DATA LINK CONNECTOR
OBD-II regulations standardize Data Link Connector (DLC) configurations. DLC No. 3 connector is located under left side of instrument panel. (Scheme 35)
Scheme 35
FREEZE-FRAME DATA
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 first malfunction is recorded. Recorded data is useful for determining conditions in which malfunction occurs.
Hard Failures
Hard failures cause Malfunction Indicator Light (MIL) to illuminate and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic (code) charts. If a sensor fails, ECM will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, the vehicle runs but driveability will not be optimum.
Intermittent Failures
Intermittent failures may cause Malfunction Indicator Light (MIL) to flicker or illuminate and go out after the intermittent fault goes away. However, the corresponding trouble code will be retained in ECM memory. If related fault does not reoccur within a certain time frame, related trouble code will be erased from ECM memory. Intermittent failures may be caused by a sensor, connector or wiring related problems. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
NORMAL Mode Code Retrieval
- Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 35) DLC No. 3 is located under left side of instrument panel. 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. 3 INSPECTION»(ref-151781-S19086168262003010800000) 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 «TROUBLE SHOOTING - NO CODES»(ref-151782) article for diagnosis by symptom.
- If any DTCs are present, perform appropriate diagnostic test in «DIAGNOSTIC TESTS»(ref-151781-S38241362492003010800000). See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151781-S14237703072003010800000) table. For more information on freeze-frame data, see «FREEZE-FRAME DATA»(ref-151781-S33978050772003010800000) under INTRODUCTION. For information on 2-trip detection logic codes, see «TWO-TRIP DETECTION LOGIC»(ref-151781-S40978373742003010800000) under DETECTION LOGIC under INTRODUCTION.
- After repairs for DTC have been completed, DTCs must be cleared from ECM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151781-S26653383402003010800000).
SUMMARY
If no diagnostic trouble codes are present, but driveability symptoms or intermittent problems exist, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent procedures.
Confirmation Driving Pattern
Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 35) If using Lexus scan tool, switch to CHECK mode. On both scan tools, start and warm engine to normal operating temperature. Allow engine to idle for 100 seconds or more. Drive vehicle at 24 MPH or more for 20 seconds. Stop vehicle and allow to idle for 20 seconds. Repeat driving and idle part of test 2 more times. (Scheme 36) At last idle test, allow to idle for 30 seconds. If using OBD-II scan tool, turn engine off. Repeat this procedure. If using either scan tool, if malfunction exists, MIL will illuminate.
Scheme 36
Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 35) If using Lexus scan tool, switch to CHECK mode. On both scan tools, start and warm engine to normal operating temperature. Allow engine to idle for 100 seconds or more. Drive vehicle at 24 MPH or more for 20 seconds. Stop vehicle and allow to idle for 20 seconds. Repeat driving and idle part of test 2 more times. At last idle test, allow to idle for 30 seconds. (Scheme 36) If using OBD-II scan tool, turn engine off. Repeat this procedure. If using either scan tool, if malfunction exists, MIL will illuminate.
Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 35) If using Lexus scan tool, switch to CHECK mode. On both scan tools, start and warm engine to normal operating temperature. Allow engine to idle for 100 seconds or more. Drive vehicle at 24 MPH or more for 20 seconds. Stop vehicle and allow to idle for 20 seconds. Repeat driving and idle part of test 2 more times. At last idle test, allow to idle for 30 seconds. If using OBD-II scan tool, turn engine off. Repeat this procedure. If using either scan tool, if malfunction exists, MIL will illuminate.
- Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 35) Record any DTCs and freeze frame data. Switch scan tool to CHECK mode (Lexus scan tool only). Drive vehicle several times with engine speed, load and its surrounding range shown with ENGINE SPD, CALC LOAD in freeze frame data or MISFIRE RPM and MISFIRE LOAD in scan tool data list.
- Drive vehicle at specified engine speeds. See «DRIVING PATTERN»(ref-151781-S28696370722003010800000) table. Turn ignition off after symptom is simulated the first time, then repeat test drive again (OBD-II scan tool only). If a misfire is detected, a DTC will set and misfire will be indicated in freeze frame data. Turn ignition off and wait a minimum of 5 seconds. DRIVING PATTERN RPM (1) Minutes Idling 3 1/2 1000 3 2000 1 1/2 3000 1 (1) Minimum specification given.