"D" Check Mode
The "D" check is a special mode which can be performed by connecting a jumper. See Figure , Figure or Figure . (For the "U" check, no jumper connection is required). This mode is used in inspection by the technician at end of the assembly line. It diagnoses almost all MPFI component parts. If a fault is detected, warning light ("Check Engine" light) goes on. In either "U" or "D" check, if the warning light ("Check Engine" light) turns on due to a fault, oxygen monitor light of MPFI control unit flashes the code corresponding to the faulty part. Also, in both check modes, fail-safe function works on the same condition.
"U-Check", "Read Memory" and "D-Check" are entered by connecting and/or disconnecting the read memory and test mode connectors as required. See Fig 1 . See RELATIONSHIP BETWEEN MODES & CONNECTORS table.