TWO-TRIP DETECTION LOGIC
When a malfunction initially occurs, Diagnostic Trouble Code (DTC) will be temporarily stored in ECM memory but Malfunction Indicator Light (MIL) will not illuminate. The second time malfunction is detected, MIL will illuminate provided ignition is turned off and then back on after first malfunction was detected. This is referred to as "Two-Trip Detection Logic" and only applies to specific DTCs. When road testing vehicle in CHECK mode using Toyota hand-held tester, two-trip detection logic will not function and MIL will illuminate the first time a malfunction is detected.
DATA LINK CONNECTOR
OBD-II regulations (SAE J-1962) standardizes configuration of Data Link Connector (DLC) No. 3. DLC No. 3 is located under driver's side of instrument panel. (Scheme 250)
Scheme 250
FREEZE FRAME DATA
Engine Control Module (ECM) records engine operating conditions when a misfire or fuel trim (mixture) malfunction or when various other malfunctions exist. ECM records engine operating conditions for the fuel system, calculated load, engine coolant temperature, engine speed, vehicle speed and etc. when a malfunction exists. This information is referred to as freeze frame data. If more than one Diagnostic Trouble Code (DTC) exists, only freeze frame data for the first DTC is recorded. Freeze frame data is useful for determining conditions when a malfunction occurred. OBD-II scan tool or Toyota hand-held tester may by used to read freeze frame data.
SUMMARY
If no Diagnostic Trouble Codes (DTC) are present and a no start condition exists, proceed to appropriate BASIC DIAGNOSTIC PROCEDURES article. If no DTCs are present and a driveability condition exists, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).
DTCS P0301-P0306: CYLINDERS NO. 1-6 MISFIRE DETECTED
Note. DTC P0301 is for cylinder No. 1 misfire, DTC P0302 is for cylinder No. 2 misfire, DTC P0303 is for cylinder No. 3 misfire, DTC P0304 is for cylinder No. 4 misfire, DTC P0305 is for cylinder No. 5 misfire and DTC P0306 is for cylinder No. 6 misfire. Cylinder No. 1 is front cylinder on passenger's side of engine. Cylinder No. 2 is front cylinder on driver's side of engine. Cylinders No. 1, 3 and 5 are on passenger's side of engine. Cylinders No. 2, 4 and 6 are on driver's side of engine.