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Home >> Jeep >> 2018 >> Grand Cherokee Laredo, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (3.0L Diesel - DTCS P1693-00 To P2200-00) >> DTC Troubleshooting >> P20E8-00-REDUCTANT Pressure Too Low >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECK THE DEF TANK LEVEL AND FLUID 
    NOTE:

    Inspect the Diesel Exhaust Fluid before continuing with this Diagnostic Tree. If there is evidence of contamination or degraded fluid; Perform the Diagnostic and Testing - Diesel Exhaust Fluid procedure.

    Refer to DIESEL EXHAUST FLUID EMISSIONS, DIAGNOSIS AND TESTING .

    1. Verify the DEF Tank level.
    2. Check the fluid for signs of contamination.

      Is the fluid level in the DEF Tank above the minimum requirement and free of contamination?

      Yes 

      • Go To  2

      No 

      • Fill the DEF Tank to the proper level with clean Diesel Exhaust Fluid. If the fluid is contaminated, perform the cleaning procedure.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  2. CHECK FOR AN ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, record all Freeze frame data and record all DTCs on the repair order.
    3. With the scan tool, erase DTCs.
    4. Turn the ignition off for 75 seconds.
    5. Turn the ignition on, run the engine to operating temperature
    6. Test drive the vehicle under normal operating conditions to induce the DEF system.
    7. With the scan tool check for active DTCs.

      Is the DTC active?

      Yes 

      • Go To  3

      No 

      • Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT DTC .
  3. CHECK THE DEF SUPPLY SYSTEM FOR LEAKS 
    1. During the actuation of the Diesel Exhaust Fluid Injector Quantity Test, visually inspect the DEF Supply Pump Assembly and DEF Lines for signs of a fluid leak.

      Are there any leaks in the DEF System?

      Yes 

      • Perform the appropriate repair. Reset the SCR Timer: Using the scan tool, go to Misc. Functions>SCR Extend Mileage W Active Fault (and reset the Timer). Also, test drive the vehicle for 30 miles before beginning the PCM VERIFICATION Test.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE DEF SUPPLY LINE FOR OBSTRUCTIONS 
    1. Stop actuation of the Diesel Exhaust Fluid Injector Quantity Test.
    2. Turn the ignition off.
    3. Remove the DEF Supply Line.
    4. Check the DEF Supply Line for a restriction and check for crystallization on the DEF Supply Pump Assembly inlet fitting.

      Is the DEF Supply Line and DEF Supply Pump Assembly fitting free of obstructions?

      Yes 

      • Replace the DEF Supply Pump Assembly in accordance with the service information. Reset the SCR Timer: Using the scan tool, go to Misc. Functions>SCR Extend Mileage W Active Fault (and reset the Timer). Also, test drive the vehicle for 30 miles before beginning the PCM VERIFICATION Test.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .

      No 

      • Clear the restriction from the DEF Supply Line or DEF Supply Pump Assembly inlet fitting. Reset the SCR Timer: Using the scan tool, go to Misc. Functions>SCR Extend Mileage W Active Fault (and reset the Timer). Also, test drive the vehicle for 30 miles before beginning the PCM VERIFICATION Test.
      • Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
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