The suspected circuits or parts for each problem symptom are shown in the table below. Use this table to troubleshoot when, during a DTC check, a "Normal" code is displayed but the problem is still occurring. Numbers in the table show the inspection order in which the circuits or parts should be checked.
HINT: In some cases, the problem is not detected by the diagnostic system even though a problem symptom is present. It is possible that the problem is occurring outside the detection range of the diagnostic system, or that the problem is occurring in a completely different system.

Diagnostic trouble code chart
Circuit inspectionOn-vehicle inspection
1. INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM
(a) Measure the voltage between the terminals of the ECM
connectors.
Standard:
NOTICE:
Connect test leads to the connector's backside. The connectors
should not be disconnected from the ECM.
HINT:
Voltage between the terminals of the EC ...