966723 Volvo.Penta Peg

Illustration 1 g03711103Probable Causes
Codes
Sensor
Sensor connector
Data link Recommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Establish communication between Cat® Electronic Technician (ET) and the ECM.
B. Turn the DC breaker to the ON position.
C. Look for active codes.
Diagnostic Codes
Result: A -12 code is active.
Repair: Replace the failed NOx sensor.
Refer to Special Instruction,, REHS8151 for special handling instructions.
Proceed to Test Step 6.
Result: A -9 code is active.
Check to ensure the NOx sensors are connected to the wiring harness.
Proceed to Test Step 2.
2. Inspect the NOx Sensor Power Supply Wiring
A. Turn the DC breaker to the OFF position.
B. Disconnect the suspect NOx sensor from the wiring harness.
C. Turn the DC breaker to the ON position.
D. Measure the voltage between pin 1 (SUPPLY) and pin 4 (RETURN) on the suspect NOx sensor connector.
Battery Voltage
Result: Battery voltage is present at the NOx sensor connector.
Proceed to Test Step 5.
Result: Battery voltage is not present at the NOx sensor connector.
If the problem is not resolved, proceed to Test Step 3.
3. Check for Power at the Suspect NOx Sensor Connector
A. Turn the DC breaker to the OFF position.
B. Disconnect the suspect NOx sensor from the wiring harness.
C. Turn the DC beaker to the ON position.
D. Measure the voltage between pin 1 (SUPPLY) on the suspect NOx sensor connector and a known good ground.
Battery Voltage
Result: The voltage is equal to battery voltage.
Proceed to Test Step 4.
Result: The voltage is not equal to battery voltage.
There is a problem with the power supply circuit between the suspect NOx sensor connector and the aftertreatment ECM. Refer to the appropriate schematic.
Repair: Repair or replace the wiring harness as necessary.
If the problem is not resolved, proceed to Test Step 6.
4. Check the Ground at the Suspect NOx Sensor Connector
A. Turn the DC breaker to the OFF position.
B. Disconnect the suspect NOx sensor from the wiring harness.
C. Measure the resistance between pin 4 (RETURN) on the suspect NOx sensor connector and a known good ground.
Less than 10 ohms
Result: More than 10 ohms of resistance between pins 4 (RETURN) and a known good ground.
There is a problem with the ground to between the suspect NOx sensor connector and the aftertreatment ECM. Refer to the appropriate schematic.
Repair: Repair or replace the wiring harness as necessary.
If the problem is not resolved, proceed to Test Step 6.
5. Check the Data Link
A. Turn the DC breaker to the OFF position.
B. Disconnect the suspect NOx sensor from the wiring harness.
C. Measure the resistance between pin 5 (J1939 (-)) and pin 6 (J1939 (+)) on the suspect NOx sensor connector
60+/-10 Ohms
Result: The resistance is less than 50 Ohms.
There are more than two terminating resistors installed in the wiring harness or a short circuit has been detected.
Repair: Repair or replace parts as necessary. Refer to the appropriate wiring diagram.
Proceed to Test Step 6.
Result: The resistance is 60 10 Ohms. The terminating resistors are OK.
A failed NOx Sensor has been detected. Replace failed the NOx sensor. Refer to Special Instruction,, REHS8151 for special handling instructions.
Proceed to Test Step 6.
Result: The resistance is 120 10 Ohms.
There is a problem with a terminating resistor.
Check the resistance on each terminating resistor. Replace the failed terminating resistor.
Proceed to Test Step 6.
Result: The resistance is greater than 130 Ohms.
There is a problem with both terminating resistors or an open circuit has been detected. Determine the cause of the problem.
Repair: Repair the problem, when possible. replace parts, if necessary. Verify that the problem is resolved.
If the problem is not resolved, proceed to Test Step 6.
6. Operate the Engine
A. Start the engine and allow the engine to reach normal operating temperature.
B. Connect Cat ET.
C. Monitor the "Aftertreatment System State".
D. Check for fault codes when the "Aftertreatment System State" reads "Normal Dosing".
Fault Codes
Result: No fault codes active.
Return to Service.
Result: A -9 or -12 code comes active while running the engine.
Contact your TC for assistance.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).