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Home >> Chevrolet >> 2009 >> HHR SS, Standard >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (Engine Controls And Fuel - 2.2L Or 2.4L - DTC P0351 To DTC P2544) >> DTC P2120, P2122, P2123, P2125, P2127, P2128, or P2138 (2.4L) >> Circuit/System Testing (2.4L)

Circuit/System Testing (2.4L)

WARNING: This page is about a different variant/trim than selected.
  1. Ignition ON, disconnect the accelerator pedal harness connector at the accelerator pedal. Allow sufficient time for the ECM to power down.
  2. Test for less than 3 ohms between each low reference circuit terminals 5 and 4 and ground.
    • If greater than 3 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 volts between each 5-volt reference circuit terminals 1 and 2 and ground.
    • If less than 4.8 volts, test affected 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
    • If greater than 5.2 volts, test the affected 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Ignition ON, verify the scan tool APP sensor 1 and 2 voltages are less than 0.1 volt.
    • If greater than 0.1 volt, test the APP sensor 1 and 2 signal circuits terminal 6 and 3 for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2 of the APP sensor 1, and verify the APP sensor 1 voltage is greater than 4.8 volts.
    • If less than 4.8 volts, test the APP sensor 1 signal circuit for an open, or short to ground. If the circuit tests normal, replace the control module.
  6. Install a 3A fused jumper wire between the signal circuit terminal 6 and the 5-volt reference circuit terminal 1 of the APP sensor 2, and verify that the APP sensor 2 voltage is greater than 4.8 volts.
    • If less than 4.8 volts, test the APP sensor 2 signal circuit for an open/high resistance, or short to ground. If the circuit tests normal, replace the ECM.
  7. Ignition OFF, disconnect the harness connector at the ECM.
  8. Test for less than 5 ohms on all APP sensor circuits between the following terminals:
    • The signal circuit terminal 6 to the corresponding ECM terminal
    • The signal circuit terminal 3 to the corresponding ECM terminal
    • The 5-volt reference circuit terminal 1 to the corresponding ECM terminal
    • The 5-volt reference circuit terminal 2 to the corresponding ECM terminal
    • If greater than 5 ohms, repair the affected circuit.
  9. Test for infinite resistance between APP sensor 1 signal circuit terminal 3 and APP sensor 2 signal circuit terminal 6.
    • If less than infinite resistance, repair the short between APP sensor 1 signal circuit and APP sensor 2 signal circuit.
    • If all circuits test normal, replace the accelerator pedal.
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