Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

Ignition Off
Test the reductant system for contamination. Refer to Contaminants-in-Diesel Exhaust Fluid Diagnosis .
- If any conditions are found
  Repair as necessary.
- Go to next step: If no conditions are found
Ignition - On/Vehicle - In Service Mode
Perform the scan tool control function: Reductant System Leak Test - ON
Verify that the system is able to build up and reach the reductant pressure sensor parameter greater than 450 kPa.
- If less than the specified range
1. Command the Reductant Pump to 50% with a scan tool.
2. Verify the scan tool parameter: Desired Reductant Pump Speed = Reductant Pump Speed
  - If not equal
    Refer to DTC P105A
  - Go to next step: If equal
- Go to next step: If within the specified range
Verify there are no leaks, kinks or restrictions in the reductant lines
- If any condition is found
  Repair as necessary.
- Go to next step: If no conditions are found
Remove the Q61 Reductant Injector from the exhaust pipe leaving the reductant line and electrical connector connected.
Place the injector into a suitable container, Perform the Emission Reduction Fluid Injector Quantity Test refer to Reductant Injection Quantity Test
- If the test does not pass
  Repair as necessary.
- Go to next step: If the test passes
Disconnect the Q61 Reductant Injector electrical connector.
Engine running and NOx sensors at operating temperature, verify NOx sensor 2 NOx Concentration is less than 50 ppm greater than NOx sensor 1 NOx Concentration.
- If NOx sensor 2 NOx Concentration is 50 ppm or greater than NOx sensor 1 NOx Concentration
  Replace the B195B Nitrogen Oxides Sensor 2
- Go to next step: If NOx sensor 2 NOx Concentration is less than 50 ppm greater than NOx sensor 1 NOx Concentration
Idle engine at 1500 RPM for 10 min while monitoring Exhaust Gas Temperature Sensor 2.
Verify Exhaust Gas Temperature Sensor 2 is colder than 150°C (302°F)
- If 150°C (302°F) or warmer
1. Verify Exhaust Gas Temperature Sensor 2 is warmer than 150°C (302°F) For greater than 30 min, then continue to the next step.
- Go to next step: If colder than 150°C (302°F)
Verify NOx sensor 1 NOx Concentration and NOx sensor 2 NOx Concentration are within 50 ppm of each other.
- If not within 50 ppm
  Replace the B195A Nitrogen Oxides Sensor 1
- Go to next step: If within 50 ppm
Connect the Q61 Reductant Injector electrical connector.
Verify none of the conditions listed below exist:
- Leaking fuel injectors. Refer to Fuel Injector Balance Test with Scan Tool .
- Engine oil consumption. Refer to Oil Consumption Diagnosis .
- Engine coolant consumption. Refer to Coolant in Combustion Chamber .
- An engine mechanical condition. Refer to Symptoms - Engine Mechanical .
- If any condition is found
  Repair as necessary
- Go to next step: If no condition is found
Replace SCR Catalyst.