System Operation Description:
Table 1 lists the diagnostic codes that relate to the Aftertreatment Regeneration Devices absolute air pressure.
Note: Some of the following codes may not be applicable for certain applications.
| Diagnostic Trouble Codes | |||
|---|---|---|---|
| CDL Code | J1939 Code | Description | Comments |
| E1170 (1) | 3837-17 | Low Aftertreatment #1 Secondary Air Pressure | Air pressure to the combustion air valve is low. |
| E1170 (2) | 3837-18 | Low Aftertreatment #1 Secondary Air Pressure | Air pressure to the combustion air valve is low. |
| Follow the troubleshooting procedure in order to identify the root cause of the problem. | |||
System Operation
Note: The technician must perform a combustion air test in order to verify that the problem is corrected. If the problem has been resolved, perform a service regeneration before the unit is returned to service.
The combustion air system consists of the following components:
- Combustion air valve controller
- Combustion air valve
- Absolute pressure sensor
The combustion air valve controller receives operating voltage from the applications control system. The controller receives commands from the engine Electronic Control Module (ECM) via a CAN data link. The controller converts the commands from the ECM into a command signal for the combustion air valve. The controller also provides 5 VDC to the valve position sensor.
The combustion air valve positions an actuator according to the commands from the controller. The position sensor sends a signal to the controller. The signal indicates the position of the actuator.
The combustion air valve controller sends the position of the actuator to the engine ECM via the CAN data link. The position of the actuator can be viewed on Caterpillar Electronic Technician (ET). The controller also sends diagnostic information to the ECM.
The absolute pressure sensor converts the absolute pressure of the combustion air into an electrical signal. The ECM uses the signal to determine the volume of combustion air that is being provided to the ARD. The ECM changes the command to the combustion air controller until the volume of combustion air is correct.
Illustration 1 shows the location of the components for the combustion air system.
Illustration 1 g02220193
CEM (typical)
(1) Piping for the combustion air
(2) Combustion air valve
(3) Pressure sensor for the inlet of the combustion air
(4) DPF differential pressure sensor
(5) Cable for CEM connector to the ECM
(6) Actuator for the combustion air valve
(7) Inlet for the combustion air valve
(8) Inlet for the combustion air to the ARD head
(9) ARD head
| Troubleshooting Test Steps | Values | Results |
| 1. Check for Associated Diagnostic Trouble CodesA. Download the “Warranty Report” from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
B. Table 3 lists the diagnostic trouble codes that are associated with an E1170 (2)/ 3837-18 code. Determine if any of the codes in Table 3 are present. C. Determine the diagnostic code that is present. |
Diagnostic code | Result: An associated diagnostic trouble code is not present.Proceed to Test Step 2.
Result: An associated diagnostic trouble code is present. Troubleshoot the associated code. STOP. |
| 2. Inspect the Piping Between the Compressor and the ATAACA. Visually Inspect the piping between the compressor and the ATAAC.
B. Check for cracks in the piping. C. Check for loose hardware or damaged hardware. |
Damaged or cracked piping | Result: The piping is damaged or cracked.Replace the piping or repair the piping. Proceed to Test Step 6.
Result: The piping is not damaged or cracked. Proceed to Test Step 3. |
| Associated Diagnostic Trouble Codes | |
|---|---|
| CDL Code | J1939 Code |
| E1045 | 102 |
| E1156 | 3609 |
| 2489 | 3487 |
| 2490 | 3488 |
| 3471 | 5591 |
| 3472 | 5591 |
| 3493 | 3837 |
Illustration 2 g01958186
(10) Piping between the compressor and the air valve
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
| 3. Inspect the Piping Between the Compressor and the Air ValveA. Inspect the piping (10) between the compressor and the air valve.
B. Check for cracks in the piping. C. Check for loose hardware or damaged hardware. |
Damaged or cracked piping | Result: The piping is damaged or cracked.Replace the piping or repair the piping. Proceed to Test Step 6.
Result: The piping is not damaged or cracked. Proceed to Test Step 4. |
Illustration 3 g02220233
CEM (typical)
(11) Clamps
(12) Piping between the combustion air valve and the pressure sensor
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
|
4. Inspect the Piping from the Combustion Air Valve to the Pressure Sensor
A. Inspect the piping from the combustion air valve to the pressure sensor (12). B. Check for air leaks. C. Check for loose hardware or damaged hardware. D. Check the clamps on the piping. Make sure that the clamps are tight. |
Damaged or cracked piping or air leaks |
Result: The piping is damaged or cracked.
Replace the piping or repair the piping. Proceed to Test Step 6. Result: The piping is not damaged or cracked. Proceed to Test Step 5. |
|
5. Inspect the Turbocharger
A. Refer to the Reuse and Salvage Guidelines in order to determine if the turbocharger has failed. |
Failed turbocharger |
Result: The turbocharger has failed.
Replace the turbocharger. Proceed to Test Step 6. Result: The turbocharger has not failed. Proceed to Test Step 6. |
|
6. Perform the “ARD Air System Service Test”
A. Perform the “ARD Air System Service Test”. |
Successful test |
Result: The test completed successfully.
Perform a “Manual DPF Regeneration” and return the unit to service. STOP Result: The test did not complete successfully. Troubleshoot the logged diagnostic code. STOP |
Test Step 1.
Complete the procedure in the order in which the steps are listed.
Results:
- The procedure corrected the issue. – STOP
- The procedure did not correct the issue. –Repair: Contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).
STOP