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Home >> Jeep >> 2003 >> Grand Cherokee Laredo, 4.7 N, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1297: No Change In Map From Start To Run >> Testing
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DTC P1297: No Change In Map From Start To Run: Testing

    NOTE: If a MAP High or Low DTC set along with DTC P1297, diagnose the High or Low DTC first before continuing with this test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  1. Turn ignition on, engine not running. With the DRBIII®, read DTCs. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to INTERMITTENT CONDITION  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn the ignition off. Remove the MAP Sensor. Inspect the vacuum port, check for restrictions or any foreign materials. Were any restrictions found? If yes, repair as necessary. If no, go to the next step.
    NOTE: Reinstall the MAP Sensor before continuing.
  3. Turn ignition on, engine not running. With the DRBIII®, read the MAP Sensor voltage. Is the voltage below 3.19 volts? If yes, go to the next step. If no, refer to the INTERMITTENT CONDITION  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn the ignition off. Disconnect the MAP Sensor harness connector. Turn ignition on, engine not running. Measure the voltage on the (K7) 5-Volt Supply circuit at the MAP Sensor harness connector. Is the voltage between 4.5 to 5.2 volts? If yes, go to the next step. If no, go to step  8
  5. With the DRBIII®, monitor the MAP Sensor voltage with the Sensor harness connector disconnected. Is the voltage above 1.2 volts? If yes, replace the MAP Sensor. If no, go to the next step.
  6. Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance between ground and the (K1) MAP Sensor Signal circuit at the MAP Sensor harness connector. Is the resistance below 100 ohms? If yes, repair the short to ground in the (K1) MAP Sensor Signal circuit. If no, go to the next step.
  7. Measure the resistance between the (K1) MAP Sensor Signal circuit and the (K4) Sensor ground circuit at the MAP Sensor harness connector. Is the resistance below 100 ohms? If yes, repair the short between the (K4) Sensor ground and the (K1) MAP Sensor Signal circuit. If no, go to step  10.
  8. Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance of the (K7) 5-Volt Supply circuit from the MAP Sensor harness connector to the PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to the next step. If no, repair the open in the (K7) 5-Volt Supply circuit.
  9. Measure the resistance between ground and the (K7) 5-Volt Supply circuit in the MAP Sensor harness connector. Is the resistance below 100 ohms? If yes, repair the short to ground in the (K7) 5-Volt Supply circuit. If no, go to the next step.
    10. NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
  10. Using the wiring diagram as a guide, inspect the wire harness and connectors. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
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