| CAUTION | If Engine Control Module (ECM) replacement is instructed in following test, always ensure ECM electrical connectors and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
Direct Ignition System (DIS) ignites 2 cylinders simultaneously with one ignition coil. Ignitor is integral to ignition coil. Direct ignition system may also be referred to as distributorless ignition system. ECM determines ignition timing and outputs ignition signal (IGT signal) for each cylinder. Based on IGT signals, ignitor controls primary ignition signals (IGC) for all ignition coils. At the same time, the ignitor delivers an ignition confirmation signal (IGF signal) to ECM to verify ignition coil has fired. DTC is set when there is no IGF signal to ECM for 3 consecutive times during 6 consecutive IGT signals while engine is running. If DTC P1300 exists, ECM will operate in fail-safe mode. Possible causes are
- Ignition system malfunction.
- IGF or IGT circuit from ignition coil to ECM is open or shorted.
- Defective ignition coil or ignitor.
- Defective ECM.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.
Scheme 137
- Check for spark at misfiring cylinder by performing spark test. See «SPARK TEST»(ref-133197-S27511875622002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
- Check for open and short in IGF circuit (Black/Yellow wire) and electrical connectors between terminal No. 2 at ECM electrical connector E7 and terminal No. 4 at ignitor. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 For ECM electrical connector terminal identification see scheme 4 Ignitor is located at passenger's side of engine compartment, just behind the air cleaner assembly and contains a Black 10-pin electrical connector. For ignitor electrical connector terminal identification (Scheme 137) If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
- Disconnect Black 10-pin electrical connector at ignitor. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Yellow wire) at ECM electrical connector E7. see scheme 4 This is the IGF terminal on ECM. Voltage should 4.5-5.5 volts. If voltage is within specification, replace ignitor. If voltage is not within specification, replace ECM.
- Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Check for open and short in IGT1 circuit (Black/Blue wire), IGT2 circuit (Light Green/Red wire) and IGT3 circuit (Black/White wire) and electrical connectors between ECM and ignitor. See «WIRING DIAGRAMS»(ref-133228) article. For ECM electrical connector terminal identification see scheme 4 Ignitor is located at passenger's side of engine compartment, just behind the air cleaner assembly and contains a Black 10-pin electrical connector. For ignitor electrical connector terminal identification (Scheme 137) If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
- Using voltmeter, check voltage between body ground and terminals No. 9 (Black/White wire), No. 10 (Light Green/Red wire) and No. 11 (Black/Blue wire) at ECM electrical connector E7 while cranking engine. see scheme 4 This is the IGT3, IGT2 and IGT1 terminals on ECM. Voltage should be more than.1 volt and less than 4.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 7.
- Disconnect electrical connector at ignitor. Using voltmeter, check voltage between body ground and terminals No. 9 (Black/White wire), No. 10 (Light Green/Red wire) and No. 11 (Black/Blue wire) at ECM electrical connector E7 while cranking engine. see scheme 4 Voltage should be more than.1 volt and less than 5.0 volts. If voltage is not within specification, replace ECM. If voltage is within specification, replace ignitor.
- Disconnect electrical connector at ignitor. Using voltmeter, check voltage between body ground and terminal No. 9 (Black/Red wire) at electrical connector for ignitor with ignition switch in ON and START positions. (Scheme 137) Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, repair Black/Red wire between ignition switch and ignitor. See «WIRING DIAGRAMS»(ref-133228) article.
- Check for open and short in wiring harness and electrical connectors between ignition switch and ignition coils, and between ignition coils and ignitor. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair components as necessary.
- Check ignition coil resistance. See «IGNITION COIL RESISTANCE»(ref-133197-S21092330792002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If ignition coil is okay, go to next step. If ignition coil is defective, replace ignition coil.
- Verify that Brown wire for the ground circuit between terminal No. 3 at ignitor and ground connection are okay. See «WIRING DIAGRAMS»(ref-133228) article. If ground circuit is okay, replace ignitor. If ground circuit is defective, repair as necessary.