HANDLE AS 1566645 - Caterpillar

The exhaust back pressure is monitored by the exhaust pressure monitor. The inlet side of the Diesel Particulate Filter (DPF) contains a test port. The test port is for continuous monitoring of the exhaust back pressure. The warning lights in the engine compartment will illuminate in sequence. If the exhaust back pressure has exceeded 25 kPa (102 inch of H2O) for 15 seconds then the yellow light will turn on. If the exhaust back pressure has exceeded 25 kPa (102 inch of H2O) for more than 60 seconds then the amber light will turn on.If the yellow light is on at the end of the shift after many weeks of operation, this warning should be recorded. This is normal, particularly if only the yellow lamp is on at subsequent inspections. This means that the back pressure has stabilized at slightly higher conditions.The system should illuminate both lamps for 2 seconds as a system check at powerup. To cancel the lamps at the end of inspection, the system must be temporarily powered down.If the amber light is on at the end of the shift after many weeks of operation, this warning should be recorded. This means that the back pressure is rising. The engine should be checked at this point. Check for signs that could contribute to an increase in the production of soot that would cause the increase in back pressure such as excessive oil consumption, a shift in calibration, etc. The increase in back pressure could also be caused by an increase in idle or cooler operating conditions. Please contact your local Caterpillar dealer for advice in this area.If all of the checks are negative, it is possible that the back pressure has not stabilized.Note: With advice and assistance from your local Caterpillar dealer, it is possible to increase the settings of "Timer 2" by turning on switch "3" and by turning off switch "2". Turning on switch "3" will increase the time period from 1 minute to 2 minutes. The pressure setting should not be changed unless unusual circumstances are being investigated by your Caterpillar dealer. Unauthorized changes to the system will result in an impact to the warranty.If the amber light is still on after the update to the timer, closer examination and cleaning of the DPF will be necessary.In order to clean the DPF, refer to Operation and Maintenance Manual, "Exhaust Particulate Filter - Clean".In order to test the DPF, refer to Operation and Maintenance Manual, "Exhaust Particulate Filter - Test".Electrical
The monitor is operated on 12/24 VDC with a current supply of 25 mA. The monitor is protected with an internal fuse that is rated at 1.5 amp. The fuse has an automatic reset.
Illustration 1 g00917331
(1) Exhaust pressure monitor (2) Wire harness (3) Connection for tubing (4) TubingThe monitor has six electrical connections. The black wire (A) is the ground. The red wire (B) is switched power. The yellow wire (C) supplies power to the first warning. The green wire (D) grounds the first warning.