DTC P1123,1127 or P0170 (With Negative Fuel Trim Number

(The PCM is decreasing fuel delivery to compensate for a "Rich" condition)

^ Check the evaporative emission system. An intermittently sticking or stuck open purge solenoid may not set an evaporative code in a 1996 or 1997 SOHO Accent or Sonata, but may set a Fuel Trim code.

^ Check the air flow sensor calibration. If no vacuum leaks are present and the purge system is functioning properly, compare the air flow sensor reading at idle and at 2500 rpm to the Air Flow Sensor Table. If readings are out of specification, swap the air flow sensor with a known good unit and re-test.

^ Check the fuel pressure (for high pressure), the fuel flow (for a return line restriction), the injector part number, the PCM part number and perform the oxygen sensor scan tool test as noted in this TSB.

Note:
For 1996 Accent SOHC with diagnostic code P1123 only, refer to TSB # 96-36-004 (Powertrain Control Module EPROM Replacement Procedure).

Note:
The table is supplied as general reference information. If the Fuel Trim conditions occur at different RPM, compare the air flow sensor reading to a known good vehicle. A "new" vehicle or sensor may read a slightly higher value than normal.