ROD-CONN-YM 3798864 - Caterpillar

This procedure covers the following codes:
Table 1
Diagnostic Trouble Codes for the Engine Pressure Sensors
J1939 Code Description Notes
1209-3 Engine Exhaust Gas Pressure : Voltage Above Normal The ECM detects the following conditions:
The signal voltage from the exhaust gas pressure sensor is greater than 4.74 VDC for at least 1.8 seconds.
The battery voltage is at least 10 VDC.
The ECM will use the default value for exhaust gas pressure while this code is active. The default value is 50 kPa (7.25 psi).
The engine will be derated.
1209-4 Engine Exhaust Gas Pressure : Voltage Below Normal The ECM detects the following conditions:
The signal voltage from the exhaust gas pressure sensor is less than 0.4 VDC for at least 1.8 seconds.
The battery voltage is at least 10 VDC.
The ECM will use the default value for exhaust gas pressure while this code is active. The default value is 50 kPa (7.25 psi).
The engine will be derated. The following conditions must exist before any of the above codes will become active:
There are no active 3509 codes.
There are no active 168 codes.The following background information is related to this procedure:The 5 VDC sensor supply provides power to all 5 VDC sensors. The ECM supplies 5.0 0.1 VDC to each of the pressure sensor connectors. The sensor supply is output short circuit protected. A short circuit to the battery will not damage the circuit inside the ECM.
Illustration 1 g03622560
Schematic diagram for the exhaust gas pressure sensor
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 2 g03118316
Typical view of the pin locations on the P2 connector for the pressure sensors
(12) Exhaust gas pressure sensor 5 VDC supply
(27) Exhaust gas pressure sensor ground
(43) Exhaust gas pressure sensor signal
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Thoroughly inspect the terminal connections on the P2/J2 ECM connector. Refer to Troubleshooting, "Electrical Connectors - Inspect".
B. Thoroughly inspect the connector for the exhaust gas pressure sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
C. Perform a 30 N (6.7 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the exhaust gas pressure sensor.
D. Check the harness for abrasions and for pinch points from the exhaust gas pressure sensor back to the ECM.
Damaged wire or connector
Result: A damaged wire or damaged connector was found. A fuse is blown.
Repair the damaged wire or the damaged connector. Replace any blown fuses
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly connected and/or inserted and the harness is free of corrosion, of abrasion or of pinch points.
Proceed to Test Step 2.
2. Check For Active Diagnostic Codes
A. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.
B. Verify if any of the diagnostic codes that are listed in Table 1 are active.
Diagnostic codes
Result: None of the preceding diagnostic codes are active.
If the codes in Table 1 are logged, an intermittent