System Operation Description:
Use this procedure to troubleshoot the electrical system if a problem is suspected with the oxygen sensors. Also, use this procedure if one of the diagnostic codes in Table 1 is active or easily repeated.
| J1939 Code and Description | Comments |
|---|---|
| 3221-2
Aftertreatment #1 Intake Wide-Range O2 Reading Stable : Erratic, Intermittent, or Incorrect |
The catalyst intake oxygen sensor has detected an internal problem which results in data that is unstable and/or not in the correct format. Replace the oxygen sensor |
| 3221-3
Aftertreatment #1 Intake Wide-Range O2 Reading Stable : Voltage Above Normal |
The catalyst intake oxygen sensor has detected high supply voltage at the sensor. The code is logged. |
| 3221-4
Aftertreatment #1 Intake Wide-Range O2 Reading Stable : Voltage Below Normal |
The catalyst intake oxygen sensor has detected low supply voltage at the sensor. The code is logged. |
| 3221-12
Aftertreatment #1 Intake Wide-Range O2 Reading Stable : Failure |
The catalyst intake oxygen sensor has detected an internal problem with the sensor. Replace the oxygen sensor. |
| 3221-14
Aftertreatment #1 Intake Wide-Range O2 Reading Stable : Special Instruction |
The catalyst intake oxygen sensor has detected an internal problem with the sensor heating element. The sensor was unable to reach operating temperatures within the predetermined amount of time. Replace the oxygen sensor. |
| 3222-12
Aftertreatment #1 Intake Gas Sensor Heater Preliminary FMI : Failure |
The catalyst intake oxygen sensor has detected an internal problem with the sensor heating element. Replace the oxygen sensor. |
| 3231-2
Aftertreatment #1 Outlet Wide-Range O2 Reading Stable : Erratic, Intermittent, or Incorrect |
The catalyst intake oxygen sensor has detected an internal problem which results in data that is unstable and/or not in the correct format. Replace the oxygen sensor |
| 3231-3
Aftertreatment #1 Outlet Wide-Range O2 Reading Stable : Voltage Above Normal |
The catalyst intake oxygen sensor has detected high supply voltage at the sensor. The code is logged. |
| 3231-4
Aftertreatment #1 Outlet Wide-Range O2 Reading Stable : Voltage Below Normal |
The catalyst intake oxygen sensor has detected low supply voltage at the sensor. The code is logged. |
| 3231-12
Aftertreatment #1 Outlet Wide-Range O2 Reading Stable : Failure |
The catalyst intake oxygen sensor has detected an internal problem with the sensor. Replace the oxygen sensor. |
| 3231-14
Aftertreatment #1 Outlet Wide-Range O2 Reading Stable : Special Instruction |
The catalyst intake oxygen sensor has detected an internal problem with the sensor heating element. The sensor was unable to reach operating temperatures within the predetermined amount of time. Replace the oxygen sensor. |
| 3232-12
Aftertreatment #1 Outlet Gas Sensor Heater Preliminary FMI : Failure |
The catalyst intake oxygen sensor has detected an internal problem with the sensor heating element. Replace the oxygen sensor. |
The oxygen sensors are used to monitor the emission level of the engine exhaust by measuring the oxygen concentration in the exhaust stream. The Electronic Control Module (ECM) utilizes the signal from the oxygen sensors to adjust the air/fuel ratio. This strategy ensures that the engine burns the fuel efficiently. Two oxygen sensors are used for this application. One of the oxygen sensors is mounted in the turbocharger exhaust outlet. The other oxygen sensor is mounted in the output flange of the catalytic converter. Each sensor circuit consists of an oxygen sensor and a voltage converter that is used to power both sensor circuits.
The sensors generate a signal that is proportional to the concentration of oxygen which is relayed to the engine ECM via the CAN data link. This type of sensor is considered to be a “smart” sensor which 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 exposure. Each oxygen sensor utilizes a heating element to heat the sensing element of the sensor. The use of the heating element improves the warmup time and the accuracy of the sensor.
Note: The sensors have an operating range of
The voltage converter converts a filtered 24 VDC from the battery to 12 VDC that is used by the sensor circuit. The voltage convertor is powered and enabled by a 24VDC switched power supply from the engine ECM. The voltage converter provides 12 VDC to each of the oxygen sensors.
If a -9 abnormal update rate diagnostic is active for the oxygen sensor circuit, verify the 24 VDC switched power to the voltage converter is present at the voltage converter input B. If the converter is not powered by the 24 VDC switched power, the 12 VDC regulated oxygen sensor power supply will also not be enabled. Refer to the CAN Data Link Test for additional CAN data link circuit test procedures.
| |
| Illustration 1 | g02402537 |
|
Schematic of the circuit for the oxygen sensor | |
Test Step 1. Inspect the Electrical Connectors and the Wiring
- Remove the electrical power from the engine.
- Check the fastener on each ECM connector for the proper torque. Refer to Testing and Adjusting, "Electrical Connectors - Inspect" for the correct torque values.
- Check the harness and the wiring for abrasion and for pinch points.
Expected Result:
All connectors, pins, and sockets are coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion and of pinch points.
Results:
- OK - The connectors and wiring appear to be OK. A -3 diagnostic is active or logged. Proceed to Test Step 2. A -4 diagnostic is active or logged. Proceed to Test Step 4.
- Not OK - The connectors and/or wiring are not OK.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring.
STOP
Test Step 2. Check the Voltage at the Voltage Convertor Output
- Measure the voltage between terminal E (convertor 12 V output) and terminal C (convertor ground).
Expected Result:
The voltage between terminal E and terminal C less than 18 V.
Results:
- OK - Voltage measured at the convertor output terminal E is less than 18 V. Proceed to Test Step 3.
- Not OK - Voltage measured at the convertor output terminal E is greater than or equal to 18 V.
Repair: Replace the voltage convertor.
STOP
Test Step 3. Check the Voltage at the Oxygen Sensor Input
- Measure the voltage between terminal 1 of the oxygen sensor and sensor ground terminal 2.
Expected Result:
The voltage between terminal 1 and terminal 2 is 18 V.
Results:
- Not OK - The voltage measured at the oxygen sensor is greater than 18 V.
Repair: There is a short to power in between the convertor and the sensor. Repair or replace the wiring between the sensor and the convertor.
STOP
- Not OK - The voltage measured at the oxygen sensor power supply input is less than 18 V.
Repair: Replace the Oxygen Sensor.
STOP
Test Step 4. Check the Voltage at the Voltage Convertor INput
- Measure the voltage between terminal A of the voltage convertor and terminal C (convertor ground).
Expected Result:
The voltage between terminal A and terminal C is greater than 18 V.
Results:
- OK - The battery voltage is greater than 18 V at the convertor power supply input terminal A. Proceed to Test Step 5.
- Not OK - The battery voltage is less than 18 V at the convertor power supply input terminal A.
Repair: Check wiring, fuses, and power in between the convertor and the engine battery power supply.
STOP
Test Step 5. Check the Output Voltage at the Voltage Converter
- Measure the voltage between terminal E (convertor 12 V output) and terminal C (convertor ground).
Expected Result:
The voltage between terminal E and terminal C is 10 V or greater.
Results:
- OK - The regulated voltage from the convertor is greater than 10 V. Proceed to Test Step 6.
- Not OK - The regulated voltage from the convertor is less than 10 V.
Repair: There is a problem with the voltage convertor. Replace the voltage convertor.
STOP
Test Step 6. Check the Voltage at the Oxygen Sensor Input
- Measure the voltage between terminal 1 of the oxygen sensor and sensor ground terminal 2.
Expected Result:
The voltage between terminal 1 and terminal 2 is 10 V.
Results:
- Not OK - The regulated voltage is greater than 10 V.
Repair: Replace the Oxygen Sensor.
STOP
- Not OK - The regulated voltage is less than 10 V.
Repair: There is a problem with the wiring between the sensor and the convertor.
STOP