.

When the Multi-Use Tester (MUT) is used to troubleshoot a fuel system condition, it is important to be sure that the fuel pump diagnosis is correct. When a fuel pump trouble code (Code 42) is displayed, be sure to verify that code by clearing the ECU memory and then rechecking the system.

To clear the ECU memory, remove the 20 amp ECI fuse from the engine compartment relay box for approximately 30 seconds then reinstall the fuse.

To recheck the fuel pump self diagnostic code make sure the fuel tank is at least 1/4 full, and operate the engine for approximately 5 minutes. Then use the MUT to determine if the fuel pump trouble code is still displayed. If the code is not displayed, the fuel pump is not the component requiring service.