P0403

Schematic:

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) monitors the Exhaust Gas Recirculation (EGR) valve pintle position input to ensure that the valve responds properly to commands from the PCM. The linear EGR valve is controlled by using an ignition positive driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the control circuit. If an electrical malfunction occurs, the driver signals the PCM to set DTC P0403.

CONDITIONS FOR RUNNING THE DTC
System voltage is between 9 and 16 volts.

CONDITIONS FOR SETTING THE DTC
^ The PCM detects an electrical malfunction in the control circuit for the EGR valve.
^ The above condition is present for more than 20 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
^ A faulty connection at the PCM or the EGR valve-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. Use a corresponding mating terminal to test for proper terminal tension.
^ Inspect the wiring harness for damage. If the harness appears to be OK, connect a Digital Multimeter (DMM) and check the circuit continuity while moving the connectors and the wiring harnesses related to the EGR valve. A change in the display indicates the location of the malfunction.


TEST DESCRIPTION

Diagnostic Chart:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible click when the solenoid operates. Command the EGR between 0 percent to 10 percent. Repeat the commands as necessary.
3. Verifies that the PCM is providing voltage to the solenoid.
4. Tests for an open in the ground circuit to the solenoid.
5. Determines if voltage is constantly being applied to the solenoid.
12. The PCM utilizes electrically Erasable Programmable Read-only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.