P200E

P200E-CATALYST SYSTEM OVER TEMPERATURE - BANK 1







Theory of Operation

The After treatment Diesel Oxidation Catalyst is designed to react with hydrocarbons in the exhaust stream, this reaction produces heat. The heat can become excessive if too much hydrocarbon enters the After treatment Diesel Oxidation Catalyst too quickly. Excessive heat can damage the diesel after treatment components, so the temperature of the after treatment system is closely monitored by the electronic control module (ECM). The Exhaust Temperature sensors are used by the ECM to monitor the engine exhaust temperatures in the after treatment system. The Exhaust Temperature sensors are thermistors and change resistance based on the temperature being measured. The ECM provides a 5 Volt reference voltage to the sensor. The ECM monitors the voltage on the signal pin and converts this to a temperature value. When the exhaust gas temperature is cold, the sensor or thermistor resistance is high. The ECM signal voltage only pulls down a small amount through the sensor to ground. Therefore, the ECM senses a high signal voltage or low temperature. When the exhaust gas temperature is hot, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage, or a high temperature. The ECM illuminates the MIL lamp immediately when the diagnostic runs and fails. Active regeneration of the after treatment particulate filter will be disabled. The DTC can only be cleared by a scan tool.

- When Monitored:
The diagnostic runs continuously when the engine is running.

- Set Condition:
The Engine Control Module (ECM) detects that the after treatment diesel oxidation catalyst outlet temperature is greater than a calibrated temperature for a calibrated period.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. OTHER DTCS
1. Ignition on, engine not running.
2. With the scan tool, read DTCs.

Are any Fuel injector DTCs Active?

Yes

- Repair Fuel Injector DTCs.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. CYLINDER MISFIRE
1. Start the engine.
2. Allow the engine to idle.
3. With the scan tool, read the Misfire counter status.

Is an engine misfire detected?

Yes

- Determine the cause of the engine misfire. Use scan tool Cylinder Cutout Test to isolate a failed injector. Replace the failed injector if necessary. Inspect the after treatment system for possible damage.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. EXHAUST TEMPERATURE
1. With the scan tool, read the Exhaust Temperature Sensors to determine the exhaust temperature.

Is the temperature reading above 225°F?

Yes

- Go To 4

No

- Go To 5

4. EXHAUST TEMPERATURE SENSORS
1. Start the engine.
2. Raise the engine speed to 2500 RPM's for two minutes.

Does the temperature readings of all three Exhaust Temperature Sensors change in value at least 5°F?

Yes

- Go To 6

No

- Replace the Exhaust Temperature Sensor that did not change in value by at least 5°F or is not updating.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. EXHAUST TEMPERATURE SENSORS
1. Start the engine and allow it to idle for 10 minutes.
2. With the scan tool, read the values of all three Exhaust Temperature Sensors.

Do all three temperature sensors read above 150°F and are the values of the temperature sensors updating?

Yes

- Go To 6

No

- Replace the Exhaust Temperature Sensor that is not above 150°F or is not updating on the scan tool.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

6. EXCESSIVE ENGINE OIL BEING INTRODUCED INTO THE AFTER TREATMENT SYSTEM FROM THE ENGINE
1. Remove the turbocharger outlet and inspect for signs of oil, fuel or moisture being introduced into the after treatment system from the engine.

Was engine oil, fuel or moisture found in the turbocharger exhaust outlet?

Yes

- Locate the cause of possible diesel fuel or engine oil being carried from the engine into the after treatment system. Inspect the after treatment system for possible damage.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 7

7. AFTER TREATMENT SYSTEM
1. Remove and inspect the After treatment system.

Does After treatment Diesel Oxidation Catalyst show evidence of failure?

Yes

- Replace the After treatment Diesel Oxidation Catalyst.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.