* PLEASE READ FIRST *
If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed with self-diagnostics. If no Diagnostic Trouble Codes (DTCs) are present after entering self-diagnostics, proceed to H - TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).
TWO-TRIP DETECTION LOGIC
When a malfunction initially occurs, Diagnostic Trouble Code (DTC) will be temporarily stored in ECM memory, but MIL on instrument panel will not illuminate. The second time malfunction is detected, MIL on instrument panel will illuminate, provided ignition is turned off and then back on after first malfunction was detected. This is referred to as the 2-Trip Detection Logic and only applies to specific DTCs.
Note. When road testing vehicle in CHECK mode (Toyota scan tool only), the Two Trip Detection Logic will not function. Also, MIL will illuminate first time a malfunction is detected.
DATA LINK CONNECTOR
OBD-II regulations (SAE J-1850) standardizes Data Link Connector (DLC) configurations. See DATA LINK CONNECTOR (DLC) NO . 3 LOCATION table. See 1 in TESTS W/CODES article.
| Application | Location |
|---|---|
| Avalon, Corolla, Supra & Tercel | Left Side Of Instrument Panel, Left Of Steering Column |
| Camry, Celica, RAV4 & Sienna | Left Side Of Instrument Panel, Right Of Steering Column |
| Land Cruiser & LX470 | Left Side Of Instrument Panel, Left Of Steering Column |
| Tacoma, T100 & 4Runner | Left Side Of Instrument Panel, Right Of Steering Column |
DATA LINK CONNECTOR (DLC) NO. 3 LOCATION
FREEZE-FRAME DATA
OBD-II or Toyota scan tool can by used to check freeze-frame data. The ECM records engine operating condition when a misfire, fuel trim (mixture) malfunction or other malfunction (fuel system, calculated load, coolant temperature, fuel trim (mixture), engine speed, vehicle speed, etc.) exists. If more than one fault is detected, only data from the first malfunction is recorded. Recorded data is useful for determining conditions in which the malfunction occurs.
NORMAL Mode Code Retrieval
- Connect scan tool to Data Link Connector (DLC) No. 3. See 1 in TESTS W/CODES article. Turn ignition on with engine off. Turn scan tool on. Using scan tool manufacturer's instructions, check for DTCs and freeze-frame data.
- If scan tool displays UNABLE TO CONNECT TO VEHICLE, DLC No. 3 must be checked. See «DLC NO»(ref-22529-S06849565722001010300000) . 3 INSPECTION under SCAN TOOL PROBLEMS. If scan tool does not display UNABLE TO CONNECT TO VEHICLE, go to next step.
- Record any DTCs and freeze-frame data displayed for system diagnosis. If driveability problem exists and no DTCs are present, go to TESTS W/O CODES article for diagnosis by symptom.
- If any DTCs are present, perform appropriate DTC test under DIAGNOSTIC TESTS in TESTS W/CODES article. See «DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION»(ref-22529-S24824537672001010300000) table. For more information on freeze-frame data, see «FREEZE-FRAME DATA»(ref-22529-S15756276732001010300000) under INTRODUCTION. For information on 2-trip detection logic codes, see «TWO-TRIP DETECTION LOGIC»(ref-22529-S16672783712001010300000) under INTRODUCTION.
- After repairs for DTC have been completed, DTCs must be cleared from ECM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-22529-S33571829712001010300000) . Road test vehicle to ensure all symptoms and/or complaints have been repaired.
Supra Turbo
- Manufacturer recommends using Check Harness "A" (SST 09990-01000) when using DTC tests to diagnose malfunctions. Check harness "A" is a test harness that is installed between Electronic Control Module (ECM) and ECM connectors. (Scheme 37) Voltage and resistance readings are taken at check harness connectors. NOTE: Always check and note diagnostic trouble codes prior to disconnecting ECM connector. Disconnecting ECM connector will erase codes from memory.
- To install check harness "A", ensure ignition switch is in the OFF position. Disconnect ECM connector. See «ECM LOCATION»(ref-22529-S05611535612001010300000).
- Connect check harness "A" between ECM and ECM connectors. Terminal arrangement of check connector is the same as those on the ECM. Wire colors that are specified in procedures apply to ECM connectors, but may not apply to check harness connectors. Proceed to appropriate DTC test under DIAGNOSTIC TESTS in TESTS W/CODES article.
Scheme 37
SUMMARY
If no diagnostic trouble codes are present, driveability symptoms exist or intermittents exist, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent procedures.