P1300

P1300 on Toyota is an Igniter Circuit Malfunction, set when the ECM does not see the expected IGF (ignition confirmation) feedback pulse from the igniter after firing an IGT (ignition trigger) command to a coil. On older distributor-and-igniter Toyotas (1990s 5S-FE, 3S-GTE, 7M-GE, 2JZ-GE) the igniter is a standalone module bolted to the distributor or inner fender; on coil-on-plug Toyotas the igniter is integrated into each coil pack and P1300 fires only for cylinder 1's circuit. Start cheap: pull the coil or igniter connector, inspect for melted plastic or green corrosion on the IGT and IGF pins, swap coil 1 with coil 3 to see if the fault follows the coil, and verify a clean ground at the igniter ground stud (resistance to battery negative should be under 0.5 ohms). Then check IGT pulse with a noid light or scope; you should see a clean 5V square wave at cranking. The expensive misdiagnosis is replacing all four or six coils, then the ECM, when the real fault is a corroded igniter ground at the cylinder head, a broken IGF return wire under the intake plenum, or carbon-tracked spark plug boots arcing the IGF signal to ground.

Vehicle-specific patterns: Toyota 3S-GTE turbo (MR2 Turbo, Celica All-Trac 1990-1999) is the classic P1300 platform; the fender-mounted igniter (Toyota part 89621-26010 or similar) cooks from underhood heat and typically fails between 100k and 180k miles. Toyota 2JZ-GE and 2JZ-GTE (Supra, GS300, IS300 1993-2005) sets P1300 from the coil-pack-integrated igniter on cylinder 1 or from a chafed IGF wire where the harness crosses the valve cover bolts. Toyota 1MZ-FE 3.0L V6 (Camry, Avalon, ES300 1994-2003) sees P1300 most often from the igniter mounted on the air-intake side of the engine bay, which is a $60 to $90 OE part replacement. Toyota 5S-FE 2.2L (Camry, Celica 1992-2001) typically sets P1300 from distributor cap moisture intrusion or igniter failure. Estimated repair: $90 to $640.