Ignition Timing: 4-Cylinder: Highlander

If using Toyota hand-held tester, ignition timing may be read on hand-held tester by connecting hand-held tester to data link connector No. 3, starting engine and with engine idling and at normal operating temperature, read ignition timing. Data link connector No. 3 is located below driver's side of instrument panel. See Figure. Following procedure is without Toyota hand-held tester.Start engine and warm engine to normal operating temperature. Shut engine off. Remove engine cover located on top of engine, above ignition coils and valve cover. Pull wire from wiring harness near ignition coil for cylinder No. 1 so timing light may be connected. See Fig 1. Cylinder No. 1 is front cylinder at timing chain end of engine. Connect timing light lead to the wire in wiring harness.

Fig 1: Locating Wire For Connecting Timing Light (Highlander)
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Apply parking brake. Place transaxle in Neutral. Note location of data link connector No. 3 below driver's side of instrument panel. See Figure. Install Jumper Wire (SST 09843-18020) between terminals No. 4 (CG) and 13 (TC) on data link connector No. 3. See Figure. Start engine. Engine speed should increase to 1000-1300 RPM for 5 seconds and return to idle.
Check ignition timing with engine idling. Timing marks are located on timing chain cover, near crankshaft pulley. Ensure base timing is within specification at idle with transaxle in Neutral, and with A/C, electric cooling fan and all accessories off. See IGNITION TIMING SPECIFICATIONS table.
Remove jumper wire from data link connector No. 3. Ensure ECM controlled timing is within specification. See IGNITION TIMING SPECIFICATIONS table. Increase engine speed and check that ignition timing advances when engine speed is increased. Allow engine to idle. Shut engine off. Remove timing light. Tape wire back to wiring harness. Reinstall engine cover.