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Home › Chevrolet › 2006 › Impala LTZ › Repair and Diagnosis › Engine Performance › System › Engine Control System - 3.9L - DTC P0010 To DTC P0420 › DTC P0112 or P0113 › Circuit/System Testing

Circuit/System Testing

Always perform the.

P0112

  1. Turn ON the ignition, with the engine OFF.
  2. Disconnect the mass air flow (MAF)/IAT sensor. Observe the intake air temperature (IAT) sensor with a scan tool for -36°C (-33°F).
    • If more than -36°C (-33°F), test the signal circuit of the IAT sensor for a short to ground or a short to the IAT low reference circuit and repair as necessary. If all circuits test OK then replace the control module.
    • If less than -36°C (-33°F), replace the MAF/IAT sensor.
    • If IAT signal circuit tests OK, then replace the control module.
IMPORTANT: The sensor may be damaged if the circuit is shorted to a voltage source.

DTC P0113

  1. Turn ON the ignition, with the engine OFF.
  2. Disconnect the IAT sensor.
  3. Measure for the proper range of 4.9-5.2 volts between the IAT sensor signal circuit and a good ground with a DMM.
    • If the voltage is less than 4.9 volts, test the IAT sensor signal circuit for a high resistance or an open circuit.
    • If the voltage is more than 5.2 volts, test the IAT sensor signal circuit for a short to voltage, or any 5-volt reference.
    • If the IAT sensor signal circuit tests normal, and the voltage is still not within the proper range, then replace the control module.
  4. Turn OFF the ignition, and all electrical accessories. Allow sufficient time for all of the control modules to power down before taking a resistance measurement.
  5. Measure for less than 5 ohms of resistance between the IAT low reference circuit and a good ground.
    • If the resistance is more than 5 ohms, test the low reference circuit for a high resistance, an open circuit, or a faulty control module.
    • If all circuits test OK, then replace the IAT sensor.
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