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Home >> GMC >> 1998 >> Forward Control 7.4 B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 7.4L >> Diagnostic Trouble Codes >> DTC P0106 - Map Sensor System Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
  2. Install scan tool. Turn ignition on, with engine off. Monitor MAP sensor voltage on scan tool. If sensor voltage is 0.4 volt, go to next step. If sensor voltage is not 0.4 volt, go to step 6).
  3. Disconnect and plug MAP sensor vacuum source. Connect a hand-held vacuum pump to MAP sensor. Start engine. Observe MAP sensor voltage on scan tool. Using vacuum pump, apply 10 in. Hg to MAP sensor. Observe MAP sensor voltage. Subtract this reading from voltage reading noted in step 2). If difference is greater than 1.5 volts, see DIAGNOSTIC AIDS. If difference is not greater than 1.5 volts, go to next step.
  4. Check MAP sensor connections. If problem is found, go to next step. If connections are okay, go to step 7).
  5. Repair connections as necessary. After repairs, go to step 7).
  6. Replace MAP sensor. After replacing sensor, go to next step.
  7. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. 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).
  8. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.
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