The air filter restriction lamp illuminates in order to indicate that the air filter is plugged. When the air filter restriction lamp is illuminated, the ECM has detected a significant reduction in the air flow from the air filter.
One terminal of the air filter restriction lamp is connected to battery voltage through the machine wiring and the other terminal is connected to the ECM at P1:29. The ECM provides a path to ground for the lamp. When the ECM connects the lamp to ground, the lamp will turn on.
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| Illustration 1 | g00831202 |
Schematic | |
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| Illustration 2 | g01011208 |
P1 ECM connector | |
Test Step 1. Inspect Electrical Connectors and Wiring
- Thoroughly inspect the J1/P1 ECM connector, any other connectors in the circuit, the air filter restriction lamp, and the associated wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
- Perform a 45 N (10 lb) pull test on the wire for the air filter restriction lamp.
- Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).
- Check the harness and wiring for abrasions and for pinch points from the battery to the ECM.
Expected Result:
All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion, or of pinch points.
Results:
- OK - Proceed to Test Step 2.
- Not OK -
Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.
STOP
Test Step 2. Check for Normal Operation of the Lamp
- Monitor the air filter restriction lamp while you turn the keyswitch to the ON position.
- Turn the keyswitch to the OFF/RESET position.
Expected Result:
The air filter restriction lamp illuminates for five seconds when the keyswitch is turned to the ON position.
Results:
- OK - The air filter restriction lamp appears to operating correctly at this time.STOP
- Not OK - Lamp Does Not Illuminate - The lamp does not illuminate during the lamp check. Proceed to Test Step 3.
- Not OK - Lamp Remains On - The lamp remains on after the lamp check. Proceed to Test Step 5.
Test Step 3. Check for Power at the Lamp
- Turn the keyswitch to the ON position.
- Use a voltage test lamp to check for power between the air filter restriction lamp and chassis ground. Check both terminals on the lamp socket.
Note: If the test lamp only lights on one side of the socket, the bulb is blown.
Expected Result:
The test lamp illuminates.
Results:
- OK - The lamp is receiving power and the bulb is good. Proceed to Test Step 4.
- Not OK - Power On One Side - The lamp is receiving power, but the bulb does not illuminate.
Repair: Replace the bulb.Verify that the repair eliminates the problem.
STOP
- Not OK - No Power - The lamp is not receiving power.
Repair: Repair the power circuit to the lamp. Refer to the Electrical Schematic for more details.
STOP
Test Step 4. Check for Power at the ECM
- Disconnect the J1/P1 ECM connector.
- Turn the keyswitch to the ON position.
- Use a voltage test lamp to check for power between P1:29 and engine ground.
- Turn the keyswitch to the OFF/RESET position.
Expected Result:
The test lamp illuminates.
Results:
- OK - The circuit from the ECM to the air filter restriction lamp appears to be good. Proceed to Test Step 6.
- Not OK - There is an open circuit between the ECM and the air filter restriction lamp.
Repair: Repair the open circuit.Verify that the repair eliminates the problem.
STOP
Test Step 5. Check the Harness for a Short to Ground
- Disconnect the J1/P1 ECM connector.
- Remove the bulb for the air filter restriction lamp from the socket.
- Measure the resistance between P1:29 (Air Filter Restriction Lamp) and engine ground.
- Reconnect the J1/P1 ECM connector.
Expected Result:
The resistance is greater than 20,000 Ohms.
Results:
- OK - The wire is not shorted to ground. Proceed to Test Step 6.
- Not OK - The 430-BU wire is shorted to ground between the ECM and the air filter restriction lamp.
Repair: Repair the circuit.Verify that the repair eliminates the problem.
STOP
Test Step 6. Check the ECM
- Ensure that the J1/P1 ECM connector is connected.
- Remove the 430-BU wire from P1:29.
- Install a voltage test lamp between the +Battery and P1:29.
- Monitor the test lamp while you turn the keyswitch to the ON position.
Expected Result:
The test lamp illuminates for five seconds when the keyswitch is turned to the ON position.
Results:
- OK - The ECM and the circuit appear to be working properly at this time.
Repair: If an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for more details.
STOP
- Not OK - The ECM is not functioning properly.
Repair: Verify your results. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.Verify that the repair eliminates the problem.
STOP