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Test E - Manifold Absolute Pressure (Map) Sensor

  1. Code 22 (from Engine Running Self-Test only). Turn ignition off and wait 10 seconds. Turn all accessories off. Check vacuum line to MAP sensor for leaks, restrictions and kinks. Check engine vacuum system for leaks. Repair as required and repeat Quick Test. If no faults or leaks, go to next step.
  2. Turn ignition off and wait 10 seconds. Disconnect vacuum line from MAP sensor and install vacuum pump to sensor. Apply 20 in. Hg vacuum to sensor. If sensor holds vacuum, remove pump, reconnect sensor and go to next step. If sensor does not hold vacuum, replace MAP sensor and repeat Quick Test.
  3. If code 41 was recorded in Engine Running Self-Test, go to TEST K - FUEL CONTROL  . If code 41 not present, go to next step.
  4. Turn ignition off and wait 10 seconds. Disconnect electrical harness from MAP sensor and inspect. Service as required. With DVOM on 20 volt scale, turn ignition on. Measure voltage from voltage reference circuit to signal return circuit of MAP sensor harness connector. If between 4-6 volts, go to next step. If less than 4 volts, go to step 6). If greater than 6 volts, go to TEST C - REFERENCE VOLTAGE  .
  5. Ignition on and MAP sensor harness disconnected. With DVOM on 20 volt scale, measure voltage from MAP signal circuit to signal return circuit of MAP sensor harness connector. If less than 4 volts, go to next step. If 4 volts or more, go to step 8).
  6. Turn ignition off and wait 10 seconds. Harness disconnected at MAP sensor. Disconnect 60-pin connector at ECA and inspect. Install breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance from voltage reference circuit of MAP sensor harness connector to box pin 26; from MAP signal circuit of MAP sensor harness connector to box pin 45 and from signal return circuit of MAP sensor harness connector to box pin 46. If all less than 5 ohms, go to next step. If any 5 ohms or more, repair open circuit. Remove breakout box, reconnect ECA and MAP sensor and repeat Quick Test.
  7. Ignition off, breakout box installed, ECA and MAP sensor disconnected. With DVOM on 200 ohm scale, measure resistance from box pin 26 to box pins 40, 46 and 60 in turn. Then measure resistance from box pin 45 to box pins 40, 46 and 60 in turn. If any is less than 100 ohms, repair short circuit. Remove breakout box, reconnect ECA and MAP sensor and repeat Quick Test. If all readings are 100 ohms or more, go to step 9).
  8. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Install breakout box and leave ECA disconnected. Harness disconnected at MAP sensor. With DVOM on 200,000 ohm scale, measure resistance from box pin 45 to box pins 26, 37 and 57 in turn. If any reading less than 10,000 ohms, repair short circuit. Remove breakout box, reconnect ECA and MAP sensor and repeat Quick Test. If all readings 10,000 ohms or more, go to next step.
  9. With ignition off, remove breakout box and reconnect ECA. Connect MAP sensor harness connector and vacuum line to a substitute MAP sensor. Perform Engine Running Self-Test. If code 22 present, replace ECA. Connect vacuum line and harness to original MAP sensor and repeat Quick Test. If no code 22, install substitute MAP sensor and repeat Quick Test.
  10. Code 72. Turn ignition off and wait 10 seconds. Remove vacuum supply line at MAP sensor and tee in vacuum gauge. Perform Engine Running Self-Test while observing vacuum gauge. If vacuum decrease is 9 in. Hg or more and code 72 not present, disconnect vacuum gauge and service other codes as required. If vacuum decrease is 9 in. Hg or more and code 72 present, replace MAP sensor and repeat Quick Test. If vacuum decrease is less than 9 in. Hg, go to next step.
  11. Check vacuum lines for proper routing. Check MAP sensor for kinks or blockage. If vacuum lines are okay, EEC system operating properly; check engine for cause of vacuum loss. If vacuum lines are not okay, repair as required and repeat step 10).
  12. Continuous Monitor Code 22. Disconnect vacuum line at MAP sensor and install vacuum pump. Slowly apply 25 in. Hg vacuum to sensor, then slowly bleed off vacuum. Enter Continuous Monitor mode and observe volt/ohmmeter for fault indication while doing the following: Lightly tap on MAP sensor to simulate road shock. Wiggle sensor connector. If fault is indicated, disconnect harness connectors at MAP and ECA. If connectors and terminals are okay, replace sensor and repeat Quick Test. If no fault indicated, go to next step.
  13. Observe volt/ohmmeter while performing the following: Beginning at MAP, wiggle, shake or bend small sections of harness while working way to dash panel. Then repeating process from panel to ECA. If fault is indicated, isolate and repair problem and repeat Quick Test. If no fault indicated, go to next step.
  14. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect connector and terminals for damage. If damaged, service as required and repeat Quick Test. If okay, fault cannot be duplicated at this time. Continuous Code 22 testing is complete.
Fig 1: Manifold Absolute Pressure (MAP) Sensor Circuit
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