Refer to Engine Controls Schematic
MAF, EGR, EVAP Purge and EVAP Canister Valve
.
Circuit Description
The PCM monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM and to detect a fault if the pintle position sensor circuit is open or shorted. If the PCM detects an excessively low EGR Feedback signal voltage, DTC P0405 will set.
Conditions for Running the DTC
System voltage is greater than 11.0 volts.
Conditions for Setting the DTC
| • | EGR Feedback is less than 0.3 volt at any time. |
| • | The condition is present for longer 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/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has 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
Inspect for the following:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
Numbers below refer to the step numbers on the Diagnostic Table:
-
Verifies that the malfunction is present.
-
If DTC P0405 will only set under certain conditions, the malfunction may be intermittent; refer to Diagnostic Aids. If an intermittent wiring problem is not present, check for a poor connection at the PCM or the EGR valve.
-
This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||||||||
Does Desired EGR Position remain close to Actual EGR Position at all commanded positions? | -- | |||||||||
Does the scan tool indicate DTC P0405 failed this ignition? | -- | Go to Diagnostic Aids | ||||||||
4 |
Is the voltage at the specified value? | 5.0V | ||||||||
5 | Probe the EGR valve pintle position circuit at the EGR valve harness connector with a test lamp connected to battery positive voltage. Is the test lamp on? | -- | ||||||||
6 |
Is the Actual EGR Position at the specified value? | 100% | ||||||||
7 |
Did you find and correct the condition? | -- | ||||||||
8 |
Is the test lamp on? | -- | ||||||||
9 | Probe the 5 Volt Reference A circuit with a test lamp to battery positive voltage. Is the test lamp on? | -- | ||||||||
10 |
Is the test lamp on? | -- | ||||||||
11 | Test for an open in the 5 Volt Reference A circuit between the PCM and the EGR valve. Refer to Wiring Repairs in Wiring Systems. Did you find and complete the repair? | -- | ||||||||
12 | Locate and correct the short to ground in the EGR valve pintle position circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||
13 | Inspect for the following conditions:
Did you find and correct the condition? | -- | ||||||||
14 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Notice: If the EGR valve shows signs of excessive heat, inspect the exhaust
system for blockage--possibly a plugged converter--using the procedure
found on the Restricted Exhaust System Check. If the exhaust system is restricted,
repair the cause. Inspect for an open injector caused by one or more of the
following conditions:
Did you complete the repair? | -- | -- | |||||||
15 | Test the EGR valve pintle position circuit for a short to the sensor ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
16 | Locate and repair short to ground in the 5 Volt Reference A circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||
17 | Test the circuits related to the EGR valve for a poor terminal connection at the PCM. Refer to Testing for Continuity , and Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | ||||||||
|
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the repair? | -- | -- | ||||||||
19 |
Does the scan tool indicate DTC P0405 failed this ignition? | -- | System OK |
