VALVE GP-CONTROL 1878637 - Caterpillar

The oxygen sensor is used to monitor the emission level of the engine exhaust by measuring the oxygen concentration in the exhaust stream. The ECM utilizes the signal from the oxygen sensor to adjust the air/fuel ratio. This strategy ensures that the engine burns the fuel efficiently. One oxygen sensor is used for this application. The oxygen sensor is mounted at the catalyst inlet. The sensor circuit consists of an oxygen sensor and a voltage converter that is used to power the sensor circuit. The sensor generates a signal that is proportional to the concentration of oxygen which is communicated to the engine ECM via the CAN data link. This type of sensor is a wideband oxygen sensor that can self-diagnose internal problems. The sensor will notify the engine ECM of an issue when detected. Some diagnostics reported from the Oxygen sensor will indicate that the sensor has failed and will need replaced. If repeat failures occur, check the sensor installation for any contributing factors such as exposure to moisture or wiring harness high heat exposureThe oxygen sensor exposure limits should not exceed the following:- Controller ambient temperature range -40 to 105 C- Grommet temperature greater than 240 C- Cable temperature greater than 200 CEach oxygen sensor utilizes a heating element to heat the sensing element of the sensor.Note: The sensor has an operating range of 600° C to 800° C (1100° F to 1500° F). The tip of the sensor may be hot. Use caution when you handle the oxygen sensor.To operate, the oxygen sensor requires a supply voltage in the range of 10-18 Volts DC.A voltage converter converts the 24 VDC from the battery to 12 VDC that is used to power each of the oxygen sensor.The voltage convertor is enabled and disabled by a 24VDC output from the engine ECM.When the voltage convertor is disabled, the 12 VDC to the oxygen sensor will be turned off.If the oxygen sensor looses the 12 VDC supply when the ECM is enabling the voltage converter, the ECM will detect the loss of communication and issue a -9 abnormal update rate CAN data link fault for the component.If a -9 abnormal update rate diagnostic is active for the oxygen sensor, ensure the following are true:- 24 VDC at the voltage converter terminal 2 when the ECM is enabling the converter.- 12 VDC at the oxygen sensor terminal 1 when the ECM is enabling the converter.Refer to Troubleshooting , Data Link - Test for additional information on -9 codes.
Illustration 1 g06303526
For the complete circuit details, refer to the full schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.
C. Perform a 45 N (10 lb) pull test on the connector wires.
D. Check the harness for abrasions and pinch points.
Connectors and Wiring
Result: The connectors and wiring appear to be OK.
Proceed to Test Step 2.
Result: There is a problem