P20E9

P20E9-(DIESEL EXHAUST FLUID) REDUCTANT PRESSURE TOO HIGH

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The DEF Pressure Sensor provides a signal to the DEF Dosing Control Unit on the sensor signal circuit. This sensor signal voltage changes based on the diesel exhaust fluid pressure supplied by the DEF Pump Assembly. The DEF Dosing Control Unit will detect a low signal voltage at low diesel exhaust fluid pressures, and high signal voltage at high diesel exhaust fluid pressures. The DEF Dosing Control Unit will illuminate the MIL light via the Powertrain Control Module (PCM) immediately after the diagnostics runs and fails and diesel exhaust fluid injection into the aftertreatment system is disabled. The DEF Dosing Control Unit will turn off the MIL light via the PCM immediately after the monitor runs and passes.

- When Monitored:
Continuously with the ignition on.

- Set Condition:
DEF Dosing Control Unit detects that the pressure in the system is above a calibrated value for 20 seconds.





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

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, navigate to Systems Tests and actuate the Diesel Exhaust Fluid Doser Pump Override Test.
3. With the scan tool, View DTCs.

Is the DTC active?

Yes

- Go To 2
NOTE: If any of the following DTCs are active with this DTC; P20A0, P20A2, P20A3, P20FE, P2048, P2049 or P208B, perform the diagnostics for those DTCs before continuing with this test procedure.

No

- Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. . Intermittent Condition Test

2. CHECK THE DEF LINES AND FITTINGS FOR LEAKS OR RESTRICTIONS
1. Turn the ignition off.
2. Visually inspect the DEF lines and fittings for signs of a leak.
3. Remove the lines from the fittings at the DEF Supply Pump Assembly and DEF Injector and inspect the fittings for signs of crystallization or blockages.

Were any leaks or blockages found?

Yes

- Repair or replace the leaking or blocked lines or fittings as necessary.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the DEF Pump Assembly Filter.
- Go To 3

3. CHECK THE DEF PUMP ASSEMBLY
1. Reconnect all of the DEF lines.
2. Remove the DEF Injector from the Decomp Tube. Diesel Exhaust Fluid Injector - Removal.
3. Place the DEF Injector in a container to capture the fluid sprayed.
4. Turn the ignition on.
5. With the scan tool, navigate to Systems Tests and actuate the Diesel Exhaust Fluid Doser Pump Override Test.

NOTE: This Test will run for six minutes before timing out. The amount of flow may fluctuate through out the test, therefore the test must be allowed to run completely in order for the results to be accurate. The fluid should spray out as a mist. There should be no dripping from the holes in the DEF Injector at any time during the duration of the test procedure.

6. Measure the amount of fluid sprayed after the test times out.

Does the fluid sprayed measure between 85 ml and 115 ml?

Yes

- Repair complete.

No

- Replace the DEF Pump Assembly. Diesel Exhaust Fluid Pump Assembly - Removal.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.