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Home >> Chrysler >> 2011 >> 300 C, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 972 (6.7L Diesel - DTCS P063D To P205D - 2500 Hd & 3500 Hd) >> Diagnosis And Testing >> P0687-ECM Main Control Circuit High >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. ACTIVE DTC 
    1. Turn the ignition on, engine not running.
    2. With the scan tool, record all Freeze frame data.
    3. With the scan tool, erase DTCs.
    4. Turn the ignition off for 75 seconds.
    5. Start the engine. Allow the engine to run until it reaches normal operating temperature.
    6. Turn the ignition off.
    7. Turn the ignition on, engine not running.
    8. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. SCR RELAY #2 
    1. Turn the ignition off.
    2. Use a known good relay in place of the SCR Relay #2.
    3. Turn the ignition on, engine not running.
    4. With the scan tool, erase DTCs.
    5. Start and run the engine until it reaches operating temperature.
    6. Using the scan tool, read DTCs.

      Did DTC P0687 reset?

      Yes 

      • Go To  3

      No 

  3. CHECK THE (K401) SCR RELAY #2 CONTROL CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the PCM C2 harness connector.
    3. Disconnect the SCR Relay #2.
    4. Turn the ignition on, engine not running.
    5. Measure for voltage on the (K401) SCR Relay #2 Control circuit at pin 82 of the PCM C2 harness connector.

      Is there voltage present?

      Yes 

      No 

      • Go To  4
  4. POWERTRAIN CONTROL MODULE 
    1. Turn the ignition off.
    2. Reconnect the SCR Relay #2.
    3. Turn the ignition on, engine not running.
    4. Measure for voltage on the (K401) SCR Relay #2 Control circuit at pin 82 of the PCM C2 harness connector.

      Is there voltage present?

      Yes 

      No