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DTC P0400: Exhaust Gas RECIRCULATION (EGR) Flow Malfunction (Esteem 1.8L)

  1. If scan tool is not available, go to step  3 . If scan tool is available, turn ignition off. Install scan tool. Start engine and allow it to reach normal operating temperature. With engine at idle, open EGR valve using MISC TEST mode. As EGR valve opens and engine idle speed decreases, go to next step. If EGR valve opens and engine idle speed does not decrease, go to step  3 .
  2. Turn ignition on. Measure (backprobe) voltage between PCM connector E91 terminal No. 7 (Green wire) and connector C20 terminal No. 27 (Orange wire). Voltage should be 3.9-5.0 volts. Start and idle engine. Voltage should be 1.4-2.4 volts. If voltages are to specification, replace PCM. If voltages are not to specification, check Manifold Differential Pressure (MDP) sensor. See DTC P1408: MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR CIRCUIT MALFUNCTION (ESTEEM 1.8L)  .
  3. Ensure ignition is off. Disconnect EGR valve connector. Turn ignition on. Measure voltage between ground and EGR valve connector terminal No. 2 (Red/Black wire) and terminal No. 5 (Red/Black wire). If 10-14 volts are present in both cases, go to next step. If 10-14 volts are not present in both cases, repair open or short circuit in Red/Black wire.
  4. Ensure ignition is off. Reconnect EGR valve connector. Disconnect ECM connectors. Measure resistance between ECM connector E92, terminal No. 8 (Red/Black wire), and ECM connector C20, terminals No. 3 (Light Green wire), No. 13 (Light Green/White wire), No. 14 (Light Green/Red wire) and No. 15 (Light Green/Yellow wire). If each resistance measurement is 20-24 ohms at 68°F (20°C), go to next step. If each resistance measurement is not 20-24 ohms at 68°F (20°C), check for faulty Light Green, Light Green/White, Light Green/Red or Light Green/Yellow wire.
  5. Turn ignition on. Measure (backprobe) voltage between PCM connector E91 terminal No. 7 (Green wire) and connector C20 terminal No. 27 (Orange wire). Voltage should be 3.9-5.0 volts. Start and idle engine. Voltage should be 1.4-2.4 volts. If voltages are to specification, replace PCM. If voltages are not to specification, check Manifold Differential Pressure (MDP) sensor. See DTC P1408: MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR CIRCUIT MALFUNCTION (ESTEEM 1.8L)  .
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