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Home >> GMC >> 1997 >> C3500 HD 6.5 F, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 6.5L >> Diagnostic Trouble Codes >> DTC P0604 - Control Module Random Access Memory >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform Powertrain ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the BASIC TESTING - 6.5L DIESEL article. Then go to next step.
  2. Check all PCM connections. Repair as necessary. After repairs, go to step 4). If connections are okay, go to next step.
  3. Replace PCM. After replacing PCM, go to next step.
  4. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0604. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2).
  5. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
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