Test D - Air Cleaner Temperature (Act) Sensor Test (Code 24): Notes
- Check to verify that ACT sensor is seated in air cleaner. If installed properly, proceed with test. If not installed properly, correct and warm up engine before repeating Quick Test.
- Disconnect ACT connector, connect voltmeter positive lead to harness circuit 357 and negative lead to circuit 359. Turn ignition on and measure voltage. If voltage is more than 6 volts, perform Reference Voltage Test. If voltage is less than 4 volts, proceed to step 5). If voltage is between 4 and 6 volts, proceed to step 3).
- With ACT sensor disconnected, measure resistance across ACT sensor pins. If resistance is less than 1,100 ohms or more than 58,000 ohms, check heat stove duct valve operation. If valve operates properly, replace ACT sensor and repeat Quick Test. If resistance is between 1,100 and 58,000 ohms, proceed with test.
- With ACT sensor disconnected, run engine for 2 minutes and measure resistance across ACT sensor pins while engine is running. If resistance is less than 2,400 ohms or more than 29,000 ohms, check heat stove duct valve operation. If valve operates properly, replace ACT sensor and repeat Quick Test. If resistance is between 2,400 and 29,000 ohms, replace processor and repeat Quick Test.
- Turn ignition off and wait 10 seconds. Disconnect processor and inspect both 60 pin connectors. Connect breakout box to harness. Leave processor disconnected. Measure continuity from circuit 357 to breakout box pin 25 and circuit 359 to breakout box pin 46. If either resistance is 5 ohms or more, repair wiring harness and repeat Quick Test. If both resistances are less than 5 ohms, proceed with test.
- Turn ignition off and wait 10 seconds. Measure resistance between breakout box pin 25 and breakout box pins 40, 46 and 60. If any resistance is 10,000 ohms or less, repair short in harness and repeat Quick Test. If all resistances are more than 10,000 ohms, return to step 3).
- Check continuity of wire from knock sensor to MCU harness connector pin 14. If resistance is more than 5 ohms, repair wire. If resistance is 5 ohms or less, reconnect MCU and proceed with test.
- Reconnect the grounded jumper wire to the self-test connector. Connect a test lamp to the positive terminal of the battery. Disconnect the knock sensor.
- Repeat the "Engine Running Test" noting the following: When the initialization pulses occur, tap wire that leads to pin 14 of MCU with test lamp for 5 seconds. If diagnostic code 25 is displayed, replace MCU. If any other diagnostic code is displayed, replace knock sensor.